1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | IO::AIO - Asynchronous Input/Output |
3 | IO::AIO - Asynchronous/Advanced Input/Output |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use IO::AIO; |
7 | use IO::AIO; |
8 | |
8 | |
9 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
9 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
10 | my ($fh) = @_; |
10 | my $fh = shift |
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11 | or die "/etc/passwd: $!"; |
11 | ... |
12 | ... |
12 | }; |
13 | }; |
13 | |
14 | |
14 | aio_unlink "/tmp/file", sub { }; |
15 | aio_unlink "/tmp/file", sub { }; |
15 | |
16 | |
16 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
17 | aio_read $fh, 30000, 1024, $buffer, 0, sub { |
17 | $_[0] > 0 or die "read error: $!"; |
18 | $_[0] > 0 or die "read error: $!"; |
18 | }; |
19 | }; |
19 | |
20 | |
20 | # Event |
21 | # version 2+ has request and group objects |
21 | Event->io (fd => IO::AIO::poll_fileno, |
22 | use IO::AIO 2; |
22 | poll => 'r', |
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23 | cb => \&IO::AIO::poll_cb); |
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24 | |
23 | |
25 | # Glib/Gtk2 |
24 | aioreq_pri 4; # give next request a very high priority |
26 | add_watch Glib::IO IO::AIO::poll_fileno, |
25 | my $req = aio_unlink "/tmp/file", sub { }; |
27 | \&IO::AIO::poll_cb; |
26 | $req->cancel; # cancel request if still in queue |
28 | |
27 | |
29 | # Tk |
28 | my $grp = aio_group sub { print "all stats done\n" }; |
30 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
29 | add $grp aio_stat "..." for ...; |
31 | readable => \&IO::AIO::poll_cb); |
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32 | |
30 | |
33 | =head1 DESCRIPTION |
31 | =head1 DESCRIPTION |
34 | |
32 | |
35 | This module implements asynchronous I/O using whatever means your |
33 | This module implements asynchronous I/O using whatever means your |
36 | operating system supports. |
34 | operating system supports. It is implemented as an interface to C<libeio> |
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35 | (L<http://software.schmorp.de/pkg/libeio.html>). |
37 | |
36 | |
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37 | Asynchronous means that operations that can normally block your program |
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38 | (e.g. reading from disk) will be done asynchronously: the operation |
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39 | will still block, but you can do something else in the meantime. This |
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40 | is extremely useful for programs that need to stay interactive even |
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41 | when doing heavy I/O (GUI programs, high performance network servers |
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42 | etc.), but can also be used to easily do operations in parallel that are |
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43 | normally done sequentially, e.g. stat'ing many files, which is much faster |
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44 | on a RAID volume or over NFS when you do a number of stat operations |
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45 | concurrently. |
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46 | |
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47 | While most of this works on all types of file descriptors (for |
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48 | example sockets), using these functions on file descriptors that |
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49 | support nonblocking operation (again, sockets, pipes etc.) is |
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50 | very inefficient. Use an event loop for that (such as the L<EV> |
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51 | module): IO::AIO will naturally fit into such an event loop itself. |
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52 | |
38 | Currently, a number of threads are started that execute your read/writes |
53 | In this version, a number of threads are started that execute your |
39 | and signal their completion. You don't need thread support in your libc or |
54 | requests and signal their completion. You don't need thread support |
40 | perl, and the threads created by this module will not be visible to the |
55 | in perl, and the threads created by this module will not be visible |
41 | pthreads library. In the future, this module might make use of the native |
56 | to perl. In the future, this module might make use of the native aio |
42 | aio functions available on many operating systems. However, they are often |
57 | functions available on many operating systems. However, they are often |
43 | not well-supported (Linux doesn't allow them on normal files currently, |
58 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
44 | for example), and they would only support aio_read and aio_write, so the |
59 | files currently, for example), and they would only support aio_read and |
45 | remaining functionality would have to be implemented using threads anyway. |
60 | aio_write, so the remaining functionality would have to be implemented |
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61 | using threads anyway. |
46 | |
62 | |
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63 | In addition to asynchronous I/O, this module also exports some rather |
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64 | arcane interfaces, such as C<madvise> or linux's C<splice> system call, |
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65 | which is why the C<A> in C<AIO> can also mean I<advanced>. |
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66 | |
47 | Although the module will work with in the presence of other threads, it is |
67 | Although the module will work in the presence of other (Perl-) threads, |
48 | currently not reentrant, so use appropriate locking yourself. |
68 | it is currently not reentrant in any way, so use appropriate locking |
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69 | yourself, always call C<poll_cb> from within the same thread, or never |
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70 | call C<poll_cb> (or other C<aio_> functions) recursively. |
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71 | |
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72 | =head2 EXAMPLE |
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73 | |
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74 | This is a simple example that uses the EV module and loads |
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75 | F</etc/passwd> asynchronously: |
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76 | |
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77 | use EV; |
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78 | use IO::AIO; |
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79 | |
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80 | # register the IO::AIO callback with EV |
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81 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
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82 | |
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83 | # queue the request to open /etc/passwd |
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84 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
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85 | my $fh = shift |
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86 | or die "error while opening: $!"; |
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87 | |
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88 | # stat'ing filehandles is generally non-blocking |
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89 | my $size = -s $fh; |
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90 | |
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91 | # queue a request to read the file |
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92 | my $contents; |
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93 | aio_read $fh, 0, $size, $contents, 0, sub { |
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94 | $_[0] == $size |
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95 | or die "short read: $!"; |
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96 | |
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97 | close $fh; |
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98 | |
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99 | # file contents now in $contents |
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100 | print $contents; |
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101 | |
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102 | # exit event loop and program |
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103 | EV::break; |
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104 | }; |
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105 | }; |
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106 | |
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107 | # possibly queue up other requests, or open GUI windows, |
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108 | # check for sockets etc. etc. |
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109 | |
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110 | # process events as long as there are some: |
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111 | EV::run; |
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112 | |
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113 | =head1 REQUEST ANATOMY AND LIFETIME |
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114 | |
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115 | Every C<aio_*> function creates a request. which is a C data structure not |
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116 | directly visible to Perl. |
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117 | |
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118 | If called in non-void context, every request function returns a Perl |
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119 | object representing the request. In void context, nothing is returned, |
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120 | which saves a bit of memory. |
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121 | |
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122 | The perl object is a fairly standard ref-to-hash object. The hash contents |
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123 | are not used by IO::AIO so you are free to store anything you like in it. |
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124 | |
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125 | During their existance, aio requests travel through the following states, |
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126 | in order: |
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127 | |
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128 | =over 4 |
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129 | |
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130 | =item ready |
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131 | |
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132 | Immediately after a request is created it is put into the ready state, |
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133 | waiting for a thread to execute it. |
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134 | |
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135 | =item execute |
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136 | |
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137 | A thread has accepted the request for processing and is currently |
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138 | executing it (e.g. blocking in read). |
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139 | |
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140 | =item pending |
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141 | |
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142 | The request has been executed and is waiting for result processing. |
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143 | |
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144 | While request submission and execution is fully asynchronous, result |
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145 | processing is not and relies on the perl interpreter calling C<poll_cb> |
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146 | (or another function with the same effect). |
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147 | |
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148 | =item result |
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149 | |
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150 | The request results are processed synchronously by C<poll_cb>. |
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151 | |
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152 | The C<poll_cb> function will process all outstanding aio requests by |
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153 | calling their callbacks, freeing memory associated with them and managing |
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154 | any groups they are contained in. |
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155 | |
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156 | =item done |
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157 | |
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158 | Request has reached the end of its lifetime and holds no resources anymore |
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159 | (except possibly for the Perl object, but its connection to the actual |
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160 | aio request is severed and calling its methods will either do nothing or |
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161 | result in a runtime error). |
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162 | |
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163 | =back |
49 | |
164 | |
50 | =cut |
165 | =cut |
51 | |
166 | |
52 | package IO::AIO; |
167 | package IO::AIO; |
53 | |
168 | |
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169 | use Carp (); |
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170 | |
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171 | use common::sense; |
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172 | |
54 | use base 'Exporter'; |
173 | use base 'Exporter'; |
55 | |
174 | |
56 | use Fcntl (); |
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57 | |
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58 | BEGIN { |
175 | BEGIN { |
59 | $VERSION = 0.2; |
176 | our $VERSION = 4.51; |
60 | |
177 | |
61 | @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink |
178 | our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close |
62 | aio_fsync aio_fdatasync aio_readahead); |
179 | aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx |
63 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
180 | aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl |
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181 | aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range |
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182 | aio_pathsync aio_readahead aio_fiemap aio_allocate |
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183 | aio_rename aio_rename2 aio_link aio_move aio_copy aio_group |
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184 | aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown |
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185 | aio_chmod aio_utime aio_truncate |
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186 | aio_msync aio_mtouch aio_mlock aio_mlockall |
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187 | aio_statvfs |
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188 | aio_slurp |
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189 | aio_wd); |
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190 | |
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191 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
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192 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
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193 | min_parallel max_parallel max_idle idle_timeout |
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194 | nreqs nready npending nthreads |
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195 | max_poll_time max_poll_reqs |
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196 | sendfile fadvise madvise |
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197 | mmap munmap mremap munlock munlockall); |
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198 | |
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199 | push @AIO_REQ, qw(aio_busy); # not exported |
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200 | |
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201 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
64 | |
202 | |
65 | require XSLoader; |
203 | require XSLoader; |
66 | XSLoader::load IO::AIO, $VERSION; |
204 | XSLoader::load ("IO::AIO", $VERSION); |
67 | } |
205 | } |
68 | |
206 | |
69 | =head1 FUNCTIONS |
207 | =head1 FUNCTIONS |
70 | |
208 | |
71 | =head2 AIO FUNCTIONS |
209 | =head2 QUICK OVERVIEW |
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210 | |
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211 | This section simply lists the prototypes most of the functions for |
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212 | quick reference. See the following sections for function-by-function |
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213 | documentation. |
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214 | |
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215 | aio_wd $pathname, $callback->($wd) |
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216 | aio_open $pathname, $flags, $mode, $callback->($fh) |
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217 | aio_close $fh, $callback->($status) |
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218 | aio_seek $fh,$offset,$whence, $callback->($offs) |
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219 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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220 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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221 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
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222 | aio_readahead $fh,$offset,$length, $callback->($retval) |
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223 | aio_stat $fh_or_path, $callback->($status) |
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224 | aio_lstat $fh, $callback->($status) |
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225 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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226 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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227 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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228 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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229 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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230 | aio_allocate $fh, $mode, $offset, $len, $callback->($status) |
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231 | aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
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232 | aio_unlink $pathname, $callback->($status) |
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233 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
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234 | aio_link $srcpath, $dstpath, $callback->($status) |
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235 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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236 | aio_readlink $pathname, $callback->($link) |
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237 | aio_realpath $pathname, $callback->($path) |
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238 | aio_rename $srcpath, $dstpath, $callback->($status) |
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239 | aio_rename2 $srcpath, $dstpath, $flags, $callback->($status) |
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240 | aio_mkdir $pathname, $mode, $callback->($status) |
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241 | aio_rmdir $pathname, $callback->($status) |
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242 | aio_readdir $pathname, $callback->($entries) |
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243 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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244 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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245 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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246 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
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247 | aio_load $pathname, $data, $callback->($status) |
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248 | aio_copy $srcpath, $dstpath, $callback->($status) |
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249 | aio_move $srcpath, $dstpath, $callback->($status) |
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250 | aio_rmtree $pathname, $callback->($status) |
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251 | aio_fcntl $fh, $cmd, $arg, $callback->($status) |
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252 | aio_ioctl $fh, $request, $buf, $callback->($status) |
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253 | aio_sync $callback->($status) |
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254 | aio_syncfs $fh, $callback->($status) |
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255 | aio_fsync $fh, $callback->($status) |
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256 | aio_fdatasync $fh, $callback->($status) |
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257 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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258 | aio_pathsync $pathname, $callback->($status) |
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259 | aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status) |
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260 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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261 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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262 | aio_mlockall $flags, $callback->($status) |
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263 | aio_group $callback->(...) |
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264 | aio_nop $callback->() |
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265 | |
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266 | $prev_pri = aioreq_pri [$pri] |
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267 | aioreq_nice $pri_adjust |
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268 | |
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269 | IO::AIO::poll_wait |
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270 | IO::AIO::poll_cb |
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271 | IO::AIO::poll |
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272 | IO::AIO::flush |
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273 | IO::AIO::max_poll_reqs $nreqs |
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274 | IO::AIO::max_poll_time $seconds |
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275 | IO::AIO::min_parallel $nthreads |
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276 | IO::AIO::max_parallel $nthreads |
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277 | IO::AIO::max_idle $nthreads |
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278 | IO::AIO::idle_timeout $seconds |
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279 | IO::AIO::max_outstanding $maxreqs |
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280 | IO::AIO::nreqs |
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281 | IO::AIO::nready |
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282 | IO::AIO::npending |
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283 | $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL] |
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284 | IO::AIO::min_fdlimit $nfd [EXPERIMENTAL] |
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285 | |
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286 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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287 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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288 | IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] |
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289 | IO::AIO::munmap $scalar |
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290 | IO::AIO::mremap $scalar, $new_length, $flags[, $new_address] |
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291 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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292 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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293 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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294 | IO::AIO::munlockall |
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295 | |
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296 | =head2 API NOTES |
72 | |
297 | |
73 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
298 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
74 | with the same name (sans C<aio_>). The arguments are similar or identical, |
299 | with the same name (sans C<aio_>). The arguments are similar or identical, |
75 | and they all accept an additional C<$callback> argument which must be |
300 | and they all accept an additional (and optional) C<$callback> argument |
76 | a code reference. This code reference will get called with the syscall |
301 | which must be a code reference. This code reference will be called after |
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302 | the syscall has been executed in an asynchronous fashion. The results |
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303 | of the request will be passed as arguments to the callback (and, if an |
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304 | error occured, in C<$!>) - for most requests the syscall return code (e.g. |
77 | return code (e.g. most syscalls return C<-1> on error, unlike perl, which |
305 | most syscalls return C<-1> on error, unlike perl, which usually delivers |
78 | usually delivers "false") as it's sole argument when the given syscall has |
306 | "false"). |
79 | been executed asynchronously. |
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80 | |
307 | |
81 | All functions that expect a filehandle will also accept a file descriptor. |
308 | Some requests (such as C<aio_readdir>) pass the actual results and |
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309 | communicate failures by passing C<undef>. |
82 | |
310 | |
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311 | All functions expecting a filehandle keep a copy of the filehandle |
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312 | internally until the request has finished. |
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313 | |
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314 | All functions return request objects of type L<IO::AIO::REQ> that allow |
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315 | further manipulation of those requests while they are in-flight. |
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316 | |
83 | The filenames you pass to these routines I<must> be absolute. The reason |
317 | The pathnames you pass to these routines I<should> be absolute. The |
84 | is that at the time the request is being executed, the current working |
318 | reason for this is that at the time the request is being executed, the |
85 | directory could have changed. Alternatively, you can make sure that you |
319 | current working directory could have changed. Alternatively, you can |
86 | never change the current working directory. |
320 | make sure that you never change the current working directory anywhere |
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321 | in the program and then use relative paths. You can also take advantage |
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322 | of IO::AIOs working directory abstraction, that lets you specify paths |
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323 | relative to some previously-opened "working directory object" - see the |
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324 | description of the C<IO::AIO::WD> class later in this document. |
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325 | |
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326 | To encode pathnames as octets, either make sure you either: a) always pass |
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327 | in filenames you got from outside (command line, readdir etc.) without |
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328 | tinkering, b) are in your native filesystem encoding, c) use the Encode |
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329 | module and encode your pathnames to the locale (or other) encoding in |
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330 | effect in the user environment, d) use Glib::filename_from_unicode on |
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331 | unicode filenames or e) use something else to ensure your scalar has the |
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332 | correct contents. |
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333 | |
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334 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
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335 | handles correctly whether it is set or not. |
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336 | |
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337 | =head2 AIO REQUEST FUNCTIONS |
87 | |
338 | |
88 | =over 4 |
339 | =over 4 |
89 | |
340 | |
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341 | =item $prev_pri = aioreq_pri [$pri] |
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342 | |
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343 | Returns the priority value that would be used for the next request and, if |
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344 | C<$pri> is given, sets the priority for the next aio request. |
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345 | |
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346 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
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347 | and C<4>, respectively. Requests with higher priority will be serviced |
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348 | first. |
|
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349 | |
|
|
350 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
|
|
351 | functions. |
|
|
352 | |
|
|
353 | Example: open a file with low priority, then read something from it with |
|
|
354 | higher priority so the read request is serviced before other low priority |
|
|
355 | open requests (potentially spamming the cache): |
|
|
356 | |
|
|
357 | aioreq_pri -3; |
|
|
358 | aio_open ..., sub { |
|
|
359 | return unless $_[0]; |
|
|
360 | |
|
|
361 | aioreq_pri -2; |
|
|
362 | aio_read $_[0], ..., sub { |
|
|
363 | ... |
|
|
364 | }; |
|
|
365 | }; |
|
|
366 | |
|
|
367 | |
|
|
368 | =item aioreq_nice $pri_adjust |
|
|
369 | |
|
|
370 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
|
371 | priority, so the effect is cumulative. |
|
|
372 | |
|
|
373 | |
90 | =item aio_open $pathname, $flags, $mode, $callback |
374 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
91 | |
375 | |
92 | Asynchronously open or create a file and call the callback with a newly |
376 | Asynchronously open or create a file and call the callback with a newly |
93 | created filehandle for the file. |
377 | created filehandle for the file (or C<undef> in case of an error). |
94 | |
378 | |
95 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
379 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
96 | for an explanation. |
380 | for an explanation. |
97 | |
381 | |
98 | The C<$mode> argument is a bitmask. See the C<Fcntl> module for a |
382 | The C<$flags> argument is a bitmask. See the C<Fcntl> module for a |
99 | list. They are the same as used in C<sysopen>. |
383 | list. They are the same as used by C<sysopen>. |
|
|
384 | |
|
|
385 | Likewise, C<$mode> specifies the mode of the newly created file, if it |
|
|
386 | didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, |
|
|
387 | except that it is mandatory (i.e. use C<0> if you don't create new files, |
|
|
388 | and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified |
|
|
389 | by the umask in effect then the request is being executed, so better never |
|
|
390 | change the umask. |
100 | |
391 | |
101 | Example: |
392 | Example: |
102 | |
393 | |
103 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
394 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
104 | if ($_[0]) { |
395 | if ($_[0]) { |
105 | print "open successful, fh is $_[0]\n"; |
396 | print "open successful, fh is $_[0]\n"; |
106 | ... |
397 | ... |
107 | } else { |
398 | } else { |
108 | die "open failed: $!\n"; |
399 | die "open failed: $!\n"; |
109 | } |
400 | } |
110 | }; |
401 | }; |
111 | |
402 | |
|
|
403 | In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>, |
|
|
404 | C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the |
|
|
405 | following POSIX and non-POSIX constants are available (missing ones on |
|
|
406 | your system are, as usual, C<0>): |
|
|
407 | |
|
|
408 | C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, |
|
|
409 | C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, |
|
|
410 | C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>. |
|
|
411 | |
|
|
412 | |
112 | =item aio_close $fh, $callback |
413 | =item aio_close $fh, $callback->($status) |
113 | |
414 | |
114 | Asynchronously close a file and call the callback with the result |
415 | Asynchronously close a file and call the callback with the result |
115 | code. I<WARNING:> although accepted, you should not pass in a perl |
416 | code. |
116 | filehandle here, as perl will likely close the file descriptor itself when |
|
|
117 | the filehandle is destroyed. Normally, you can safely call perls C<close> |
|
|
118 | or just let filehandles go out of scope. |
|
|
119 | |
417 | |
|
|
418 | Unfortunately, you can't do this to perl. Perl I<insists> very strongly on |
|
|
419 | closing the file descriptor associated with the filehandle itself. |
|
|
420 | |
|
|
421 | Therefore, C<aio_close> will not close the filehandle - instead it will |
|
|
422 | use dup2 to overwrite the file descriptor with the write-end of a pipe |
|
|
423 | (the pipe fd will be created on demand and will be cached). |
|
|
424 | |
|
|
425 | Or in other words: the file descriptor will be closed, but it will not be |
|
|
426 | free for reuse until the perl filehandle is closed. |
|
|
427 | |
|
|
428 | =cut |
|
|
429 | |
|
|
430 | =item aio_seek $fh, $offset, $whence, $callback->($offs) |
|
|
431 | |
|
|
432 | Seeks the filehandle to the new C<$offset>, similarly to perl's |
|
|
433 | C<sysseek>. The C<$whence> can use the traditional values (C<0> for |
|
|
434 | C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for |
|
|
435 | C<IO::AIO::SEEK_END>). |
|
|
436 | |
|
|
437 | The resulting absolute offset will be passed to the callback, or C<-1> in |
|
|
438 | case of an error. |
|
|
439 | |
|
|
440 | In theory, the C<$whence> constants could be different than the |
|
|
441 | corresponding values from L<Fcntl>, but perl guarantees they are the same, |
|
|
442 | so don't panic. |
|
|
443 | |
|
|
444 | As a GNU/Linux (and maybe Solaris) extension, also the constants |
|
|
445 | C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they |
|
|
446 | could be found. No guarantees about suitability for use in C<aio_seek> or |
|
|
447 | Perl's C<sysseek> can be made though, although I would naively assume they |
|
|
448 | "just work". |
|
|
449 | |
120 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
450 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
121 | |
451 | |
122 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
452 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
123 | |
453 | |
124 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
454 | Reads or writes C<$length> bytes from or to the specified C<$fh> and |
125 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
455 | C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and |
126 | callback without the actual number of bytes read (or -1 on error, just |
456 | calls the callback with the actual number of bytes transferred (or -1 on |
127 | like the syscall). |
457 | error, just like the syscall). |
128 | |
458 | |
|
|
459 | C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to |
|
|
460 | offset plus the actual number of bytes read. |
|
|
461 | |
|
|
462 | If C<$offset> is undefined, then the current file descriptor offset will |
|
|
463 | be used (and updated), otherwise the file descriptor offset will not be |
|
|
464 | changed by these calls. |
|
|
465 | |
|
|
466 | If C<$length> is undefined in C<aio_write>, use the remaining length of |
|
|
467 | C<$data>. |
|
|
468 | |
|
|
469 | If C<$dataoffset> is less than zero, it will be counted from the end of |
|
|
470 | C<$data>. |
|
|
471 | |
|
|
472 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
|
|
473 | is outstanding. Modifying it can result in segfaults or World War III (if |
|
|
474 | the necessary/optional hardware is installed). |
|
|
475 | |
129 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at |
476 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
130 | offset C<0> within the scalar: |
477 | offset C<0> within the scalar: |
131 | |
478 | |
132 | aio_read $fh, 7, 15, $buffer, 0, sub { |
479 | aio_read $fh, 7, 15, $buffer, 0, sub { |
133 | $_[0] >= 0 or die "read error: $!"; |
480 | $_[0] > 0 or die "read error: $!"; |
134 | print "read <$buffer>\n"; |
481 | print "read $_[0] bytes: <$buffer>\n"; |
135 | }; |
482 | }; |
136 | |
483 | |
|
|
484 | |
|
|
485 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
|
|
486 | |
|
|
487 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
|
|
488 | reading at byte offset C<$in_offset>, and starts writing at the current |
|
|
489 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
|
|
490 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
|
|
491 | other. The same C<$in_fh> works fine though, as this function does not |
|
|
492 | move or use the file offset of C<$in_fh>. |
|
|
493 | |
|
|
494 | Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than |
|
|
495 | are written, and there is no way to find out how many more bytes have been |
|
|
496 | read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the |
|
|
497 | number of bytes written to C<$out_fh>. Only if the result value equals |
|
|
498 | C<$length> one can assume that C<$length> bytes have been read. |
|
|
499 | |
|
|
500 | Unlike with other C<aio_> functions, it makes a lot of sense to use |
|
|
501 | C<aio_sendfile> on non-blocking sockets, as long as one end (typically |
|
|
502 | the C<$in_fh>) is a file - the file I/O will then be asynchronous, while |
|
|
503 | the socket I/O will be non-blocking. Note, however, that you can run |
|
|
504 | into a trap where C<aio_sendfile> reads some data with readahead, then |
|
|
505 | fails to write all data, and when the socket is ready the next time, the |
|
|
506 | data in the cache is already lost, forcing C<aio_sendfile> to again hit |
|
|
507 | the disk. Explicit C<aio_read> + C<aio_write> let's you better control |
|
|
508 | resource usage. |
|
|
509 | |
|
|
510 | This call tries to make use of a native C<sendfile>-like syscall to |
|
|
511 | provide zero-copy operation. For this to work, C<$out_fh> should refer to |
|
|
512 | a socket, and C<$in_fh> should refer to an mmap'able file. |
|
|
513 | |
|
|
514 | If a native sendfile cannot be found or it fails with C<ENOSYS>, |
|
|
515 | C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or |
|
|
516 | C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any |
|
|
517 | type of filehandle regardless of the limitations of the operating system. |
|
|
518 | |
|
|
519 | As native sendfile syscalls (as practically any non-POSIX interface hacked |
|
|
520 | together in a hurry to improve benchmark numbers) tend to be rather buggy |
|
|
521 | on many systems, this implementation tries to work around some known bugs |
|
|
522 | in Linux and FreeBSD kernels (probably others, too), but that might fail, |
|
|
523 | so you really really should check the return value of C<aio_sendfile> - |
|
|
524 | fewer bytes than expected might have been transferred. |
|
|
525 | |
|
|
526 | |
137 | =item aio_readahead $fh,$offset,$length, $callback |
527 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
138 | |
528 | |
139 | Asynchronously reads the specified byte range into the page cache, using |
|
|
140 | the C<readahead> syscall. If that syscall doesn't exist the status will be |
|
|
141 | C<-1> and C<$!> is set to ENOSYS. |
|
|
142 | |
|
|
143 | readahead() populates the page cache with data from a file so that |
529 | C<aio_readahead> populates the page cache with data from a file so that |
144 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
530 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
145 | argument specifies the starting point from which data is to be read and |
531 | argument specifies the starting point from which data is to be read and |
146 | C<$length> specifies the number of bytes to be read. I/O is performed in |
532 | C<$length> specifies the number of bytes to be read. I/O is performed in |
147 | whole pages, so that offset is effectively rounded down to a page boundary |
533 | whole pages, so that offset is effectively rounded down to a page boundary |
148 | and bytes are read up to the next page boundary greater than or equal to |
534 | and bytes are read up to the next page boundary greater than or equal to |
149 | (off-set+length). aio_readahead() does not read beyond the end of the |
535 | (off-set+length). C<aio_readahead> does not read beyond the end of the |
150 | file. The current file offset of the file is left unchanged. |
536 | file. The current file offset of the file is left unchanged. |
151 | |
537 | |
|
|
538 | If that syscall doesn't exist (likely if your kernel isn't Linux) it will |
|
|
539 | be emulated by simply reading the data, which would have a similar effect. |
|
|
540 | |
|
|
541 | |
152 | =item aio_stat $fh_or_path, $callback |
542 | =item aio_stat $fh_or_path, $callback->($status) |
153 | |
543 | |
154 | =item aio_lstat $fh, $callback |
544 | =item aio_lstat $fh, $callback->($status) |
155 | |
545 | |
156 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
546 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
157 | be called after the stat and the results will be available using C<stat _> |
547 | be called after the stat and the results will be available using C<stat _> |
158 | or C<-s _> etc... |
548 | or C<-s _> etc... |
159 | |
549 | |
… | |
… | |
161 | for an explanation. |
551 | for an explanation. |
162 | |
552 | |
163 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
553 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
164 | error when stat'ing a large file, the results will be silently truncated |
554 | error when stat'ing a large file, the results will be silently truncated |
165 | unless perl itself is compiled with large file support. |
555 | unless perl itself is compiled with large file support. |
|
|
556 | |
|
|
557 | To help interpret the mode and dev/rdev stat values, IO::AIO offers the |
|
|
558 | following constants and functions (if not implemented, the constants will |
|
|
559 | be C<0> and the functions will either C<croak> or fall back on traditional |
|
|
560 | behaviour). |
|
|
561 | |
|
|
562 | C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, |
|
|
563 | C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, |
|
|
564 | C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. |
|
|
565 | |
|
|
566 | To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME |
|
|
567 | ACCESS>. |
166 | |
568 | |
167 | Example: Print the length of F</etc/passwd>: |
569 | Example: Print the length of F</etc/passwd>: |
168 | |
570 | |
169 | aio_stat "/etc/passwd", sub { |
571 | aio_stat "/etc/passwd", sub { |
170 | $_[0] and die "stat failed: $!"; |
572 | $_[0] and die "stat failed: $!"; |
171 | print "size is ", -s _, "\n"; |
573 | print "size is ", -s _, "\n"; |
172 | }; |
574 | }; |
173 | |
575 | |
|
|
576 | |
|
|
577 | =item aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
578 | |
|
|
579 | Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on |
|
|
580 | whether a file handle or path was passed. |
|
|
581 | |
|
|
582 | On success, the callback is passed a hash reference with the following |
|
|
583 | members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>, |
|
|
584 | C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef> |
|
|
585 | is passed. |
|
|
586 | |
|
|
587 | The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and |
|
|
588 | C<ST_NOSUID>. |
|
|
589 | |
|
|
590 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
|
|
591 | their correct value when available, or to C<0> on systems that do |
|
|
592 | not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>, |
|
|
593 | C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>, |
|
|
594 | C<ST_NODIRATIME> and C<ST_RELATIME>. |
|
|
595 | |
|
|
596 | Example: stat C</wd> and dump out the data if successful. |
|
|
597 | |
|
|
598 | aio_statvfs "/wd", sub { |
|
|
599 | my $f = $_[0] |
|
|
600 | or die "statvfs: $!"; |
|
|
601 | |
|
|
602 | use Data::Dumper; |
|
|
603 | say Dumper $f; |
|
|
604 | }; |
|
|
605 | |
|
|
606 | # result: |
|
|
607 | { |
|
|
608 | bsize => 1024, |
|
|
609 | bfree => 4333064312, |
|
|
610 | blocks => 10253828096, |
|
|
611 | files => 2050765568, |
|
|
612 | flag => 4096, |
|
|
613 | favail => 2042092649, |
|
|
614 | bavail => 4333064312, |
|
|
615 | ffree => 2042092649, |
|
|
616 | namemax => 255, |
|
|
617 | frsize => 1024, |
|
|
618 | fsid => 1810 |
|
|
619 | } |
|
|
620 | |
|
|
621 | =item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
|
|
622 | |
|
|
623 | Works like perl's C<utime> function (including the special case of $atime |
|
|
624 | and $mtime being undef). Fractional times are supported if the underlying |
|
|
625 | syscalls support them. |
|
|
626 | |
|
|
627 | When called with a pathname, uses utimes(2) if available, otherwise |
|
|
628 | utime(2). If called on a file descriptor, uses futimes(2) if available, |
|
|
629 | otherwise returns ENOSYS, so this is not portable. |
|
|
630 | |
|
|
631 | Examples: |
|
|
632 | |
|
|
633 | # set atime and mtime to current time (basically touch(1)): |
|
|
634 | aio_utime "path", undef, undef; |
|
|
635 | # set atime to current time and mtime to beginning of the epoch: |
|
|
636 | aio_utime "path", time, undef; # undef==0 |
|
|
637 | |
|
|
638 | |
|
|
639 | =item aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
|
|
640 | |
|
|
641 | Works like perl's C<chown> function, except that C<undef> for either $uid |
|
|
642 | or $gid is being interpreted as "do not change" (but -1 can also be used). |
|
|
643 | |
|
|
644 | Examples: |
|
|
645 | |
|
|
646 | # same as "chown root path" in the shell: |
|
|
647 | aio_chown "path", 0, -1; |
|
|
648 | # same as above: |
|
|
649 | aio_chown "path", 0, undef; |
|
|
650 | |
|
|
651 | |
|
|
652 | =item aio_truncate $fh_or_path, $offset, $callback->($status) |
|
|
653 | |
|
|
654 | Works like truncate(2) or ftruncate(2). |
|
|
655 | |
|
|
656 | |
|
|
657 | =item aio_allocate $fh, $mode, $offset, $len, $callback->($status) |
|
|
658 | |
|
|
659 | Allocates or frees disk space according to the C<$mode> argument. See the |
|
|
660 | linux C<fallocate> documentation for details. |
|
|
661 | |
|
|
662 | C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate |
|
|
663 | space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>, |
|
|
664 | to deallocate a file range. |
|
|
665 | |
|
|
666 | IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range |
|
|
667 | (without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range, |
|
|
668 | C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE> |
|
|
669 | to unshare shared blocks (see your L<fallocate(2)> manpage). |
|
|
670 | |
|
|
671 | The file system block size used by C<fallocate> is presumably the |
|
|
672 | C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes |
|
|
673 | can dictate other limitations. |
|
|
674 | |
|
|
675 | If C<fallocate> isn't available or cannot be emulated (currently no |
|
|
676 | emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. |
|
|
677 | |
|
|
678 | |
|
|
679 | =item aio_chmod $fh_or_path, $mode, $callback->($status) |
|
|
680 | |
|
|
681 | Works like perl's C<chmod> function. |
|
|
682 | |
|
|
683 | |
174 | =item aio_unlink $pathname, $callback |
684 | =item aio_unlink $pathname, $callback->($status) |
175 | |
685 | |
176 | Asynchronously unlink (delete) a file and call the callback with the |
686 | Asynchronously unlink (delete) a file and call the callback with the |
177 | result code. |
687 | result code. |
178 | |
688 | |
|
|
689 | |
|
|
690 | =item aio_mknod $pathname, $mode, $dev, $callback->($status) |
|
|
691 | |
|
|
692 | [EXPERIMENTAL] |
|
|
693 | |
|
|
694 | Asynchronously create a device node (or fifo). See mknod(2). |
|
|
695 | |
|
|
696 | The only (POSIX-) portable way of calling this function is: |
|
|
697 | |
|
|
698 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
699 | |
|
|
700 | See C<aio_stat> for info about some potentially helpful extra constants |
|
|
701 | and functions. |
|
|
702 | |
|
|
703 | =item aio_link $srcpath, $dstpath, $callback->($status) |
|
|
704 | |
|
|
705 | Asynchronously create a new link to the existing object at C<$srcpath> at |
|
|
706 | the path C<$dstpath> and call the callback with the result code. |
|
|
707 | |
|
|
708 | |
|
|
709 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
710 | |
|
|
711 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
|
|
712 | the path C<$dstpath> and call the callback with the result code. |
|
|
713 | |
|
|
714 | |
|
|
715 | =item aio_readlink $pathname, $callback->($link) |
|
|
716 | |
|
|
717 | Asynchronously read the symlink specified by C<$path> and pass it to |
|
|
718 | the callback. If an error occurs, nothing or undef gets passed to the |
|
|
719 | callback. |
|
|
720 | |
|
|
721 | |
|
|
722 | =item aio_realpath $pathname, $callback->($path) |
|
|
723 | |
|
|
724 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
725 | C<$path>. The resulting path only consists of directories (same as |
|
|
726 | L<Cwd::realpath>). |
|
|
727 | |
|
|
728 | This request can be used to get the absolute path of the current working |
|
|
729 | directory by passing it a path of F<.> (a single dot). |
|
|
730 | |
|
|
731 | |
|
|
732 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
733 | |
|
|
734 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
|
|
735 | rename(2) and call the callback with the result code. |
|
|
736 | |
|
|
737 | On systems that support the AIO::WD working directory abstraction |
|
|
738 | natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead |
|
|
739 | of failing, C<rename> is called on the absolute path of C<$wd>. |
|
|
740 | |
|
|
741 | |
|
|
742 | =item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status) |
|
|
743 | |
|
|
744 | Basically a version of C<aio_rename> with an additional C<$flags> |
|
|
745 | argument. Calling this with C<$flags=0> is the same as calling |
|
|
746 | C<aio_rename>. |
|
|
747 | |
|
|
748 | Non-zero flags are currently only supported on GNU/Linux systems that |
|
|
749 | support renameat2. Other systems fail with C<ENOSYS> in this case. |
|
|
750 | |
|
|
751 | The following constants are available (missing ones are, as usual C<0>), |
|
|
752 | see renameat2(2) for details: |
|
|
753 | |
|
|
754 | C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE> |
|
|
755 | and C<IO::AIO::RENAME_WHITEOUT>. |
|
|
756 | |
|
|
757 | |
|
|
758 | =item aio_mkdir $pathname, $mode, $callback->($status) |
|
|
759 | |
|
|
760 | Asynchronously mkdir (create) a directory and call the callback with |
|
|
761 | the result code. C<$mode> will be modified by the umask at the time the |
|
|
762 | request is executed, so do not change your umask. |
|
|
763 | |
|
|
764 | |
|
|
765 | =item aio_rmdir $pathname, $callback->($status) |
|
|
766 | |
|
|
767 | Asynchronously rmdir (delete) a directory and call the callback with the |
|
|
768 | result code. |
|
|
769 | |
|
|
770 | On systems that support the AIO::WD working directory abstraction |
|
|
771 | natively, the case C<[$wd, "."]> is specialcased - instead of failing, |
|
|
772 | C<rmdir> is called on the absolute path of C<$wd>. |
|
|
773 | |
|
|
774 | |
|
|
775 | =item aio_readdir $pathname, $callback->($entries) |
|
|
776 | |
|
|
777 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
|
|
778 | directory (i.e. opendir + readdir + closedir). The entries will not be |
|
|
779 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
|
|
780 | |
|
|
781 | The callback is passed a single argument which is either C<undef> or an |
|
|
782 | array-ref with the filenames. |
|
|
783 | |
|
|
784 | |
|
|
785 | =item aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
786 | |
|
|
787 | Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to |
|
|
788 | tune behaviour and output format. In case of an error, C<$entries> will be |
|
|
789 | C<undef>. |
|
|
790 | |
|
|
791 | The flags are a combination of the following constants, ORed together (the |
|
|
792 | flags will also be passed to the callback, possibly modified): |
|
|
793 | |
|
|
794 | =over 4 |
|
|
795 | |
|
|
796 | =item IO::AIO::READDIR_DENTS |
|
|
797 | |
|
|
798 | Normally the callback gets an arrayref consisting of names only (as |
|
|
799 | with C<aio_readdir>). If this flag is set, then the callback gets an |
|
|
800 | arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a |
|
|
801 | single directory entry in more detail: |
|
|
802 | |
|
|
803 | C<$name> is the name of the entry. |
|
|
804 | |
|
|
805 | C<$type> is one of the C<IO::AIO::DT_xxx> constants: |
|
|
806 | |
|
|
807 | C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, |
|
|
808 | C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, |
|
|
809 | C<IO::AIO::DT_WHT>. |
|
|
810 | |
|
|
811 | C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need |
|
|
812 | to know, you have to run stat yourself. Also, for speed/memory reasons, |
|
|
813 | the C<$type> scalars are read-only: you must not modify them. |
|
|
814 | |
|
|
815 | C<$inode> is the inode number (which might not be exact on systems with 64 |
|
|
816 | bit inode numbers and 32 bit perls). This field has unspecified content on |
|
|
817 | systems that do not deliver the inode information. |
|
|
818 | |
|
|
819 | =item IO::AIO::READDIR_DIRS_FIRST |
|
|
820 | |
|
|
821 | When this flag is set, then the names will be returned in an order where |
|
|
822 | likely directories come first, in optimal stat order. This is useful when |
|
|
823 | you need to quickly find directories, or you want to find all directories |
|
|
824 | while avoiding to stat() each entry. |
|
|
825 | |
|
|
826 | If the system returns type information in readdir, then this is used |
|
|
827 | to find directories directly. Otherwise, likely directories are names |
|
|
828 | beginning with ".", or otherwise names with no dots, of which names with |
|
|
829 | short names are tried first. |
|
|
830 | |
|
|
831 | =item IO::AIO::READDIR_STAT_ORDER |
|
|
832 | |
|
|
833 | When this flag is set, then the names will be returned in an order |
|
|
834 | suitable for stat()'ing each one. That is, when you plan to stat() most or |
|
|
835 | all files in the given directory, then the returned order will likely be |
|
|
836 | faster. |
|
|
837 | |
|
|
838 | If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, |
|
|
839 | then the likely dirs come first, resulting in a less optimal stat order |
|
|
840 | for stat'ing all entries, but likely a more optimal order for finding |
|
|
841 | subdirectories. |
|
|
842 | |
|
|
843 | =item IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
844 | |
|
|
845 | This flag should not be set when calling C<aio_readdirx>. Instead, it |
|
|
846 | is being set by C<aio_readdirx>, when any of the C<$type>'s found were |
|
|
847 | C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all |
|
|
848 | C<$type>'s are known, which can be used to speed up some algorithms. |
|
|
849 | |
|
|
850 | =back |
|
|
851 | |
|
|
852 | |
|
|
853 | =item aio_slurp $pathname, $offset, $length, $data, $callback->($status) |
|
|
854 | |
|
|
855 | Opens, reads and closes the given file. The data is put into C<$data>, |
|
|
856 | which is resized as required. |
|
|
857 | |
|
|
858 | If C<$offset> is negative, then it is counted from the end of the file. |
|
|
859 | |
|
|
860 | If C<$length> is zero, then the remaining length of the file is |
|
|
861 | used. Also, in this case, the same limitations to modifying C<$data> apply |
|
|
862 | as when IO::AIO::mmap is used, i.e. it must only be modified in-place |
|
|
863 | with C<substr>. If the size of the file is known, specifying a non-zero |
|
|
864 | C<$length> results in a performance advantage. |
|
|
865 | |
|
|
866 | This request is similar to the older C<aio_load> request, but since it is |
|
|
867 | a single request, it might be more efficient to use. |
|
|
868 | |
|
|
869 | Example: load F</etc/passwd> into C<$passwd>. |
|
|
870 | |
|
|
871 | my $passwd; |
|
|
872 | aio_slurp "/etc/passwd", 0, 0, $passwd, sub { |
|
|
873 | $_[0] >= 0 |
|
|
874 | or die "/etc/passwd: $!\n"; |
|
|
875 | |
|
|
876 | printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd; |
|
|
877 | print $passwd; |
|
|
878 | }; |
|
|
879 | IO::AIO::flush; |
|
|
880 | |
|
|
881 | |
|
|
882 | =item aio_load $pathname, $data, $callback->($status) |
|
|
883 | |
|
|
884 | This is a composite request that tries to fully load the given file into |
|
|
885 | memory. Status is the same as with aio_read. |
|
|
886 | |
|
|
887 | Using C<aio_slurp> might be more efficient, as it is a single request. |
|
|
888 | |
|
|
889 | =cut |
|
|
890 | |
|
|
891 | sub aio_load($$;$) { |
|
|
892 | my ($path, undef, $cb) = @_; |
|
|
893 | my $data = \$_[1]; |
|
|
894 | |
|
|
895 | my $pri = aioreq_pri; |
|
|
896 | my $grp = aio_group $cb; |
|
|
897 | |
|
|
898 | aioreq_pri $pri; |
|
|
899 | add $grp aio_open $path, O_RDONLY, 0, sub { |
|
|
900 | my $fh = shift |
|
|
901 | or return $grp->result (-1); |
|
|
902 | |
|
|
903 | aioreq_pri $pri; |
|
|
904 | add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { |
|
|
905 | $grp->result ($_[0]); |
|
|
906 | }; |
|
|
907 | }; |
|
|
908 | |
|
|
909 | $grp |
|
|
910 | } |
|
|
911 | |
|
|
912 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
913 | |
|
|
914 | Try to copy the I<file> (directories not supported as either source or |
|
|
915 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
916 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
|
|
917 | |
|
|
918 | Existing destination files will be truncated. |
|
|
919 | |
|
|
920 | This is a composite request that creates the destination file with |
|
|
921 | mode 0200 and copies the contents of the source file into it using |
|
|
922 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
|
|
923 | uid/gid, in that order. |
|
|
924 | |
|
|
925 | If an error occurs, the partial destination file will be unlinked, if |
|
|
926 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
927 | errors are being ignored. |
|
|
928 | |
|
|
929 | =cut |
|
|
930 | |
|
|
931 | sub aio_copy($$;$) { |
|
|
932 | my ($src, $dst, $cb) = @_; |
|
|
933 | |
|
|
934 | my $pri = aioreq_pri; |
|
|
935 | my $grp = aio_group $cb; |
|
|
936 | |
|
|
937 | aioreq_pri $pri; |
|
|
938 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
939 | if (my $src_fh = $_[0]) { |
|
|
940 | my @stat = stat $src_fh; # hmm, might block over nfs? |
|
|
941 | |
|
|
942 | aioreq_pri $pri; |
|
|
943 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
944 | if (my $dst_fh = $_[0]) { |
|
|
945 | aioreq_pri $pri; |
|
|
946 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
947 | if ($_[0] == $stat[7]) { |
|
|
948 | $grp->result (0); |
|
|
949 | close $src_fh; |
|
|
950 | |
|
|
951 | my $ch = sub { |
|
|
952 | aioreq_pri $pri; |
|
|
953 | add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub { |
|
|
954 | aioreq_pri $pri; |
|
|
955 | add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub { |
|
|
956 | aioreq_pri $pri; |
|
|
957 | add $grp aio_close $dst_fh; |
|
|
958 | } |
|
|
959 | }; |
|
|
960 | }; |
|
|
961 | |
|
|
962 | aioreq_pri $pri; |
|
|
963 | add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub { |
|
|
964 | if ($_[0] < 0 && $! == ENOSYS) { |
|
|
965 | aioreq_pri $pri; |
|
|
966 | add $grp aio_utime $dst, $stat[8], $stat[9], $ch; |
|
|
967 | } else { |
|
|
968 | $ch->(); |
|
|
969 | } |
|
|
970 | }; |
|
|
971 | } else { |
|
|
972 | $grp->result (-1); |
|
|
973 | close $src_fh; |
|
|
974 | close $dst_fh; |
|
|
975 | |
|
|
976 | aioreq $pri; |
|
|
977 | add $grp aio_unlink $dst; |
|
|
978 | } |
|
|
979 | }; |
|
|
980 | } else { |
|
|
981 | $grp->result (-1); |
|
|
982 | } |
|
|
983 | }, |
|
|
984 | |
|
|
985 | } else { |
|
|
986 | $grp->result (-1); |
|
|
987 | } |
|
|
988 | }; |
|
|
989 | |
|
|
990 | $grp |
|
|
991 | } |
|
|
992 | |
|
|
993 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
994 | |
|
|
995 | Try to move the I<file> (directories not supported as either source or |
|
|
996 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
997 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
|
|
998 | |
|
|
999 | This is a composite request that tries to rename(2) the file first; if |
|
|
1000 | rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
1001 | that is successful, unlinks the C<$srcpath>. |
|
|
1002 | |
|
|
1003 | =cut |
|
|
1004 | |
|
|
1005 | sub aio_move($$;$) { |
|
|
1006 | my ($src, $dst, $cb) = @_; |
|
|
1007 | |
|
|
1008 | my $pri = aioreq_pri; |
|
|
1009 | my $grp = aio_group $cb; |
|
|
1010 | |
|
|
1011 | aioreq_pri $pri; |
|
|
1012 | add $grp aio_rename $src, $dst, sub { |
|
|
1013 | if ($_[0] && $! == EXDEV) { |
|
|
1014 | aioreq_pri $pri; |
|
|
1015 | add $grp aio_copy $src, $dst, sub { |
|
|
1016 | $grp->result ($_[0]); |
|
|
1017 | |
|
|
1018 | unless ($_[0]) { |
|
|
1019 | aioreq_pri $pri; |
|
|
1020 | add $grp aio_unlink $src; |
|
|
1021 | } |
|
|
1022 | }; |
|
|
1023 | } else { |
|
|
1024 | $grp->result ($_[0]); |
|
|
1025 | } |
|
|
1026 | }; |
|
|
1027 | |
|
|
1028 | $grp |
|
|
1029 | } |
|
|
1030 | |
|
|
1031 | =item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
|
|
1032 | |
|
|
1033 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
|
|
1034 | efficiently separate the entries of directory C<$path> into two sets of |
|
|
1035 | names, directories you can recurse into (directories), and ones you cannot |
|
|
1036 | recurse into (everything else, including symlinks to directories). |
|
|
1037 | |
|
|
1038 | C<aio_scandir> is a composite request that generates many sub requests. |
|
|
1039 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
|
|
1040 | this function generates. If it is C<< <= 0 >>, then a suitable default |
|
|
1041 | will be chosen (currently 4). |
|
|
1042 | |
|
|
1043 | On error, the callback is called without arguments, otherwise it receives |
|
|
1044 | two array-refs with path-relative entry names. |
|
|
1045 | |
|
|
1046 | Example: |
|
|
1047 | |
|
|
1048 | aio_scandir $dir, 0, sub { |
|
|
1049 | my ($dirs, $nondirs) = @_; |
|
|
1050 | print "real directories: @$dirs\n"; |
|
|
1051 | print "everything else: @$nondirs\n"; |
|
|
1052 | }; |
|
|
1053 | |
|
|
1054 | Implementation notes. |
|
|
1055 | |
|
|
1056 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
|
|
1057 | |
|
|
1058 | If readdir returns file type information, then this is used directly to |
|
|
1059 | find directories. |
|
|
1060 | |
|
|
1061 | Otherwise, after reading the directory, the modification time, size etc. |
|
|
1062 | of the directory before and after the readdir is checked, and if they |
|
|
1063 | match (and isn't the current time), the link count will be used to decide |
|
|
1064 | how many entries are directories (if >= 2). Otherwise, no knowledge of the |
|
|
1065 | number of subdirectories will be assumed. |
|
|
1066 | |
|
|
1067 | Then entries will be sorted into likely directories a non-initial dot |
|
|
1068 | currently) and likely non-directories (see C<aio_readdirx>). Then every |
|
|
1069 | entry plus an appended C</.> will be C<stat>'ed, likely directories first, |
|
|
1070 | in order of their inode numbers. If that succeeds, it assumes that the |
|
|
1071 | entry is a directory or a symlink to directory (which will be checked |
|
|
1072 | separately). This is often faster than stat'ing the entry itself because |
|
|
1073 | filesystems might detect the type of the entry without reading the inode |
|
|
1074 | data (e.g. ext2fs filetype feature), even on systems that cannot return |
|
|
1075 | the filetype information on readdir. |
|
|
1076 | |
|
|
1077 | If the known number of directories (link count - 2) has been reached, the |
|
|
1078 | rest of the entries is assumed to be non-directories. |
|
|
1079 | |
|
|
1080 | This only works with certainty on POSIX (= UNIX) filesystems, which |
|
|
1081 | fortunately are the vast majority of filesystems around. |
|
|
1082 | |
|
|
1083 | It will also likely work on non-POSIX filesystems with reduced efficiency |
|
|
1084 | as those tend to return 0 or 1 as link counts, which disables the |
|
|
1085 | directory counting heuristic. |
|
|
1086 | |
|
|
1087 | =cut |
|
|
1088 | |
|
|
1089 | sub aio_scandir($$;$) { |
|
|
1090 | my ($path, $maxreq, $cb) = @_; |
|
|
1091 | |
|
|
1092 | my $pri = aioreq_pri; |
|
|
1093 | |
|
|
1094 | my $grp = aio_group $cb; |
|
|
1095 | |
|
|
1096 | $maxreq = 4 if $maxreq <= 0; |
|
|
1097 | |
|
|
1098 | # get a wd object |
|
|
1099 | aioreq_pri $pri; |
|
|
1100 | add $grp aio_wd $path, sub { |
|
|
1101 | $_[0] |
|
|
1102 | or return $grp->result (); |
|
|
1103 | |
|
|
1104 | my $wd = [shift, "."]; |
|
|
1105 | |
|
|
1106 | # stat once |
|
|
1107 | aioreq_pri $pri; |
|
|
1108 | add $grp aio_stat $wd, sub { |
|
|
1109 | return $grp->result () if $_[0]; |
|
|
1110 | my $now = time; |
|
|
1111 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
1112 | |
|
|
1113 | # read the directory entries |
|
|
1114 | aioreq_pri $pri; |
|
|
1115 | add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { |
|
|
1116 | my $entries = shift |
|
|
1117 | or return $grp->result (); |
|
|
1118 | |
|
|
1119 | # stat the dir another time |
|
|
1120 | aioreq_pri $pri; |
|
|
1121 | add $grp aio_stat $wd, sub { |
|
|
1122 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
|
|
1123 | |
|
|
1124 | my $ndirs; |
|
|
1125 | |
|
|
1126 | # take the slow route if anything looks fishy |
|
|
1127 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
|
|
1128 | $ndirs = -1; |
|
|
1129 | } else { |
|
|
1130 | # if nlink == 2, we are finished |
|
|
1131 | # for non-posix-fs's, we rely on nlink < 2 |
|
|
1132 | $ndirs = (stat _)[3] - 2 |
|
|
1133 | or return $grp->result ([], $entries); |
|
|
1134 | } |
|
|
1135 | |
|
|
1136 | my (@dirs, @nondirs); |
|
|
1137 | |
|
|
1138 | my $statgrp = add $grp aio_group sub { |
|
|
1139 | $grp->result (\@dirs, \@nondirs); |
|
|
1140 | }; |
|
|
1141 | |
|
|
1142 | limit $statgrp $maxreq; |
|
|
1143 | feed $statgrp sub { |
|
|
1144 | return unless @$entries; |
|
|
1145 | my $entry = shift @$entries; |
|
|
1146 | |
|
|
1147 | aioreq_pri $pri; |
|
|
1148 | $wd->[1] = "$entry/."; |
|
|
1149 | add $statgrp aio_stat $wd, sub { |
|
|
1150 | if ($_[0] < 0) { |
|
|
1151 | push @nondirs, $entry; |
|
|
1152 | } else { |
|
|
1153 | # need to check for real directory |
|
|
1154 | aioreq_pri $pri; |
|
|
1155 | $wd->[1] = $entry; |
|
|
1156 | add $statgrp aio_lstat $wd, sub { |
|
|
1157 | if (-d _) { |
|
|
1158 | push @dirs, $entry; |
|
|
1159 | |
|
|
1160 | unless (--$ndirs) { |
|
|
1161 | push @nondirs, @$entries; |
|
|
1162 | feed $statgrp; |
|
|
1163 | } |
|
|
1164 | } else { |
|
|
1165 | push @nondirs, $entry; |
|
|
1166 | } |
|
|
1167 | } |
|
|
1168 | } |
|
|
1169 | }; |
|
|
1170 | }; |
|
|
1171 | }; |
|
|
1172 | }; |
|
|
1173 | }; |
|
|
1174 | }; |
|
|
1175 | |
|
|
1176 | $grp |
|
|
1177 | } |
|
|
1178 | |
|
|
1179 | =item aio_rmtree $pathname, $callback->($status) |
|
|
1180 | |
|
|
1181 | Delete a directory tree starting (and including) C<$path>, return the |
|
|
1182 | status of the final C<rmdir> only. This is a composite request that |
|
|
1183 | uses C<aio_scandir> to recurse into and rmdir directories, and unlink |
|
|
1184 | everything else. |
|
|
1185 | |
|
|
1186 | =cut |
|
|
1187 | |
|
|
1188 | sub aio_rmtree; |
|
|
1189 | sub aio_rmtree($;$) { |
|
|
1190 | my ($path, $cb) = @_; |
|
|
1191 | |
|
|
1192 | my $pri = aioreq_pri; |
|
|
1193 | my $grp = aio_group $cb; |
|
|
1194 | |
|
|
1195 | aioreq_pri $pri; |
|
|
1196 | add $grp aio_scandir $path, 0, sub { |
|
|
1197 | my ($dirs, $nondirs) = @_; |
|
|
1198 | |
|
|
1199 | my $dirgrp = aio_group sub { |
|
|
1200 | add $grp aio_rmdir $path, sub { |
|
|
1201 | $grp->result ($_[0]); |
|
|
1202 | }; |
|
|
1203 | }; |
|
|
1204 | |
|
|
1205 | (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs; |
|
|
1206 | (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs; |
|
|
1207 | |
|
|
1208 | add $grp $dirgrp; |
|
|
1209 | }; |
|
|
1210 | |
|
|
1211 | $grp |
|
|
1212 | } |
|
|
1213 | |
|
|
1214 | =item aio_fcntl $fh, $cmd, $arg, $callback->($status) |
|
|
1215 | |
|
|
1216 | =item aio_ioctl $fh, $request, $buf, $callback->($status) |
|
|
1217 | |
|
|
1218 | These work just like the C<fcntl> and C<ioctl> built-in functions, except |
|
|
1219 | they execute asynchronously and pass the return value to the callback. |
|
|
1220 | |
|
|
1221 | Both calls can be used for a lot of things, some of which make more sense |
|
|
1222 | to run asynchronously in their own thread, while some others make less |
|
|
1223 | sense. For example, calls that block waiting for external events, such |
|
|
1224 | as locking, will also lock down an I/O thread while it is waiting, which |
|
|
1225 | can deadlock the whole I/O system. At the same time, there might be no |
|
|
1226 | alternative to using a thread to wait. |
|
|
1227 | |
|
|
1228 | So in general, you should only use these calls for things that do |
|
|
1229 | (filesystem) I/O, not for things that wait for other events (network, |
|
|
1230 | other processes), although if you are careful and know what you are doing, |
|
|
1231 | you still can. |
|
|
1232 | |
|
|
1233 | The following constants are available (missing ones are, as usual C<0>): |
|
|
1234 | |
|
|
1235 | C<F_DUPFD_CLOEXEC>, |
|
|
1236 | |
|
|
1237 | C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>, |
|
|
1238 | |
|
|
1239 | C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>. |
|
|
1240 | |
|
|
1241 | C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>, |
|
|
1242 | C<FS_IOC_FIEMAP>. |
|
|
1243 | |
|
|
1244 | C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>, |
|
|
1245 | C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>. |
|
|
1246 | |
|
|
1247 | C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>, |
|
|
1248 | C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>, |
|
|
1249 | C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>, |
|
|
1250 | C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>, |
|
|
1251 | C<FS_FL_USER_MODIFIABLE>. |
|
|
1252 | |
|
|
1253 | C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>, |
|
|
1254 | C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>, |
|
|
1255 | C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>, |
|
|
1256 | C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>, |
|
|
1257 | |
|
|
1258 | =item aio_sync $callback->($status) |
|
|
1259 | |
|
|
1260 | Asynchronously call sync and call the callback when finished. |
|
|
1261 | |
179 | =item aio_fsync $fh, $callback |
1262 | =item aio_fsync $fh, $callback->($status) |
180 | |
1263 | |
181 | Asynchronously call fsync on the given filehandle and call the callback |
1264 | Asynchronously call fsync on the given filehandle and call the callback |
182 | with the fsync result code. |
1265 | with the fsync result code. |
183 | |
1266 | |
184 | =item aio_fdatasync $fh, $callback |
1267 | =item aio_fdatasync $fh, $callback->($status) |
185 | |
1268 | |
186 | Asynchronously call fdatasync on the given filehandle and call the |
1269 | Asynchronously call fdatasync on the given filehandle and call the |
187 | callback with the fdatasync result code. |
1270 | callback with the fdatasync result code. |
188 | |
1271 | |
|
|
1272 | If this call isn't available because your OS lacks it or it couldn't be |
|
|
1273 | detected, it will be emulated by calling C<fsync> instead. |
|
|
1274 | |
|
|
1275 | =item aio_syncfs $fh, $callback->($status) |
|
|
1276 | |
|
|
1277 | Asynchronously call the syncfs syscall to sync the filesystem associated |
|
|
1278 | to the given filehandle and call the callback with the syncfs result |
|
|
1279 | code. If syncfs is not available, calls sync(), but returns C<-1> and sets |
|
|
1280 | errno to C<ENOSYS> nevertheless. |
|
|
1281 | |
|
|
1282 | =item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
1283 | |
|
|
1284 | Sync the data portion of the file specified by C<$offset> and C<$length> |
|
|
1285 | to disk (but NOT the metadata), by calling the Linux-specific |
|
|
1286 | sync_file_range call. If sync_file_range is not available or it returns |
|
|
1287 | ENOSYS, then fdatasync or fsync is being substituted. |
|
|
1288 | |
|
|
1289 | C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, |
|
|
1290 | C<IO::AIO::SYNC_FILE_RANGE_WRITE> and |
|
|
1291 | C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range |
|
|
1292 | manpage for details. |
|
|
1293 | |
|
|
1294 | =item aio_pathsync $pathname, $callback->($status) |
|
|
1295 | |
|
|
1296 | This request tries to open, fsync and close the given path. This is a |
|
|
1297 | composite request intended to sync directories after directory operations |
|
|
1298 | (E.g. rename). This might not work on all operating systems or have any |
|
|
1299 | specific effect, but usually it makes sure that directory changes get |
|
|
1300 | written to disc. It works for anything that can be opened for read-only, |
|
|
1301 | not just directories. |
|
|
1302 | |
|
|
1303 | Future versions of this function might fall back to other methods when |
|
|
1304 | C<fsync> on the directory fails (such as calling C<sync>). |
|
|
1305 | |
|
|
1306 | Passes C<0> when everything went ok, and C<-1> on error. |
|
|
1307 | |
|
|
1308 | =cut |
|
|
1309 | |
|
|
1310 | sub aio_pathsync($;$) { |
|
|
1311 | my ($path, $cb) = @_; |
|
|
1312 | |
|
|
1313 | my $pri = aioreq_pri; |
|
|
1314 | my $grp = aio_group $cb; |
|
|
1315 | |
|
|
1316 | aioreq_pri $pri; |
|
|
1317 | add $grp aio_open $path, O_RDONLY, 0, sub { |
|
|
1318 | my ($fh) = @_; |
|
|
1319 | if ($fh) { |
|
|
1320 | aioreq_pri $pri; |
|
|
1321 | add $grp aio_fsync $fh, sub { |
|
|
1322 | $grp->result ($_[0]); |
|
|
1323 | |
|
|
1324 | aioreq_pri $pri; |
|
|
1325 | add $grp aio_close $fh; |
|
|
1326 | }; |
|
|
1327 | } else { |
|
|
1328 | $grp->result (-1); |
|
|
1329 | } |
|
|
1330 | }; |
|
|
1331 | |
|
|
1332 | $grp |
|
|
1333 | } |
|
|
1334 | |
|
|
1335 | =item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status) |
|
|
1336 | |
|
|
1337 | This is a rather advanced IO::AIO call, which only works on mmap(2)ed |
|
|
1338 | scalars (see the C<IO::AIO::mmap> function, although it also works on data |
|
|
1339 | scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the |
|
|
1340 | scalar must only be modified in-place while an aio operation is pending on |
|
|
1341 | it). |
|
|
1342 | |
|
|
1343 | It calls the C<msync> function of your OS, if available, with the memory |
|
|
1344 | area starting at C<$offset> in the string and ending C<$length> bytes |
|
|
1345 | later. If C<$length> is negative, counts from the end, and if C<$length> |
|
|
1346 | is C<undef>, then it goes till the end of the string. The flags can be |
|
|
1347 | either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional |
|
|
1348 | C<IO::AIO::MS_INVALIDATE>. |
|
|
1349 | |
|
|
1350 | =item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1351 | |
|
|
1352 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1353 | scalars. |
|
|
1354 | |
|
|
1355 | It touches (reads or writes) all memory pages in the specified |
|
|
1356 | range inside the scalar. All caveats and parameters are the same |
|
|
1357 | as for C<aio_msync>, above, except for flags, which must be either |
|
|
1358 | C<0> (which reads all pages and ensures they are instantiated) or |
|
|
1359 | C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and |
|
|
1360 | writing an octet from it, which dirties the page). |
|
|
1361 | |
|
|
1362 | =item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
1363 | |
|
|
1364 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1365 | scalars. |
|
|
1366 | |
|
|
1367 | It reads in all the pages of the underlying storage into memory (if any) |
|
|
1368 | and locks them, so they are not getting swapped/paged out or removed. |
|
|
1369 | |
|
|
1370 | If C<$length> is undefined, then the scalar will be locked till the end. |
|
|
1371 | |
|
|
1372 | On systems that do not implement C<mlock>, this function returns C<-1> |
|
|
1373 | and sets errno to C<ENOSYS>. |
|
|
1374 | |
|
|
1375 | Note that the corresponding C<munlock> is synchronous and is |
|
|
1376 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1377 | |
|
|
1378 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
1379 | C<$data> gets destroyed. |
|
|
1380 | |
|
|
1381 | open my $fh, "<", $path or die "$path: $!"; |
|
|
1382 | my $data; |
|
|
1383 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
1384 | aio_mlock $data; # mlock in background |
|
|
1385 | |
|
|
1386 | =item aio_mlockall $flags, $callback->($status) |
|
|
1387 | |
|
|
1388 | Calls the C<mlockall> function with the given C<$flags> (a combination of |
|
|
1389 | C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). |
|
|
1390 | |
|
|
1391 | On systems that do not implement C<mlockall>, this function returns C<-1> |
|
|
1392 | and sets errno to C<ENOSYS>. |
|
|
1393 | |
|
|
1394 | Note that the corresponding C<munlockall> is synchronous and is |
|
|
1395 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1396 | |
|
|
1397 | Example: asynchronously lock all current and future pages into memory. |
|
|
1398 | |
|
|
1399 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
1400 | |
|
|
1401 | =item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) |
|
|
1402 | |
|
|
1403 | Queries the extents of the given file (by calling the Linux C<FIEMAP> |
|
|
1404 | ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If |
|
|
1405 | the ioctl is not available on your OS, then this request will fail with |
|
|
1406 | C<ENOSYS>. |
|
|
1407 | |
|
|
1408 | C<$start> is the starting offset to query extents for, C<$length> is the |
|
|
1409 | size of the range to query - if it is C<undef>, then the whole file will |
|
|
1410 | be queried. |
|
|
1411 | |
|
|
1412 | C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or |
|
|
1413 | C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also |
|
|
1414 | exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query |
|
|
1415 | the data portion. |
|
|
1416 | |
|
|
1417 | C<$count> is the maximum number of extent records to return. If it is |
|
|
1418 | C<undef>, then IO::AIO queries all extents of the range. As a very special |
|
|
1419 | case, if it is C<0>, then the callback receives the number of extents |
|
|
1420 | instead of the extents themselves (which is unreliable, see below). |
|
|
1421 | |
|
|
1422 | If an error occurs, the callback receives no arguments. The special |
|
|
1423 | C<errno> value C<IO::AIO::EBADR> is available to test for flag errors. |
|
|
1424 | |
|
|
1425 | Otherwise, the callback receives an array reference with extent |
|
|
1426 | structures. Each extent structure is an array reference itself, with the |
|
|
1427 | following members: |
|
|
1428 | |
|
|
1429 | [$logical, $physical, $length, $flags] |
|
|
1430 | |
|
|
1431 | Flags is any combination of the following flag values (typically either C<0> |
|
|
1432 | or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)): |
|
|
1433 | |
|
|
1434 | C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>, |
|
|
1435 | C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>, |
|
|
1436 | C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, |
|
|
1437 | C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, |
|
|
1438 | C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or |
|
|
1439 | C<IO::AIO::FIEMAP_EXTENT_SHARED>. |
|
|
1440 | |
|
|
1441 | At the time of this writing (Linux 3.2), this request is unreliable unless |
|
|
1442 | C<$count> is C<undef>, as the kernel has all sorts of bugs preventing |
|
|
1443 | it to return all extents of a range for files with a large number of |
|
|
1444 | extents. The code (only) works around all these issues if C<$count> is |
|
|
1445 | C<undef>. |
|
|
1446 | |
|
|
1447 | =item aio_group $callback->(...) |
|
|
1448 | |
|
|
1449 | This is a very special aio request: Instead of doing something, it is a |
|
|
1450 | container for other aio requests, which is useful if you want to bundle |
|
|
1451 | many requests into a single, composite, request with a definite callback |
|
|
1452 | and the ability to cancel the whole request with its subrequests. |
|
|
1453 | |
|
|
1454 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
1455 | for more info. |
|
|
1456 | |
|
|
1457 | Example: |
|
|
1458 | |
|
|
1459 | my $grp = aio_group sub { |
|
|
1460 | print "all stats done\n"; |
|
|
1461 | }; |
|
|
1462 | |
|
|
1463 | add $grp |
|
|
1464 | (aio_stat ...), |
|
|
1465 | (aio_stat ...), |
|
|
1466 | ...; |
|
|
1467 | |
|
|
1468 | =item aio_nop $callback->() |
|
|
1469 | |
|
|
1470 | This is a special request - it does nothing in itself and is only used for |
|
|
1471 | side effects, such as when you want to add a dummy request to a group so |
|
|
1472 | that finishing the requests in the group depends on executing the given |
|
|
1473 | code. |
|
|
1474 | |
|
|
1475 | While this request does nothing, it still goes through the execution |
|
|
1476 | phase and still requires a worker thread. Thus, the callback will not |
|
|
1477 | be executed immediately but only after other requests in the queue have |
|
|
1478 | entered their execution phase. This can be used to measure request |
|
|
1479 | latency. |
|
|
1480 | |
|
|
1481 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
|
|
1482 | |
|
|
1483 | Mainly used for debugging and benchmarking, this aio request puts one of |
|
|
1484 | the request workers to sleep for the given time. |
|
|
1485 | |
|
|
1486 | While it is theoretically handy to have simple I/O scheduling requests |
|
|
1487 | like sleep and file handle readable/writable, the overhead this creates is |
|
|
1488 | immense (it blocks a thread for a long time) so do not use this function |
|
|
1489 | except to put your application under artificial I/O pressure. |
|
|
1490 | |
189 | =back |
1491 | =back |
190 | |
1492 | |
|
|
1493 | |
|
|
1494 | =head2 IO::AIO::WD - multiple working directories |
|
|
1495 | |
|
|
1496 | Your process only has one current working directory, which is used by all |
|
|
1497 | threads. This makes it hard to use relative paths (some other component |
|
|
1498 | could call C<chdir> at any time, and it is hard to control when the path |
|
|
1499 | will be used by IO::AIO). |
|
|
1500 | |
|
|
1501 | One solution for this is to always use absolute paths. This usually works, |
|
|
1502 | but can be quite slow (the kernel has to walk the whole path on every |
|
|
1503 | access), and can also be a hassle to implement. |
|
|
1504 | |
|
|
1505 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
1506 | futimensat and so on) that make it possible to specify working directories |
|
|
1507 | per operation. |
|
|
1508 | |
|
|
1509 | For portability, and because the clowns who "designed", or shall I write, |
|
|
1510 | perpetrated this new interface were obviously half-drunk, this abstraction |
|
|
1511 | cannot be perfect, though. |
|
|
1512 | |
|
|
1513 | IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD |
|
|
1514 | object. This object stores the canonicalised, absolute version of the |
|
|
1515 | path, and on systems that allow it, also a directory file descriptor. |
|
|
1516 | |
|
|
1517 | Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> |
|
|
1518 | or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD |
|
|
1519 | object and a pathname instead (or the IO::AIO::WD object alone, which |
|
|
1520 | gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the |
|
|
1521 | IO::AIO::WD object is ignored, otherwise the pathname is resolved relative |
|
|
1522 | to that IO::AIO::WD object. |
|
|
1523 | |
|
|
1524 | For example, to get a wd object for F</etc> and then stat F<passwd> |
|
|
1525 | inside, you would write: |
|
|
1526 | |
|
|
1527 | aio_wd "/etc", sub { |
|
|
1528 | my $etcdir = shift; |
|
|
1529 | |
|
|
1530 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1531 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1532 | # when $etcdir is undef. |
|
|
1533 | |
|
|
1534 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1535 | # yay |
|
|
1536 | }; |
|
|
1537 | }; |
|
|
1538 | |
|
|
1539 | The fact that C<aio_wd> is a request and not a normal function shows that |
|
|
1540 | creating an IO::AIO::WD object is itself a potentially blocking operation, |
|
|
1541 | which is why it is done asynchronously. |
|
|
1542 | |
|
|
1543 | To stat the directory obtained with C<aio_wd> above, one could write |
|
|
1544 | either of the following three request calls: |
|
|
1545 | |
|
|
1546 | aio_lstat "/etc" , sub { ... # pathname as normal string |
|
|
1547 | aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself) |
|
|
1548 | aio_lstat $wd , sub { ... # shorthand for the previous |
|
|
1549 | |
|
|
1550 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1551 | object and the pathname string, so you could write the following without |
|
|
1552 | causing any issues due to C<$path> getting reused: |
|
|
1553 | |
|
|
1554 | my $path = [$wd, undef]; |
|
|
1555 | |
|
|
1556 | for my $name (qw(abc def ghi)) { |
|
|
1557 | $path->[1] = $name; |
|
|
1558 | aio_stat $path, sub { |
|
|
1559 | # ... |
|
|
1560 | }; |
|
|
1561 | } |
|
|
1562 | |
|
|
1563 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1564 | pathname string doesn't change, so will point to the new directory (or |
|
|
1565 | nowhere at all), while the directory fd, if available on the system, |
|
|
1566 | will still point to the original directory. Most functions accepting a |
|
|
1567 | pathname will use the directory fd on newer systems, and the string on |
|
|
1568 | older systems. Some functions (such as C<aio_realpath>) will always rely on |
|
|
1569 | the string form of the pathname. |
|
|
1570 | |
|
|
1571 | So this functionality is mainly useful to get some protection against |
|
|
1572 | C<chdir>, to easily get an absolute path out of a relative path for future |
|
|
1573 | reference, and to speed up doing many operations in the same directory |
|
|
1574 | (e.g. when stat'ing all files in a directory). |
|
|
1575 | |
|
|
1576 | The following functions implement this working directory abstraction: |
|
|
1577 | |
|
|
1578 | =over 4 |
|
|
1579 | |
|
|
1580 | =item aio_wd $pathname, $callback->($wd) |
|
|
1581 | |
|
|
1582 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1583 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1584 | system, also open a directory fd to speed up pathname resolution relative |
|
|
1585 | to this working directory. |
|
|
1586 | |
|
|
1587 | If something goes wrong, then C<undef> is passwd to the callback instead |
|
|
1588 | of a working directory object and C<$!> is set appropriately. Since |
|
|
1589 | passing C<undef> as working directory component of a pathname fails the |
|
|
1590 | request with C<ENOENT>, there is often no need for error checking in the |
|
|
1591 | C<aio_wd> callback, as future requests using the value will fail in the |
|
|
1592 | expected way. |
|
|
1593 | |
|
|
1594 | =item IO::AIO::CWD |
|
|
1595 | |
|
|
1596 | This is a compiletime constant (object) that represents the process |
|
|
1597 | current working directory. |
|
|
1598 | |
|
|
1599 | Specifying this object as working directory object for a pathname is as if |
|
|
1600 | the pathname would be specified directly, without a directory object. For |
|
|
1601 | example, these calls are functionally identical: |
|
|
1602 | |
|
|
1603 | aio_stat "somefile", sub { ... }; |
|
|
1604 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1605 | |
|
|
1606 | =back |
|
|
1607 | |
|
|
1608 | To recover the path associated with an IO::AIO::WD object, you can use |
|
|
1609 | C<aio_realpath>: |
|
|
1610 | |
|
|
1611 | aio_realpath $wd, sub { |
|
|
1612 | warn "path is $_[0]\n"; |
|
|
1613 | }; |
|
|
1614 | |
|
|
1615 | Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir> |
|
|
1616 | sometimes, fall back to using an absolue path. |
|
|
1617 | |
|
|
1618 | =head2 IO::AIO::REQ CLASS |
|
|
1619 | |
|
|
1620 | All non-aggregate C<aio_*> functions return an object of this class when |
|
|
1621 | called in non-void context. |
|
|
1622 | |
|
|
1623 | =over 4 |
|
|
1624 | |
|
|
1625 | =item cancel $req |
|
|
1626 | |
|
|
1627 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
1628 | when entering the B<execute> state and skipping calling the callback when |
|
|
1629 | entering the the B<result> state, but will leave the request otherwise |
|
|
1630 | untouched (with the exception of readdir). That means that requests that |
|
|
1631 | currently execute will not be stopped and resources held by the request |
|
|
1632 | will not be freed prematurely. |
|
|
1633 | |
|
|
1634 | =item cb $req $callback->(...) |
|
|
1635 | |
|
|
1636 | Replace (or simply set) the callback registered to the request. |
|
|
1637 | |
|
|
1638 | =back |
|
|
1639 | |
|
|
1640 | =head2 IO::AIO::GRP CLASS |
|
|
1641 | |
|
|
1642 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
1643 | objects of this class, too. |
|
|
1644 | |
|
|
1645 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
1646 | aio requests. |
|
|
1647 | |
|
|
1648 | You create one by calling the C<aio_group> constructing function with a |
|
|
1649 | callback that will be called when all contained requests have entered the |
|
|
1650 | C<done> state: |
|
|
1651 | |
|
|
1652 | my $grp = aio_group sub { |
|
|
1653 | print "all requests are done\n"; |
|
|
1654 | }; |
|
|
1655 | |
|
|
1656 | You add requests by calling the C<add> method with one or more |
|
|
1657 | C<IO::AIO::REQ> objects: |
|
|
1658 | |
|
|
1659 | $grp->add (aio_unlink "..."); |
|
|
1660 | |
|
|
1661 | add $grp aio_stat "...", sub { |
|
|
1662 | $_[0] or return $grp->result ("error"); |
|
|
1663 | |
|
|
1664 | # add another request dynamically, if first succeeded |
|
|
1665 | add $grp aio_open "...", sub { |
|
|
1666 | $grp->result ("ok"); |
|
|
1667 | }; |
|
|
1668 | }; |
|
|
1669 | |
|
|
1670 | This makes it very easy to create composite requests (see the source of |
|
|
1671 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
1672 | |
|
|
1673 | =over 4 |
|
|
1674 | |
|
|
1675 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
1676 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
1677 | |
|
|
1678 | =item * They can be canceled like any other request. Canceling will cancel not |
|
|
1679 | only the request itself, but also all requests it contains. |
|
|
1680 | |
|
|
1681 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
1682 | |
|
|
1683 | =item * You must not add requests to a group from within the group callback (or |
|
|
1684 | any later time). |
|
|
1685 | |
|
|
1686 | =back |
|
|
1687 | |
|
|
1688 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
1689 | will finish very quickly. If they contain only requests that are in the |
|
|
1690 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
1691 | exist. |
|
|
1692 | |
|
|
1693 | That means after creating a group you have some time to add requests |
|
|
1694 | (precisely before the callback has been invoked, which is only done within |
|
|
1695 | the C<poll_cb>). And in the callbacks of those requests, you can add |
|
|
1696 | further requests to the group. And only when all those requests have |
|
|
1697 | finished will the the group itself finish. |
|
|
1698 | |
|
|
1699 | =over 4 |
|
|
1700 | |
|
|
1701 | =item add $grp ... |
|
|
1702 | |
|
|
1703 | =item $grp->add (...) |
|
|
1704 | |
|
|
1705 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
|
|
1706 | be added, including other groups, as long as you do not create circular |
|
|
1707 | dependencies. |
|
|
1708 | |
|
|
1709 | Returns all its arguments. |
|
|
1710 | |
|
|
1711 | =item $grp->cancel_subs |
|
|
1712 | |
|
|
1713 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
1714 | itself. Useful when you queued a lot of events but got a result early. |
|
|
1715 | |
|
|
1716 | The group request will finish normally (you cannot add requests to the |
|
|
1717 | group). |
|
|
1718 | |
|
|
1719 | =item $grp->result (...) |
|
|
1720 | |
|
|
1721 | Set the result value(s) that will be passed to the group callback when all |
|
|
1722 | subrequests have finished and set the groups errno to the current value |
|
|
1723 | of errno (just like calling C<errno> without an error number). By default, |
|
|
1724 | no argument will be passed and errno is zero. |
|
|
1725 | |
|
|
1726 | =item $grp->errno ([$errno]) |
|
|
1727 | |
|
|
1728 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
1729 | when the argument is missing. |
|
|
1730 | |
|
|
1731 | Every aio request has an associated errno value that is restored when |
|
|
1732 | the callback is invoked. This method lets you change this value from its |
|
|
1733 | default (0). |
|
|
1734 | |
|
|
1735 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
1736 | before the call to C<result>, or call c<errno> after it. |
|
|
1737 | |
|
|
1738 | =item feed $grp $callback->($grp) |
|
|
1739 | |
|
|
1740 | Sets a feeder/generator on this group: every group can have an attached |
|
|
1741 | generator that generates requests if idle. The idea behind this is that, |
|
|
1742 | although you could just queue as many requests as you want in a group, |
|
|
1743 | this might starve other requests for a potentially long time. For example, |
|
|
1744 | C<aio_scandir> might generate hundreds of thousands of C<aio_stat> |
|
|
1745 | requests, delaying any later requests for a long time. |
|
|
1746 | |
|
|
1747 | To avoid this, and allow incremental generation of requests, you can |
|
|
1748 | instead a group and set a feeder on it that generates those requests. The |
|
|
1749 | feed callback will be called whenever there are few enough (see C<limit>, |
|
|
1750 | below) requests active in the group itself and is expected to queue more |
|
|
1751 | requests. |
|
|
1752 | |
|
|
1753 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
|
|
1754 | not impose any limits). |
|
|
1755 | |
|
|
1756 | If the feed does not queue more requests when called, it will be |
|
|
1757 | automatically removed from the group. |
|
|
1758 | |
|
|
1759 | If the feed limit is C<0> when this method is called, it will be set to |
|
|
1760 | C<2> automatically. |
|
|
1761 | |
|
|
1762 | Example: |
|
|
1763 | |
|
|
1764 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
1765 | |
|
|
1766 | my $grp = aio_group sub { print "finished\n" }; |
|
|
1767 | limit $grp 4; |
|
|
1768 | feed $grp sub { |
|
|
1769 | my $file = pop @files |
|
|
1770 | or return; |
|
|
1771 | |
|
|
1772 | add $grp aio_stat $file, sub { ... }; |
|
|
1773 | }; |
|
|
1774 | |
|
|
1775 | =item limit $grp $num |
|
|
1776 | |
|
|
1777 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
1778 | the group contains less than this many requests. |
|
|
1779 | |
|
|
1780 | Setting the limit to C<0> will pause the feeding process. |
|
|
1781 | |
|
|
1782 | The default value for the limit is C<0>, but note that setting a feeder |
|
|
1783 | automatically bumps it up to C<2>. |
|
|
1784 | |
|
|
1785 | =back |
|
|
1786 | |
191 | =head2 SUPPORT FUNCTIONS |
1787 | =head2 SUPPORT FUNCTIONS |
192 | |
1788 | |
|
|
1789 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
1790 | |
193 | =over 4 |
1791 | =over 4 |
194 | |
1792 | |
195 | =item $fileno = IO::AIO::poll_fileno |
1793 | =item $fileno = IO::AIO::poll_fileno |
196 | |
1794 | |
197 | Return the I<request result pipe filehandle>. This filehandle must be |
1795 | Return the I<request result pipe file descriptor>. This filehandle must be |
198 | polled for reading by some mechanism outside this module (e.g. Event |
1796 | polled for reading by some mechanism outside this module (e.g. EV, Glib, |
199 | or select, see below). If the pipe becomes readable you have to call |
1797 | select and so on, see below or the SYNOPSIS). If the pipe becomes readable |
200 | C<poll_cb> to check the results. |
1798 | you have to call C<poll_cb> to check the results. |
201 | |
1799 | |
202 | See C<poll_cb> for an example. |
1800 | See C<poll_cb> for an example. |
203 | |
1801 | |
204 | =item IO::AIO::poll_cb |
1802 | =item IO::AIO::poll_cb |
205 | |
1803 | |
206 | Process all outstanding events on the result pipe. You have to call this |
1804 | Process some requests that have reached the result phase (i.e. they have |
207 | regularly. Returns the number of events processed. Returns immediately |
1805 | been executed but the results are not yet reported). You have to call |
208 | when no events are outstanding. |
1806 | this "regularly" to finish outstanding requests. |
209 | |
1807 | |
210 | You can use Event to multiplex, e.g.: |
1808 | Returns C<0> if all events could be processed (or there were no |
|
|
1809 | events to process), or C<-1> if it returned earlier for whatever |
|
|
1810 | reason. Returns immediately when no events are outstanding. The amount |
|
|
1811 | of events processed depends on the settings of C<IO::AIO::max_poll_req>, |
|
|
1812 | C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>. |
|
|
1813 | |
|
|
1814 | If not all requests were processed for whatever reason, the poll file |
|
|
1815 | descriptor will still be ready when C<poll_cb> returns, so normally you |
|
|
1816 | don't have to do anything special to have it called later. |
|
|
1817 | |
|
|
1818 | Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes |
|
|
1819 | ready, it can be beneficial to call this function from loops which submit |
|
|
1820 | a lot of requests, to make sure the results get processed when they become |
|
|
1821 | available and not just when the loop is finished and the event loop takes |
|
|
1822 | over again. This function returns very fast when there are no outstanding |
|
|
1823 | requests. |
|
|
1824 | |
|
|
1825 | Example: Install an Event watcher that automatically calls |
|
|
1826 | IO::AIO::poll_cb with high priority (more examples can be found in the |
|
|
1827 | SYNOPSIS section, at the top of this document): |
211 | |
1828 | |
212 | Event->io (fd => IO::AIO::poll_fileno, |
1829 | Event->io (fd => IO::AIO::poll_fileno, |
213 | poll => 'r', async => 1, |
1830 | poll => 'r', async => 1, |
214 | cb => \&IO::AIO::poll_cb); |
1831 | cb => \&IO::AIO::poll_cb); |
215 | |
1832 | |
216 | =item IO::AIO::poll_wait |
1833 | =item IO::AIO::poll_wait |
217 | |
1834 | |
218 | Wait till the result filehandle becomes ready for reading (simply does a |
1835 | Wait until either at least one request is in the result phase or no |
219 | select on the filehandle. This is useful if you want to synchronously wait |
1836 | requests are outstanding anymore. |
220 | for some requests to finish). |
1837 | |
|
|
1838 | This is useful if you want to synchronously wait for some requests to |
|
|
1839 | become ready, without actually handling them. |
221 | |
1840 | |
222 | See C<nreqs> for an example. |
1841 | See C<nreqs> for an example. |
223 | |
1842 | |
|
|
1843 | =item IO::AIO::poll |
|
|
1844 | |
|
|
1845 | Waits until some requests have been handled. |
|
|
1846 | |
|
|
1847 | Returns the number of requests processed, but is otherwise strictly |
|
|
1848 | equivalent to: |
|
|
1849 | |
|
|
1850 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1851 | |
224 | =item IO::AIO::nreqs |
1852 | =item IO::AIO::flush |
225 | |
1853 | |
226 | Returns the number of requests currently outstanding. |
1854 | Wait till all outstanding AIO requests have been handled. |
227 | |
1855 | |
228 | Example: wait till there are no outstanding requests anymore: |
1856 | Strictly equivalent to: |
229 | |
1857 | |
230 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1858 | IO::AIO::poll_wait, IO::AIO::poll_cb |
231 | while IO::AIO::nreqs; |
1859 | while IO::AIO::nreqs; |
232 | |
1860 | |
|
|
1861 | =item IO::AIO::max_poll_reqs $nreqs |
|
|
1862 | |
|
|
1863 | =item IO::AIO::max_poll_time $seconds |
|
|
1864 | |
|
|
1865 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
1866 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
1867 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
1868 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
1869 | of time C<poll_cb> is allowed to use). |
|
|
1870 | |
|
|
1871 | Setting C<max_poll_time> to a non-zero value creates an overhead of one |
|
|
1872 | syscall per request processed, which is not normally a problem unless your |
|
|
1873 | callbacks are really really fast or your OS is really really slow (I am |
|
|
1874 | not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead. |
|
|
1875 | |
|
|
1876 | Setting these is useful if you want to ensure some level of |
|
|
1877 | interactiveness when perl is not fast enough to process all requests in |
|
|
1878 | time. |
|
|
1879 | |
|
|
1880 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
|
|
1881 | |
|
|
1882 | Example: Install an Event watcher that automatically calls |
|
|
1883 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
|
|
1884 | program get the CPU sometimes even under high AIO load. |
|
|
1885 | |
|
|
1886 | # try not to spend much more than 0.1s in poll_cb |
|
|
1887 | IO::AIO::max_poll_time 0.1; |
|
|
1888 | |
|
|
1889 | # use a low priority so other tasks have priority |
|
|
1890 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1891 | poll => 'r', nice => 1, |
|
|
1892 | cb => &IO::AIO::poll_cb); |
|
|
1893 | |
|
|
1894 | =back |
|
|
1895 | |
|
|
1896 | =head3 CONTROLLING THE NUMBER OF THREADS |
|
|
1897 | |
|
|
1898 | =over |
|
|
1899 | |
233 | =item IO::AIO::min_parallel $nthreads |
1900 | =item IO::AIO::min_parallel $nthreads |
234 | |
1901 | |
235 | Set the minimum number of AIO threads to C<$nthreads>. The default is |
1902 | Set the minimum number of AIO threads to C<$nthreads>. The current |
236 | C<1>, which means a single asynchronous operation can be done at one time |
1903 | default is C<8>, which means eight asynchronous operations can execute |
237 | (the number of outstanding operations, however, is unlimited). |
1904 | concurrently at any one time (the number of outstanding requests, |
|
|
1905 | however, is unlimited). |
238 | |
1906 | |
|
|
1907 | IO::AIO starts threads only on demand, when an AIO request is queued and |
|
|
1908 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
1909 | create demand for a hundred threads, even if it turns out that everything |
|
|
1910 | is in the cache and could have been processed faster by a single thread. |
|
|
1911 | |
239 | It is recommended to keep the number of threads low, as some Linux |
1912 | It is recommended to keep the number of threads relatively low, as some |
240 | kernel versions will scale negatively with the number of threads (higher |
1913 | Linux kernel versions will scale negatively with the number of threads |
241 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
1914 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
242 | threads should be fine. |
1915 | versions, 4-32 threads should be fine. |
243 | |
1916 | |
244 | Under normal circumstances you don't need to call this function, as this |
1917 | Under most circumstances you don't need to call this function, as the |
245 | module automatically starts some threads (the exact number might change, |
1918 | module selects a default that is suitable for low to moderate load. |
246 | and is currently 4). |
|
|
247 | |
1919 | |
248 | =item IO::AIO::max_parallel $nthreads |
1920 | =item IO::AIO::max_parallel $nthreads |
249 | |
1921 | |
250 | Sets the maximum number of AIO threads to C<$nthreads>. If more than |
1922 | Sets the maximum number of AIO threads to C<$nthreads>. If more than the |
251 | the specified number of threads are currently running, kill them. This |
1923 | specified number of threads are currently running, this function kills |
252 | function blocks until the limit is reached. |
1924 | them. This function blocks until the limit is reached. |
|
|
1925 | |
|
|
1926 | While C<$nthreads> are zero, aio requests get queued but not executed |
|
|
1927 | until the number of threads has been increased again. |
253 | |
1928 | |
254 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1929 | This module automatically runs C<max_parallel 0> at program end, to ensure |
255 | that all threads are killed and that there are no outstanding requests. |
1930 | that all threads are killed and that there are no outstanding requests. |
256 | |
1931 | |
257 | Under normal circumstances you don't need to call this function. |
1932 | Under normal circumstances you don't need to call this function. |
258 | |
1933 | |
|
|
1934 | =item IO::AIO::max_idle $nthreads |
|
|
1935 | |
|
|
1936 | Limit the number of threads (default: 4) that are allowed to idle |
|
|
1937 | (i.e., threads that did not get a request to process within the idle |
|
|
1938 | timeout (default: 10 seconds). That means if a thread becomes idle while |
|
|
1939 | C<$nthreads> other threads are also idle, it will free its resources and |
|
|
1940 | exit. |
|
|
1941 | |
|
|
1942 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1943 | to allow for extremely high load situations, but want to free resources |
|
|
1944 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1945 | |
|
|
1946 | The default is probably ok in most situations, especially if thread |
|
|
1947 | creation is fast. If thread creation is very slow on your system you might |
|
|
1948 | want to use larger values. |
|
|
1949 | |
|
|
1950 | =item IO::AIO::idle_timeout $seconds |
|
|
1951 | |
|
|
1952 | Sets the minimum idle timeout (default 10) after which worker threads are |
|
|
1953 | allowed to exit. SEe C<IO::AIO::max_idle>. |
|
|
1954 | |
259 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
1955 | =item IO::AIO::max_outstanding $maxreqs |
260 | |
1956 | |
261 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1957 | Sets the maximum number of outstanding requests to C<$nreqs>. If |
262 | try to queue up more than this number of requests, the caller will block until |
1958 | you do queue up more than this number of requests, the next call to |
263 | some requests have been handled. |
1959 | C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as |
|
|
1960 | C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no |
|
|
1961 | longer exceeded. |
264 | |
1962 | |
265 | The default is very large, so normally there is no practical limit. If you |
1963 | In other words, this setting does not enforce a queue limit, but can be |
266 | queue up many requests in a loop it it often improves speed if you set |
1964 | used to make poll functions block if the limit is exceeded. |
267 | this to a relatively low number, such as C<100>. |
|
|
268 | |
1965 | |
269 | Under normal circumstances you don't need to call this function. |
1966 | This is a very bad function to use in interactive programs because it |
|
|
1967 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1968 | use an C<aio_group> together with a feed callback. |
|
|
1969 | |
|
|
1970 | Its main use is in scripts without an event loop - when you want to stat |
|
|
1971 | a lot of files, you can write something like this: |
|
|
1972 | |
|
|
1973 | IO::AIO::max_outstanding 32; |
|
|
1974 | |
|
|
1975 | for my $path (...) { |
|
|
1976 | aio_stat $path , ...; |
|
|
1977 | IO::AIO::poll_cb; |
|
|
1978 | } |
|
|
1979 | |
|
|
1980 | IO::AIO::flush; |
|
|
1981 | |
|
|
1982 | The call to C<poll_cb> inside the loop will normally return instantly, but |
|
|
1983 | as soon as more thna C<32> reqeusts are in-flight, it will block until |
|
|
1984 | some requests have been handled. This keeps the loop from pushing a large |
|
|
1985 | number of C<aio_stat> requests onto the queue. |
|
|
1986 | |
|
|
1987 | The default value for C<max_outstanding> is very large, so there is no |
|
|
1988 | practical limit on the number of outstanding requests. |
270 | |
1989 | |
271 | =back |
1990 | =back |
272 | |
1991 | |
|
|
1992 | =head3 STATISTICAL INFORMATION |
|
|
1993 | |
|
|
1994 | =over |
|
|
1995 | |
|
|
1996 | =item IO::AIO::nreqs |
|
|
1997 | |
|
|
1998 | Returns the number of requests currently in the ready, execute or pending |
|
|
1999 | states (i.e. for which their callback has not been invoked yet). |
|
|
2000 | |
|
|
2001 | Example: wait till there are no outstanding requests anymore: |
|
|
2002 | |
|
|
2003 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
2004 | while IO::AIO::nreqs; |
|
|
2005 | |
|
|
2006 | =item IO::AIO::nready |
|
|
2007 | |
|
|
2008 | Returns the number of requests currently in the ready state (not yet |
|
|
2009 | executed). |
|
|
2010 | |
|
|
2011 | =item IO::AIO::npending |
|
|
2012 | |
|
|
2013 | Returns the number of requests currently in the pending state (executed, |
|
|
2014 | but not yet processed by poll_cb). |
|
|
2015 | |
|
|
2016 | =back |
|
|
2017 | |
|
|
2018 | =head3 SUBSECOND STAT TIME ACCESS |
|
|
2019 | |
|
|
2020 | Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can |
|
|
2021 | generally find access/modification and change times with subsecond time |
|
|
2022 | accuracy of the system supports it, but perl's built-in functions only |
|
|
2023 | return the integer part. |
|
|
2024 | |
|
|
2025 | The following functions return the timestamps of the most recent |
|
|
2026 | stat with subsecond precision on most systems and work both after |
|
|
2027 | C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return |
|
|
2028 | value is only meaningful after a successful C<stat>/C<lstat> call, or |
|
|
2029 | during/after a successful C<aio_stat>/C<aio_lstat> callback. |
|
|
2030 | |
|
|
2031 | This is similar to the L<Time::HiRes> C<stat> functions, but can return |
|
|
2032 | full resolution without rounding and work with standard perl C<stat>, |
|
|
2033 | alleviating the need to call the special C<Time::HiRes> functions, which |
|
|
2034 | do not act like their perl counterparts. |
|
|
2035 | |
|
|
2036 | On operating systems or file systems where subsecond time resolution is |
|
|
2037 | not supported or could not be detected, a fractional part of C<0> is |
|
|
2038 | returned, so it is always safe to call these functions. |
|
|
2039 | |
|
|
2040 | =over 4 |
|
|
2041 | |
|
|
2042 | =item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime |
|
|
2043 | |
|
|
2044 | Return the access, modication or change time, respectively, including |
|
|
2045 | fractional part. Due to the limited precision of floating point, the |
|
|
2046 | accuracy on most platforms is only a bit better than milliseconds for |
|
|
2047 | times around now - see the I<nsec> function family, below, for full |
|
|
2048 | accuracy. |
|
|
2049 | |
|
|
2050 | =item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtime |
|
|
2051 | |
|
|
2052 | Returns access, modification and change time all in one go, and maybe more |
|
|
2053 | times in the future version. |
|
|
2054 | |
|
|
2055 | =item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec |
|
|
2056 | |
|
|
2057 | Return the fractional access, modifcation or change time, in nanoseconds, |
|
|
2058 | as an integer in the range C<0> to C<999999999>. |
|
|
2059 | |
|
|
2060 | =item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtimensec |
|
|
2061 | |
|
|
2062 | Like the functions above, but returns all three times in one go (and maybe |
|
|
2063 | more in future versions). |
|
|
2064 | |
|
|
2065 | =back |
|
|
2066 | |
|
|
2067 | Example: print the high resolution modification time of F</etc>, using |
|
|
2068 | C<stat>, and C<IO::AIO::aio_stat>. |
|
|
2069 | |
|
|
2070 | if (stat "/etc") { |
|
|
2071 | printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime; |
|
|
2072 | } |
|
|
2073 | |
|
|
2074 | IO::AIO::aio_stat "/etc", sub { |
|
|
2075 | $_[0] |
|
|
2076 | and return; |
|
|
2077 | |
|
|
2078 | printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec; |
|
|
2079 | }; |
|
|
2080 | |
|
|
2081 | IO::AIO::flush; |
|
|
2082 | |
|
|
2083 | Output of the awbove on my system, showing reduced and full accuracy: |
|
|
2084 | |
|
|
2085 | stat(/etc) mtime: 1534043702.020808 |
|
|
2086 | aio_stat(/etc) mtime: 1534043702.020807792 |
|
|
2087 | |
|
|
2088 | =head3 MISCELLANEOUS FUNCTIONS |
|
|
2089 | |
|
|
2090 | IO::AIO implements some functions that are useful when you want to use |
|
|
2091 | some "Advanced I/O" function not available to in Perl, without going the |
|
|
2092 | "Asynchronous I/O" route. Many of these have an asynchronous C<aio_*> |
|
|
2093 | counterpart. |
|
|
2094 | |
|
|
2095 | =over 4 |
|
|
2096 | |
|
|
2097 | =item $numfd = IO::AIO::get_fdlimit |
|
|
2098 | |
|
|
2099 | This function is I<EXPERIMENTAL> and subject to change. |
|
|
2100 | |
|
|
2101 | Tries to find the current file descriptor limit and returns it, or |
|
|
2102 | C<undef> and sets C<$!> in case of an error. The limit is one larger than |
|
|
2103 | the highest valid file descriptor number. |
|
|
2104 | |
|
|
2105 | =item IO::AIO::min_fdlimit [$numfd] |
|
|
2106 | |
|
|
2107 | This function is I<EXPERIMENTAL> and subject to change. |
|
|
2108 | |
|
|
2109 | Try to increase the current file descriptor limit(s) to at least C<$numfd> |
|
|
2110 | by changing the soft or hard file descriptor resource limit. If C<$numfd> |
|
|
2111 | is missing, it will try to set a very high limit, although this is not |
|
|
2112 | recommended when you know the actual minimum that you require. |
|
|
2113 | |
|
|
2114 | If the limit cannot be raised enough, the function makes a best-effort |
|
|
2115 | attempt to increase the limit as much as possible, using various |
|
|
2116 | tricks, while still failing. You can query the resulting limit using |
|
|
2117 | C<IO::AIO::get_fdlimit>. |
|
|
2118 | |
|
|
2119 | If an error occurs, returns C<undef> and sets C<$!>, otherwise returns |
|
|
2120 | true. |
|
|
2121 | |
|
|
2122 | =item IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
2123 | |
|
|
2124 | Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, |
|
|
2125 | but is blocking (this makes most sense if you know the input data is |
|
|
2126 | likely cached already and the output filehandle is set to non-blocking |
|
|
2127 | operations). |
|
|
2128 | |
|
|
2129 | Returns the number of bytes copied, or C<-1> on error. |
|
|
2130 | |
|
|
2131 | =item IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
2132 | |
|
|
2133 | Simply calls the C<posix_fadvise> function (see its |
|
|
2134 | manpage for details). The following advice constants are |
|
|
2135 | available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, |
|
|
2136 | C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, |
|
|
2137 | C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. |
|
|
2138 | |
|
|
2139 | On systems that do not implement C<posix_fadvise>, this function returns |
|
|
2140 | ENOSYS, otherwise the return value of C<posix_fadvise>. |
|
|
2141 | |
|
|
2142 | =item IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
2143 | |
|
|
2144 | Simply calls the C<posix_madvise> function (see its |
|
|
2145 | manpage for details). The following advice constants are |
|
|
2146 | available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, |
|
|
2147 | C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, |
|
|
2148 | C<IO::AIO::MADV_DONTNEED>. |
|
|
2149 | |
|
|
2150 | If C<$offset> is negative, counts from the end. If C<$length> is negative, |
|
|
2151 | the remaining length of the C<$scalar> is used. If possible, C<$length> |
|
|
2152 | will be reduced to fit into the C<$scalar>. |
|
|
2153 | |
|
|
2154 | On systems that do not implement C<posix_madvise>, this function returns |
|
|
2155 | ENOSYS, otherwise the return value of C<posix_madvise>. |
|
|
2156 | |
|
|
2157 | =item IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
2158 | |
|
|
2159 | Simply calls the C<mprotect> function on the preferably AIO::mmap'ed |
|
|
2160 | $scalar (see its manpage for details). The following protect |
|
|
2161 | constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, |
|
|
2162 | C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. |
|
|
2163 | |
|
|
2164 | If C<$offset> is negative, counts from the end. If C<$length> is negative, |
|
|
2165 | the remaining length of the C<$scalar> is used. If possible, C<$length> |
|
|
2166 | will be reduced to fit into the C<$scalar>. |
|
|
2167 | |
|
|
2168 | On systems that do not implement C<mprotect>, this function returns |
|
|
2169 | ENOSYS, otherwise the return value of C<mprotect>. |
|
|
2170 | |
|
|
2171 | =item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
2172 | |
|
|
2173 | Memory-maps a file (or anonymous memory range) and attaches it to the |
|
|
2174 | given C<$scalar>, which will act like a string scalar. Returns true on |
|
|
2175 | success, and false otherwise. |
|
|
2176 | |
|
|
2177 | The scalar must exist, but its contents do not matter - this means you |
|
|
2178 | cannot use a nonexistant array or hash element. When in doubt, C<undef> |
|
|
2179 | the scalar first. |
|
|
2180 | |
|
|
2181 | The only operations allowed on the mmapped scalar are C<substr>/C<vec>, |
|
|
2182 | which don't change the string length, and most read-only operations such |
|
|
2183 | as copying it or searching it with regexes and so on. |
|
|
2184 | |
|
|
2185 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
2186 | |
|
|
2187 | The memory map associated with the C<$scalar> is automatically removed |
|
|
2188 | when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap> |
|
|
2189 | or C<IO::AIO::munmap> functions are called on it. |
|
|
2190 | |
|
|
2191 | This calls the C<mmap>(2) function internally. See your system's manual |
|
|
2192 | page for details on the C<$length>, C<$prot> and C<$flags> parameters. |
|
|
2193 | |
|
|
2194 | The C<$length> must be larger than zero and smaller than the actual |
|
|
2195 | filesize. |
|
|
2196 | |
|
|
2197 | C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, |
|
|
2198 | C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, |
|
|
2199 | |
|
|
2200 | C<$flags> can be a combination of |
|
|
2201 | C<IO::AIO::MAP_SHARED> or |
|
|
2202 | C<IO::AIO::MAP_PRIVATE>, |
|
|
2203 | or a number of system-specific flags (when not available, the are C<0>): |
|
|
2204 | C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant), |
|
|
2205 | C<IO::AIO::MAP_LOCKED>, |
|
|
2206 | C<IO::AIO::MAP_NORESERVE>, |
|
|
2207 | C<IO::AIO::MAP_POPULATE>, |
|
|
2208 | C<IO::AIO::MAP_NONBLOCK>, |
|
|
2209 | C<IO::AIO::MAP_FIXED>, |
|
|
2210 | C<IO::AIO::MAP_GROWSDOWN>, |
|
|
2211 | C<IO::AIO::MAP_32BIT>, |
|
|
2212 | C<IO::AIO::MAP_HUGETLB> or |
|
|
2213 | C<IO::AIO::MAP_STACK>. |
|
|
2214 | |
|
|
2215 | If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. |
|
|
2216 | |
|
|
2217 | C<$offset> is the offset from the start of the file - it generally must be |
|
|
2218 | a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. |
|
|
2219 | |
|
|
2220 | Example: |
|
|
2221 | |
|
|
2222 | use Digest::MD5; |
|
|
2223 | use IO::AIO; |
|
|
2224 | |
|
|
2225 | open my $fh, "<verybigfile" |
|
|
2226 | or die "$!"; |
|
|
2227 | |
|
|
2228 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
2229 | or die "verybigfile: $!"; |
|
|
2230 | |
|
|
2231 | my $fast_md5 = md5 $data; |
|
|
2232 | |
|
|
2233 | =item IO::AIO::munmap $scalar |
|
|
2234 | |
|
|
2235 | Removes a previous mmap and undefines the C<$scalar>. |
|
|
2236 | |
|
|
2237 | =item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0] |
|
|
2238 | |
|
|
2239 | Calls the Linux-specific mremap(2) system call. The C<$scalar> must have |
|
|
2240 | been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be |
|
|
2241 | C<0> or C<IO::AIO::MREMAP_MAYMOVE>. |
|
|
2242 | |
|
|
2243 | Returns true if successful, and false otherwise. If the underlying mmapped |
|
|
2244 | region has changed address, then the true value has the numerical value |
|
|
2245 | C<1>, otherwise it has the numerical value C<0>: |
|
|
2246 | |
|
|
2247 | my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE |
|
|
2248 | or die "mremap: $!"; |
|
|
2249 | |
|
|
2250 | if ($success*1) { |
|
|
2251 | warn "scalar has chanegd address in memory\n"; |
|
|
2252 | } |
|
|
2253 | |
|
|
2254 | C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently |
|
|
2255 | implemented, but not supported and might go away in a future version. |
|
|
2256 | |
|
|
2257 | On systems where this call is not supported or is not emulated, this call |
|
|
2258 | returns falls and sets C<$!> to C<ENOSYS>. |
|
|
2259 | |
|
|
2260 | =item IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
2261 | |
|
|
2262 | Calls the C<munlock> function, undoing the effects of a previous |
|
|
2263 | C<aio_mlock> call (see its description for details). |
|
|
2264 | |
|
|
2265 | =item IO::AIO::munlockall |
|
|
2266 | |
|
|
2267 | Calls the C<munlockall> function. |
|
|
2268 | |
|
|
2269 | On systems that do not implement C<munlockall>, this function returns |
|
|
2270 | ENOSYS, otherwise the return value of C<munlockall>. |
|
|
2271 | |
|
|
2272 | =item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags |
|
|
2273 | |
|
|
2274 | Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or |
|
|
2275 | C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they |
|
|
2276 | should be the file offset. |
|
|
2277 | |
|
|
2278 | C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might |
|
|
2279 | silently corrupt the data in this case. |
|
|
2280 | |
|
|
2281 | The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>, |
|
|
2282 | C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and |
|
|
2283 | C<IO::AIO::SPLICE_F_GIFT>. |
|
|
2284 | |
|
|
2285 | See the C<splice(2)> manpage for details. |
|
|
2286 | |
|
|
2287 | =item IO::AIO::tee $r_fh, $w_fh, $length, $flags |
|
|
2288 | |
|
|
2289 | Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the |
|
|
2290 | description for C<IO::AIO::splice> above for details. |
|
|
2291 | |
|
|
2292 | =item $actual_size = IO::AIO::pipesize $r_fh[, $new_size] |
|
|
2293 | |
|
|
2294 | Attempts to query or change the pipe buffer size. Obviously works only |
|
|
2295 | on pipes, and currently works only on GNU/Linux systems, and fails with |
|
|
2296 | C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer |
|
|
2297 | size on other systems, drop me a note. |
|
|
2298 | |
|
|
2299 | =item ($rfh, $wfh) = IO::AIO::pipe2 [$flags] |
|
|
2300 | |
|
|
2301 | This is a direct interface to the Linux L<pipe2(2)> system call. If |
|
|
2302 | C<$flags> is missing or C<0>, then this should be the same as a call to |
|
|
2303 | perl's built-in C<pipe> function and create a new pipe, and works on |
|
|
2304 | systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe |
|
|
2305 | (..., 4096, O_BINARY)>. |
|
|
2306 | |
|
|
2307 | If C<$flags> is non-zero, it tries to invoke the pipe2 system call with |
|
|
2308 | the given flags (Linux 2.6.27, glibc 2.9). |
|
|
2309 | |
|
|
2310 | On success, the read and write file handles are returned. |
|
|
2311 | |
|
|
2312 | On error, nothing will be returned. If the pipe2 syscall is missing and |
|
|
2313 | C<$flags> is non-zero, fails with C<ENOSYS>. |
|
|
2314 | |
|
|
2315 | Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the |
|
|
2316 | time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and |
|
|
2317 | C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported. |
|
|
2318 | |
|
|
2319 | Example: create a pipe race-free w.r.t. threads and fork: |
|
|
2320 | |
|
|
2321 | my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC |
|
|
2322 | or die "pipe2: $!\n"; |
|
|
2323 | |
|
|
2324 | =item $fh = IO::AIO::eventfd [$initval, [$flags]] |
|
|
2325 | |
|
|
2326 | This is a direct interface to the Linux L<eventfd(2)> system call. The |
|
|
2327 | (unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both. |
|
|
2328 | |
|
|
2329 | On success, the new eventfd filehandle is returned, otherwise returns |
|
|
2330 | C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>. |
|
|
2331 | |
|
|
2332 | Please refer to L<eventfd(2)> for more info on this call. |
|
|
2333 | |
|
|
2334 | The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>, |
|
|
2335 | C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30). |
|
|
2336 | |
|
|
2337 | Example: create a new eventfd filehandle: |
|
|
2338 | |
|
|
2339 | $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC |
|
|
2340 | or die "eventfd: $!\n"; |
|
|
2341 | |
|
|
2342 | =item $fh = IO::AIO::timerfd_create $clockid[, $flags] |
|
|
2343 | |
|
|
2344 | This is a direct interface to the Linux L<timerfd_create(2)> system call. The |
|
|
2345 | (unhelpful) default for C<$flags> is C<0>. |
|
|
2346 | |
|
|
2347 | On success, the new timerfd filehandle is returned, otherwise returns |
|
|
2348 | C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>. |
|
|
2349 | |
|
|
2350 | Please refer to L<timerfd_create(2)> for more info on this call. |
|
|
2351 | |
|
|
2352 | The following C<$clockid> values are |
|
|
2353 | available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC> |
|
|
2354 | C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15) |
|
|
2355 | C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and |
|
|
2356 | C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11). |
|
|
2357 | |
|
|
2358 | The following C<$flags> values are available (Linux |
|
|
2359 | 2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>. |
|
|
2360 | |
|
|
2361 | Example: create a new timerfd and set it to one-second repeated alarms, |
|
|
2362 | then wait for two alarms: |
|
|
2363 | |
|
|
2364 | my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC |
|
|
2365 | or die "timerfd_create: $!\n"; |
|
|
2366 | |
|
|
2367 | defined IO::AIO::timerfd_settime $fh, 0, 1, 1 |
|
|
2368 | or die "timerfd_settime: $!\n"; |
|
|
2369 | |
|
|
2370 | for (1..2) { |
|
|
2371 | 8 == sysread $fh, my $buf, 8 |
|
|
2372 | or die "timerfd read failure\n"; |
|
|
2373 | |
|
|
2374 | printf "number of expirations (likely 1): %d\n", |
|
|
2375 | unpack "Q", $buf; |
|
|
2376 | } |
|
|
2377 | |
|
|
2378 | =item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value |
|
|
2379 | |
|
|
2380 | This is a direct interface to the Linux L<timerfd_settime(2)> system |
|
|
2381 | call. Please refer to its manpage for more info on this call. |
|
|
2382 | |
|
|
2383 | The new itimerspec is specified using two (possibly fractional) second |
|
|
2384 | values, C<$new_interval> and C<$new_value>). |
|
|
2385 | |
|
|
2386 | On success, the current interval and value are returned (as per |
|
|
2387 | C<timerfd_gettime>). On failure, the empty list is returned. |
|
|
2388 | |
|
|
2389 | The following C<$flags> values are |
|
|
2390 | available: C<IO::AIO::TFD_TIMER_ABSTIME> and |
|
|
2391 | C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>. |
|
|
2392 | |
|
|
2393 | See C<IO::AIO::timerfd_create> for a full example. |
|
|
2394 | |
|
|
2395 | =item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh |
|
|
2396 | |
|
|
2397 | This is a direct interface to the Linux L<timerfd_gettime(2)> system |
|
|
2398 | call. Please refer to its manpage for more info on this call. |
|
|
2399 | |
|
|
2400 | On success, returns the current values of interval and value for the given |
|
|
2401 | timerfd (as potentially fractional second values). On failure, the empty |
|
|
2402 | list is returned. |
|
|
2403 | |
|
|
2404 | =back |
|
|
2405 | |
273 | =cut |
2406 | =cut |
274 | |
2407 | |
275 | # support function to convert a fd into a perl filehandle |
|
|
276 | sub _fd2fh { |
|
|
277 | return undef if $_[0] < 0; |
|
|
278 | |
|
|
279 | # try to be perl5.6-compatible |
|
|
280 | local *AIO_FH; |
|
|
281 | open AIO_FH, "+<&=$_[0]" |
|
|
282 | or return undef; |
|
|
283 | |
|
|
284 | *AIO_FH |
|
|
285 | } |
|
|
286 | |
|
|
287 | min_parallel 4; |
2408 | min_parallel 8; |
288 | |
2409 | |
289 | END { |
2410 | END { flush } |
290 | max_parallel 0; |
|
|
291 | } |
|
|
292 | |
2411 | |
293 | 1; |
2412 | 1; |
294 | |
2413 | |
|
|
2414 | =head1 EVENT LOOP INTEGRATION |
|
|
2415 | |
|
|
2416 | It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO |
|
|
2417 | automatically into many event loops: |
|
|
2418 | |
|
|
2419 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
2420 | use AnyEvent::AIO; |
|
|
2421 | |
|
|
2422 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
2423 | some examples of how to do this: |
|
|
2424 | |
|
|
2425 | # EV integration |
|
|
2426 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
2427 | |
|
|
2428 | # Event integration |
|
|
2429 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
2430 | poll => 'r', |
|
|
2431 | cb => \&IO::AIO::poll_cb); |
|
|
2432 | |
|
|
2433 | # Glib/Gtk2 integration |
|
|
2434 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
2435 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
2436 | |
|
|
2437 | # Tk integration |
|
|
2438 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
2439 | readable => \&IO::AIO::poll_cb); |
|
|
2440 | |
|
|
2441 | # Danga::Socket integration |
|
|
2442 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
2443 | \&IO::AIO::poll_cb); |
|
|
2444 | |
|
|
2445 | =head2 FORK BEHAVIOUR |
|
|
2446 | |
|
|
2447 | Usage of pthreads in a program changes the semantics of fork |
|
|
2448 | considerably. Specifically, only async-safe functions can be called after |
|
|
2449 | fork. Perl doesn't know about this, so in general, you cannot call fork |
|
|
2450 | with defined behaviour in perl if pthreads are involved. IO::AIO uses |
|
|
2451 | pthreads, so this applies, but many other extensions and (for inexplicable |
|
|
2452 | reasons) perl itself often is linked against pthreads, so this limitation |
|
|
2453 | applies to quite a lot of perls. |
|
|
2454 | |
|
|
2455 | This module no longer tries to fight your OS, or POSIX. That means IO::AIO |
|
|
2456 | only works in the process that loaded it. Forking is fully supported, but |
|
|
2457 | using IO::AIO in the child is not. |
|
|
2458 | |
|
|
2459 | You might get around by not I<using> IO::AIO before (or after) |
|
|
2460 | forking. You could also try to call the L<IO::AIO::reinit> function in the |
|
|
2461 | child: |
|
|
2462 | |
|
|
2463 | =over 4 |
|
|
2464 | |
|
|
2465 | =item IO::AIO::reinit |
|
|
2466 | |
|
|
2467 | Abandons all current requests and I/O threads and simply reinitialises all |
|
|
2468 | data structures. This is not an operation supported by any standards, but |
|
|
2469 | happens to work on GNU/Linux and some newer BSD systems. |
|
|
2470 | |
|
|
2471 | The only reasonable use for this function is to call it after forking, if |
|
|
2472 | C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in |
|
|
2473 | the process will result in undefined behaviour. Calling it at any time |
|
|
2474 | will also result in any undefined (by POSIX) behaviour. |
|
|
2475 | |
|
|
2476 | =back |
|
|
2477 | |
|
|
2478 | =head2 LINUX-SPECIFIC CALLS |
|
|
2479 | |
|
|
2480 | When a call is documented as "linux-specific" then this means it |
|
|
2481 | originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the |
|
|
2482 | availability and compatibility of such calls regardless of the platform |
|
|
2483 | it is compiled on, so platforms such as FreeBSD which often implement |
|
|
2484 | these calls will work. When in doubt, call them and see if they fail wth |
|
|
2485 | C<ENOSYS>. |
|
|
2486 | |
|
|
2487 | =head2 MEMORY USAGE |
|
|
2488 | |
|
|
2489 | Per-request usage: |
|
|
2490 | |
|
|
2491 | Each aio request uses - depending on your architecture - around 100-200 |
|
|
2492 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
|
|
2493 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
|
|
2494 | scalars and other data passed into aio requests will also be locked and |
|
|
2495 | will consume memory till the request has entered the done state. |
|
|
2496 | |
|
|
2497 | This is not awfully much, so queuing lots of requests is not usually a |
|
|
2498 | problem. |
|
|
2499 | |
|
|
2500 | Per-thread usage: |
|
|
2501 | |
|
|
2502 | In the execution phase, some aio requests require more memory for |
|
|
2503 | temporary buffers, and each thread requires a stack and other data |
|
|
2504 | structures (usually around 16k-128k, depending on the OS). |
|
|
2505 | |
|
|
2506 | =head1 KNOWN BUGS |
|
|
2507 | |
|
|
2508 | Known bugs will be fixed in the next release :) |
|
|
2509 | |
|
|
2510 | =head1 KNOWN ISSUES |
|
|
2511 | |
|
|
2512 | Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap> |
|
|
2513 | or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as |
|
|
2514 | non-created hash slots or other scalars I didn't think of. It's best to |
|
|
2515 | avoid such and either use scalar variables or making sure that the scalar |
|
|
2516 | exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied). |
|
|
2517 | |
|
|
2518 | I am not sure anything can be done about this, so this is considered a |
|
|
2519 | known issue, rather than a bug. |
|
|
2520 | |
295 | =head1 SEE ALSO |
2521 | =head1 SEE ALSO |
296 | |
2522 | |
297 | L<Coro>, L<Linux::AIO>. |
2523 | L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a |
|
|
2524 | more natural syntax. |
298 | |
2525 | |
299 | =head1 AUTHOR |
2526 | =head1 AUTHOR |
300 | |
2527 | |
301 | Marc Lehmann <schmorp@schmorp.de> |
2528 | Marc Lehmann <schmorp@schmorp.de> |
302 | http://home.schmorp.de/ |
2529 | http://home.schmorp.de/ |