… | |
… | |
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 | in => sub { IO::AIO::poll_cb; 1 }; |
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 | |
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33 | # Danga::Socket |
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34 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
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35 | \&IO::AIO::poll_cb); |
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36 | |
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37 | |
30 | |
38 | =head1 DESCRIPTION |
31 | =head1 DESCRIPTION |
39 | |
32 | |
40 | This module implements asynchronous I/O using whatever means your |
33 | This module implements asynchronous I/O using whatever means your |
41 | 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>). |
42 | |
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 | |
43 | 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 |
44 | 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 |
45 | 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 |
46 | 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 |
47 | aio functions available on many operating systems. However, they are often |
57 | functions available on many operating systems. However, they are often |
48 | 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 |
49 | 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 |
50 | 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. |
51 | |
62 | |
52 | Although the module will work with in the presence of other threads, it is |
63 | Although the module will work in the presence of other (Perl-) threads, |
53 | currently not reentrant, so use appropriate locking yourself, always call |
64 | it is currently not reentrant in any way, so use appropriate locking |
54 | C<poll_cb> from within the same thread, or never call C<poll_cb> (or other |
65 | yourself, always call C<poll_cb> from within the same thread, or never |
55 | C<aio_> functions) recursively. |
66 | call C<poll_cb> (or other C<aio_> functions) recursively. |
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67 | |
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68 | =head2 EXAMPLE |
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69 | |
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70 | This is a simple example that uses the EV module and loads |
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71 | F</etc/passwd> asynchronously: |
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72 | |
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73 | use Fcntl; |
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74 | use EV; |
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75 | use IO::AIO; |
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76 | |
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77 | # register the IO::AIO callback with EV |
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78 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
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79 | |
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80 | # queue the request to open /etc/passwd |
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81 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
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82 | my $fh = shift |
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83 | or die "error while opening: $!"; |
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84 | |
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85 | # stat'ing filehandles is generally non-blocking |
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86 | my $size = -s $fh; |
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87 | |
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88 | # queue a request to read the file |
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89 | my $contents; |
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90 | aio_read $fh, 0, $size, $contents, 0, sub { |
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91 | $_[0] == $size |
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92 | or die "short read: $!"; |
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93 | |
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94 | close $fh; |
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95 | |
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96 | # file contents now in $contents |
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97 | print $contents; |
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98 | |
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99 | # exit event loop and program |
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100 | EV::unloop; |
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101 | }; |
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102 | }; |
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103 | |
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104 | # possibly queue up other requests, or open GUI windows, |
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105 | # check for sockets etc. etc. |
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106 | |
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107 | # process events as long as there are some: |
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108 | EV::loop; |
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109 | |
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110 | =head1 REQUEST ANATOMY AND LIFETIME |
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111 | |
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112 | Every C<aio_*> function creates a request. which is a C data structure not |
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113 | directly visible to Perl. |
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114 | |
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115 | If called in non-void context, every request function returns a Perl |
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116 | object representing the request. In void context, nothing is returned, |
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117 | which saves a bit of memory. |
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118 | |
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119 | The perl object is a fairly standard ref-to-hash object. The hash contents |
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120 | are not used by IO::AIO so you are free to store anything you like in it. |
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121 | |
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122 | During their existance, aio requests travel through the following states, |
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123 | in order: |
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124 | |
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125 | =over 4 |
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126 | |
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127 | =item ready |
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128 | |
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129 | Immediately after a request is created it is put into the ready state, |
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130 | waiting for a thread to execute it. |
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131 | |
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132 | =item execute |
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133 | |
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134 | A thread has accepted the request for processing and is currently |
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135 | executing it (e.g. blocking in read). |
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136 | |
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137 | =item pending |
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138 | |
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139 | The request has been executed and is waiting for result processing. |
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140 | |
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141 | While request submission and execution is fully asynchronous, result |
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142 | processing is not and relies on the perl interpreter calling C<poll_cb> |
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143 | (or another function with the same effect). |
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144 | |
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145 | =item result |
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146 | |
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147 | The request results are processed synchronously by C<poll_cb>. |
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148 | |
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149 | The C<poll_cb> function will process all outstanding aio requests by |
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150 | calling their callbacks, freeing memory associated with them and managing |
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151 | any groups they are contained in. |
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152 | |
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153 | =item done |
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154 | |
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155 | Request has reached the end of its lifetime and holds no resources anymore |
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156 | (except possibly for the Perl object, but its connection to the actual |
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157 | aio request is severed and calling its methods will either do nothing or |
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158 | result in a runtime error). |
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159 | |
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160 | =back |
56 | |
161 | |
57 | =cut |
162 | =cut |
58 | |
163 | |
59 | package IO::AIO; |
164 | package IO::AIO; |
60 | |
165 | |
61 | no warnings; |
166 | use Carp (); |
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167 | |
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168 | use common::sense; |
62 | |
169 | |
63 | use base 'Exporter'; |
170 | use base 'Exporter'; |
64 | |
171 | |
65 | use Fcntl (); |
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66 | |
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67 | BEGIN { |
172 | BEGIN { |
68 | $VERSION = 1.6; |
173 | our $VERSION = '4.13'; |
69 | |
174 | |
70 | @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close stat |
175 | our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close |
71 | aio_aio_lstat aio_unlink aio_rmdir aio_readdir aio_symlink |
176 | aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx |
72 | aio_fsync aio_fdatasync aio_readahead); |
177 | aio_scandir aio_symlink aio_readlink aio_realpath aio_sync |
73 | @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel |
178 | aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate |
74 | max_outstanding nreqs); |
179 | aio_pathsync aio_readahead |
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180 | aio_rename aio_link aio_move aio_copy aio_group |
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181 | aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown |
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182 | aio_chmod aio_utime aio_truncate |
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183 | aio_msync aio_mtouch aio_mlock aio_mlockall |
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184 | aio_statvfs |
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185 | aio_wd); |
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186 | |
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187 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
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188 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
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189 | min_parallel max_parallel max_idle idle_timeout |
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190 | nreqs nready npending nthreads |
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191 | max_poll_time max_poll_reqs |
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192 | sendfile fadvise madvise |
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193 | mmap munmap munlock munlockall); |
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194 | |
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195 | push @AIO_REQ, qw(aio_busy); # not exported |
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196 | |
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197 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
75 | |
198 | |
76 | require XSLoader; |
199 | require XSLoader; |
77 | XSLoader::load IO::AIO, $VERSION; |
200 | XSLoader::load ("IO::AIO", $VERSION); |
78 | } |
201 | } |
79 | |
202 | |
80 | =head1 FUNCTIONS |
203 | =head1 FUNCTIONS |
81 | |
204 | |
82 | =head2 AIO FUNCTIONS |
205 | =head2 QUICK OVERVIEW |
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206 | |
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207 | This section simply lists the prototypes of the most important functions |
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208 | for quick reference. See the following sections for function-by-function |
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209 | documentation. |
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210 | |
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211 | aio_wd $pathname, $callback->($wd) |
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212 | aio_open $pathname, $flags, $mode, $callback->($fh) |
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213 | aio_close $fh, $callback->($status) |
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214 | aio_seek $fh,$offset,$whence, $callback->($offs) |
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215 | aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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216 | aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
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217 | aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
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218 | aio_readahead $fh,$offset,$length, $callback->($retval) |
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219 | aio_stat $fh_or_path, $callback->($status) |
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220 | aio_lstat $fh, $callback->($status) |
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221 | aio_statvfs $fh_or_path, $callback->($statvfs) |
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222 | aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
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223 | aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
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224 | aio_chmod $fh_or_path, $mode, $callback->($status) |
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225 | aio_truncate $fh_or_path, $offset, $callback->($status) |
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226 | aio_unlink $pathname, $callback->($status) |
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227 | aio_mknod $pathname, $mode, $dev, $callback->($status) |
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228 | aio_link $srcpath, $dstpath, $callback->($status) |
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229 | aio_symlink $srcpath, $dstpath, $callback->($status) |
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230 | aio_readlink $pathname, $callback->($link) |
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231 | aio_realpath $pathname, $callback->($link) |
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232 | aio_rename $srcpath, $dstpath, $callback->($status) |
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233 | aio_mkdir $pathname, $mode, $callback->($status) |
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234 | aio_rmdir $pathname, $callback->($status) |
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235 | aio_readdir $pathname, $callback->($entries) |
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236 | aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
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237 | IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST |
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238 | IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN |
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239 | aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
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240 | aio_load $pathname, $data, $callback->($status) |
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241 | aio_copy $srcpath, $dstpath, $callback->($status) |
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242 | aio_move $srcpath, $dstpath, $callback->($status) |
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243 | aio_rmtree $pathname, $callback->($status) |
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244 | aio_sync $callback->($status) |
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245 | aio_syncfs $fh, $callback->($status) |
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246 | aio_fsync $fh, $callback->($status) |
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247 | aio_fdatasync $fh, $callback->($status) |
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248 | aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
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249 | aio_pathsync $pathname, $callback->($status) |
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250 | aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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251 | aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
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252 | aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
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253 | aio_mlockall $flags, $callback->($status) |
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254 | aio_group $callback->(...) |
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255 | aio_nop $callback->() |
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256 | |
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257 | $prev_pri = aioreq_pri [$pri] |
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258 | aioreq_nice $pri_adjust |
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259 | |
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260 | IO::AIO::poll_wait |
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261 | IO::AIO::poll_cb |
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262 | IO::AIO::poll |
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263 | IO::AIO::flush |
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264 | IO::AIO::max_poll_reqs $nreqs |
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265 | IO::AIO::max_poll_time $seconds |
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266 | IO::AIO::min_parallel $nthreads |
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267 | IO::AIO::max_parallel $nthreads |
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268 | IO::AIO::max_idle $nthreads |
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269 | IO::AIO::idle_timeout $seconds |
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270 | IO::AIO::max_outstanding $maxreqs |
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271 | IO::AIO::nreqs |
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272 | IO::AIO::nready |
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273 | IO::AIO::npending |
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274 | |
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275 | IO::AIO::sendfile $ofh, $ifh, $offset, $count |
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276 | IO::AIO::fadvise $fh, $offset, $len, $advice |
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277 | IO::AIO::madvise $scalar, $offset, $length, $advice |
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278 | IO::AIO::mprotect $scalar, $offset, $length, $protect |
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279 | IO::AIO::munlock $scalar, $offset = 0, $length = undef |
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280 | IO::AIO::munlockall |
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281 | |
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282 | =head2 API NOTES |
83 | |
283 | |
84 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
284 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
85 | with the same name (sans C<aio_>). The arguments are similar or identical, |
285 | with the same name (sans C<aio_>). The arguments are similar or identical, |
86 | and they all accept an additional (and optional) C<$callback> argument |
286 | and they all accept an additional (and optional) C<$callback> argument |
87 | which must be a code reference. This code reference will get called with |
287 | which must be a code reference. This code reference will be called after |
88 | the syscall return code (e.g. most syscalls return C<-1> on error, unlike |
288 | the syscall has been executed in an asynchronous fashion. The results |
89 | perl, which usually delivers "false") as it's sole argument when the given |
289 | of the request will be passed as arguments to the callback (and, if an |
90 | syscall has been executed asynchronously. |
290 | error occured, in C<$!>) - for most requests the syscall return code (e.g. |
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291 | most syscalls return C<-1> on error, unlike perl, which usually delivers |
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292 | "false"). |
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293 | |
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294 | Some requests (such as C<aio_readdir>) pass the actual results and |
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295 | communicate failures by passing C<undef>. |
91 | |
296 | |
92 | All functions expecting a filehandle keep a copy of the filehandle |
297 | All functions expecting a filehandle keep a copy of the filehandle |
93 | internally until the request has finished. |
298 | internally until the request has finished. |
94 | |
299 | |
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300 | All functions return request objects of type L<IO::AIO::REQ> that allow |
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301 | further manipulation of those requests while they are in-flight. |
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302 | |
95 | The pathnames you pass to these routines I<must> be absolute and |
303 | The pathnames you pass to these routines I<should> be absolute. The |
96 | encoded in byte form. The reason for the former is that at the time the |
304 | reason for this is that at the time the request is being executed, the |
97 | request is being executed, the current working directory could have |
305 | current working directory could have changed. Alternatively, you can |
98 | changed. Alternatively, you can make sure that you never change the |
306 | make sure that you never change the current working directory anywhere |
99 | current working directory. |
307 | in the program and then use relative paths. You can also take advantage |
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308 | of IO::AIOs working directory abstraction, that lets you specify paths |
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309 | relative to some previously-opened "working directory object" - see the |
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310 | description of the C<IO::AIO::WD> class later in this document. |
100 | |
311 | |
101 | To encode pathnames to byte form, either make sure you either: a) |
312 | To encode pathnames as octets, either make sure you either: a) always pass |
102 | always pass in filenames you got from outside (command line, readdir |
313 | in filenames you got from outside (command line, readdir etc.) without |
103 | etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
314 | tinkering, b) are in your native filesystem encoding, c) use the Encode |
104 | your pathnames to the locale (or other) encoding in effect in the user |
315 | module and encode your pathnames to the locale (or other) encoding in |
105 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
316 | effect in the user environment, d) use Glib::filename_from_unicode on |
106 | use something else. |
317 | unicode filenames or e) use something else to ensure your scalar has the |
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318 | correct contents. |
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319 | |
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320 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
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321 | handles correctly whether it is set or not. |
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322 | |
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323 | =head2 AIO REQUEST FUNCTIONS |
107 | |
324 | |
108 | =over 4 |
325 | =over 4 |
109 | |
326 | |
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327 | =item $prev_pri = aioreq_pri [$pri] |
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328 | |
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329 | Returns the priority value that would be used for the next request and, if |
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330 | C<$pri> is given, sets the priority for the next aio request. |
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331 | |
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332 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
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333 | and C<4>, respectively. Requests with higher priority will be serviced |
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334 | first. |
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335 | |
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336 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
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337 | functions. |
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338 | |
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339 | Example: open a file with low priority, then read something from it with |
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340 | higher priority so the read request is serviced before other low priority |
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341 | open requests (potentially spamming the cache): |
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342 | |
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343 | aioreq_pri -3; |
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344 | aio_open ..., sub { |
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345 | return unless $_[0]; |
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346 | |
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347 | aioreq_pri -2; |
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348 | aio_read $_[0], ..., sub { |
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|
349 | ... |
|
|
350 | }; |
|
|
351 | }; |
|
|
352 | |
|
|
353 | |
|
|
354 | =item aioreq_nice $pri_adjust |
|
|
355 | |
|
|
356 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
|
357 | priority, so the effect is cumulative. |
|
|
358 | |
|
|
359 | |
110 | =item aio_open $pathname, $flags, $mode, $callback |
360 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
111 | |
361 | |
112 | Asynchronously open or create a file and call the callback with a newly |
362 | Asynchronously open or create a file and call the callback with a newly |
113 | created filehandle for the file. |
363 | created filehandle for the file. |
114 | |
364 | |
115 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
365 | The pathname passed to C<aio_open> must be absolute. See API NOTES, above, |
… | |
… | |
119 | list. They are the same as used by C<sysopen>. |
369 | list. They are the same as used by C<sysopen>. |
120 | |
370 | |
121 | Likewise, C<$mode> specifies the mode of the newly created file, if it |
371 | Likewise, C<$mode> specifies the mode of the newly created file, if it |
122 | didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, |
372 | didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, |
123 | except that it is mandatory (i.e. use C<0> if you don't create new files, |
373 | except that it is mandatory (i.e. use C<0> if you don't create new files, |
124 | and C<0666> or C<0777> if you do). |
374 | and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified |
|
|
375 | by the umask in effect then the request is being executed, so better never |
|
|
376 | change the umask. |
125 | |
377 | |
126 | Example: |
378 | Example: |
127 | |
379 | |
128 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
380 | aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { |
129 | if ($_[0]) { |
381 | if ($_[0]) { |
130 | print "open successful, fh is $_[0]\n"; |
382 | print "open successful, fh is $_[0]\n"; |
131 | ... |
383 | ... |
132 | } else { |
384 | } else { |
133 | die "open failed: $!\n"; |
385 | die "open failed: $!\n"; |
134 | } |
386 | } |
135 | }; |
387 | }; |
136 | |
388 | |
|
|
389 | In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>, |
|
|
390 | C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the |
|
|
391 | following POSIX and non-POSIX constants are available (missing ones on |
|
|
392 | your system are, as usual, C<0>): |
|
|
393 | |
|
|
394 | C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, |
|
|
395 | C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, |
|
|
396 | C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. |
|
|
397 | |
|
|
398 | |
137 | =item aio_close $fh, $callback |
399 | =item aio_close $fh, $callback->($status) |
138 | |
400 | |
139 | Asynchronously close a file and call the callback with the result |
401 | Asynchronously close a file and call the callback with the result |
140 | code. I<WARNING:> although accepted, you should not pass in a perl |
402 | code. |
141 | filehandle here, as perl will likely close the file descriptor another |
|
|
142 | time when the filehandle is destroyed. Normally, you can safely call perls |
|
|
143 | C<close> or just let filehandles go out of scope. |
|
|
144 | |
403 | |
145 | This is supposed to be a bug in the API, so that might change. It's |
404 | Unfortunately, you can't do this to perl. Perl I<insists> very strongly on |
146 | therefore best to avoid this function. |
405 | closing the file descriptor associated with the filehandle itself. |
147 | |
406 | |
|
|
407 | Therefore, C<aio_close> will not close the filehandle - instead it will |
|
|
408 | use dup2 to overwrite the file descriptor with the write-end of a pipe |
|
|
409 | (the pipe fd will be created on demand and will be cached). |
|
|
410 | |
|
|
411 | Or in other words: the file descriptor will be closed, but it will not be |
|
|
412 | free for reuse until the perl filehandle is closed. |
|
|
413 | |
|
|
414 | =cut |
|
|
415 | |
|
|
416 | =item aio_seek $fh, $offset, $whence, $callback->($offs) |
|
|
417 | |
|
|
418 | Seeks the filehandle to the new C<$offset>, similarly to perl'S |
|
|
419 | C<sysseek>. The C<$whence> can use the traditional values (C<0> for |
|
|
420 | C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for |
|
|
421 | C<IO::AIO::SEEK_END>). |
|
|
422 | |
|
|
423 | The resulting absolute offset will be passed to the callback, or C<-1> in |
|
|
424 | case of an error. |
|
|
425 | |
|
|
426 | In theory, the C<$whence> constants could be different than the |
|
|
427 | corresponding values from L<Fcntl>, but perl guarantees they are the same, |
|
|
428 | so don't panic. |
|
|
429 | |
148 | =item aio_read $fh,$offset,$length, $data,$dataoffset,$callback |
430 | =item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
149 | |
431 | |
150 | =item aio_write $fh,$offset,$length, $data,$dataoffset,$callback |
432 | =item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) |
151 | |
433 | |
152 | Reads or writes C<length> bytes from the specified C<fh> and C<offset> |
434 | Reads or writes C<$length> bytes from or to the specified C<$fh> and |
153 | into the scalar given by C<data> and offset C<dataoffset> and calls the |
435 | C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> |
154 | callback without the actual number of bytes read (or -1 on error, just |
436 | and calls the callback without the actual number of bytes read (or -1 on |
155 | like the syscall). |
437 | error, just like the syscall). |
|
|
438 | |
|
|
439 | C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to |
|
|
440 | offset plus the actual number of bytes read. |
|
|
441 | |
|
|
442 | If C<$offset> is undefined, then the current file descriptor offset will |
|
|
443 | be used (and updated), otherwise the file descriptor offset will not be |
|
|
444 | changed by these calls. |
|
|
445 | |
|
|
446 | If C<$length> is undefined in C<aio_write>, use the remaining length of |
|
|
447 | C<$data>. |
|
|
448 | |
|
|
449 | If C<$dataoffset> is less than zero, it will be counted from the end of |
|
|
450 | C<$data>. |
156 | |
451 | |
157 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
452 | The C<$data> scalar I<MUST NOT> be modified in any way while the request |
158 | is outstanding. Modifying it can result in segfaults or WW3 (if the |
453 | is outstanding. Modifying it can result in segfaults or World War III (if |
159 | necessary/optional hardware is installed). |
454 | the necessary/optional hardware is installed). |
160 | |
455 | |
161 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
456 | Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at |
162 | offset C<0> within the scalar: |
457 | offset C<0> within the scalar: |
163 | |
458 | |
164 | aio_read $fh, 7, 15, $buffer, 0, sub { |
459 | aio_read $fh, 7, 15, $buffer, 0, sub { |
165 | $_[0] > 0 or die "read error: $!"; |
460 | $_[0] > 0 or die "read error: $!"; |
166 | print "read $_[0] bytes: <$buffer>\n"; |
461 | print "read $_[0] bytes: <$buffer>\n"; |
167 | }; |
462 | }; |
168 | |
463 | |
|
|
464 | |
169 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback |
465 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
170 | |
466 | |
171 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
467 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
172 | reading at byte offset C<$in_offset>, and starts writing at the current |
468 | reading at byte offset C<$in_offset>, and starts writing at the current |
173 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
469 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
174 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
470 | than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each |
175 | other. |
471 | other. The same C<$in_fh> works fine though, as this function does not |
|
|
472 | move or use the file offset of C<$in_fh>. |
176 | |
473 | |
|
|
474 | Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than |
|
|
475 | are written, and there is no way to find out how many more bytes have been |
|
|
476 | read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the |
|
|
477 | number of bytes written to C<$out_fh>. Only if the result value equals |
|
|
478 | C<$length> one can assume that C<$length> bytes have been read. |
|
|
479 | |
|
|
480 | Unlike with other C<aio_> functions, it makes a lot of sense to use |
|
|
481 | C<aio_sendfile> on non-blocking sockets, as long as one end (typically |
|
|
482 | the C<$in_fh>) is a file - the file I/O will then be asynchronous, while |
|
|
483 | the socket I/O will be non-blocking. Note, however, that you can run |
|
|
484 | into a trap where C<aio_sendfile> reads some data with readahead, then |
|
|
485 | fails to write all data, and when the socket is ready the next time, the |
|
|
486 | data in the cache is already lost, forcing C<aio_sendfile> to again hit |
|
|
487 | the disk. Explicit C<aio_read> + C<aio_write> let's you better control |
|
|
488 | resource usage. |
|
|
489 | |
177 | This call tries to make use of a native C<sendfile> syscall to provide |
490 | This call tries to make use of a native C<sendfile>-like syscall to |
178 | zero-copy operation. For this to work, C<$out_fh> should refer to a |
491 | provide zero-copy operation. For this to work, C<$out_fh> should refer to |
179 | socket, and C<$in_fh> should refer to mmap'able file. |
492 | a socket, and C<$in_fh> should refer to an mmap'able file. |
180 | |
493 | |
181 | If the native sendfile call fails or is not implemented, it will be |
494 | If a native sendfile cannot be found or it fails with C<ENOSYS>, |
182 | emulated, so you can call C<aio_sendfile> on any type of filehandle |
495 | C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or |
|
|
496 | C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any |
183 | regardless of the limitations of the operating system. |
497 | type of filehandle regardless of the limitations of the operating system. |
184 | |
498 | |
185 | Please note, however, that C<aio_sendfile> can read more bytes from |
499 | As native sendfile syscalls (as practically any non-POSIX interface hacked |
186 | C<$in_fh> than are written, and there is no way to find out how many |
500 | together in a hurry to improve benchmark numbers) tend to be rather buggy |
187 | bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only |
501 | on many systems, this implementation tries to work around some known bugs |
188 | provides the number of bytes written to C<$out_fh>. Only if the result |
502 | in Linux and FreeBSD kernels (probably others, too), but that might fail, |
189 | value equals C<$length> one can assume that C<$length> bytes have been |
503 | so you really really should check the return value of C<aio_sendfile> - |
190 | read. |
504 | fewre bytes than expected might have been transferred. |
191 | |
505 | |
|
|
506 | |
192 | =item aio_readahead $fh,$offset,$length, $callback |
507 | =item aio_readahead $fh,$offset,$length, $callback->($retval) |
193 | |
508 | |
194 | C<aio_readahead> populates the page cache with data from a file so that |
509 | C<aio_readahead> populates the page cache with data from a file so that |
195 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
510 | subsequent reads from that file will not block on disk I/O. The C<$offset> |
196 | argument specifies the starting point from which data is to be read and |
511 | argument specifies the starting point from which data is to be read and |
197 | C<$length> specifies the number of bytes to be read. I/O is performed in |
512 | C<$length> specifies the number of bytes to be read. I/O is performed in |
… | |
… | |
201 | file. The current file offset of the file is left unchanged. |
516 | file. The current file offset of the file is left unchanged. |
202 | |
517 | |
203 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
518 | If that syscall doesn't exist (likely if your OS isn't Linux) it will be |
204 | emulated by simply reading the data, which would have a similar effect. |
519 | emulated by simply reading the data, which would have a similar effect. |
205 | |
520 | |
|
|
521 | |
206 | =item aio_stat $fh_or_path, $callback |
522 | =item aio_stat $fh_or_path, $callback->($status) |
207 | |
523 | |
208 | =item aio_lstat $fh, $callback |
524 | =item aio_lstat $fh, $callback->($status) |
209 | |
525 | |
210 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
526 | Works like perl's C<stat> or C<lstat> in void context. The callback will |
211 | be called after the stat and the results will be available using C<stat _> |
527 | be called after the stat and the results will be available using C<stat _> |
212 | or C<-s _> etc... |
528 | or C<-s _> etc... |
213 | |
529 | |
… | |
… | |
215 | for an explanation. |
531 | for an explanation. |
216 | |
532 | |
217 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
533 | Currently, the stats are always 64-bit-stats, i.e. instead of returning an |
218 | error when stat'ing a large file, the results will be silently truncated |
534 | error when stat'ing a large file, the results will be silently truncated |
219 | unless perl itself is compiled with large file support. |
535 | unless perl itself is compiled with large file support. |
|
|
536 | |
|
|
537 | To help interpret the mode and dev/rdev stat values, IO::AIO offers the |
|
|
538 | following constants and functions (if not implemented, the constants will |
|
|
539 | be C<0> and the functions will either C<croak> or fall back on traditional |
|
|
540 | behaviour). |
|
|
541 | |
|
|
542 | C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, |
|
|
543 | C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, |
|
|
544 | C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. |
220 | |
545 | |
221 | Example: Print the length of F</etc/passwd>: |
546 | Example: Print the length of F</etc/passwd>: |
222 | |
547 | |
223 | aio_stat "/etc/passwd", sub { |
548 | aio_stat "/etc/passwd", sub { |
224 | $_[0] and die "stat failed: $!"; |
549 | $_[0] and die "stat failed: $!"; |
225 | print "size is ", -s _, "\n"; |
550 | print "size is ", -s _, "\n"; |
226 | }; |
551 | }; |
227 | |
552 | |
|
|
553 | |
|
|
554 | =item aio_statvfs $fh_or_path, $callback->($statvfs) |
|
|
555 | |
|
|
556 | Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on |
|
|
557 | whether a file handle or path was passed. |
|
|
558 | |
|
|
559 | On success, the callback is passed a hash reference with the following |
|
|
560 | members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>, |
|
|
561 | C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef> |
|
|
562 | is passed. |
|
|
563 | |
|
|
564 | The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and |
|
|
565 | C<ST_NOSUID>. |
|
|
566 | |
|
|
567 | The following non-POSIX IO::AIO::ST_* flag masks are defined to |
|
|
568 | their correct value when available, or to C<0> on systems that do |
|
|
569 | not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>, |
|
|
570 | C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>, |
|
|
571 | C<ST_NODIRATIME> and C<ST_RELATIME>. |
|
|
572 | |
|
|
573 | Example: stat C</wd> and dump out the data if successful. |
|
|
574 | |
|
|
575 | aio_statvfs "/wd", sub { |
|
|
576 | my $f = $_[0] |
|
|
577 | or die "statvfs: $!"; |
|
|
578 | |
|
|
579 | use Data::Dumper; |
|
|
580 | say Dumper $f; |
|
|
581 | }; |
|
|
582 | |
|
|
583 | # result: |
|
|
584 | { |
|
|
585 | bsize => 1024, |
|
|
586 | bfree => 4333064312, |
|
|
587 | blocks => 10253828096, |
|
|
588 | files => 2050765568, |
|
|
589 | flag => 4096, |
|
|
590 | favail => 2042092649, |
|
|
591 | bavail => 4333064312, |
|
|
592 | ffree => 2042092649, |
|
|
593 | namemax => 255, |
|
|
594 | frsize => 1024, |
|
|
595 | fsid => 1810 |
|
|
596 | } |
|
|
597 | |
|
|
598 | |
|
|
599 | =item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) |
|
|
600 | |
|
|
601 | Works like perl's C<utime> function (including the special case of $atime |
|
|
602 | and $mtime being undef). Fractional times are supported if the underlying |
|
|
603 | syscalls support them. |
|
|
604 | |
|
|
605 | When called with a pathname, uses utimes(2) if available, otherwise |
|
|
606 | utime(2). If called on a file descriptor, uses futimes(2) if available, |
|
|
607 | otherwise returns ENOSYS, so this is not portable. |
|
|
608 | |
|
|
609 | Examples: |
|
|
610 | |
|
|
611 | # set atime and mtime to current time (basically touch(1)): |
|
|
612 | aio_utime "path", undef, undef; |
|
|
613 | # set atime to current time and mtime to beginning of the epoch: |
|
|
614 | aio_utime "path", time, undef; # undef==0 |
|
|
615 | |
|
|
616 | |
|
|
617 | =item aio_chown $fh_or_path, $uid, $gid, $callback->($status) |
|
|
618 | |
|
|
619 | Works like perl's C<chown> function, except that C<undef> for either $uid |
|
|
620 | or $gid is being interpreted as "do not change" (but -1 can also be used). |
|
|
621 | |
|
|
622 | Examples: |
|
|
623 | |
|
|
624 | # same as "chown root path" in the shell: |
|
|
625 | aio_chown "path", 0, -1; |
|
|
626 | # same as above: |
|
|
627 | aio_chown "path", 0, undef; |
|
|
628 | |
|
|
629 | |
|
|
630 | =item aio_truncate $fh_or_path, $offset, $callback->($status) |
|
|
631 | |
|
|
632 | Works like truncate(2) or ftruncate(2). |
|
|
633 | |
|
|
634 | |
|
|
635 | =item aio_chmod $fh_or_path, $mode, $callback->($status) |
|
|
636 | |
|
|
637 | Works like perl's C<chmod> function. |
|
|
638 | |
|
|
639 | |
228 | =item aio_unlink $pathname, $callback |
640 | =item aio_unlink $pathname, $callback->($status) |
229 | |
641 | |
230 | Asynchronously unlink (delete) a file and call the callback with the |
642 | Asynchronously unlink (delete) a file and call the callback with the |
231 | result code. |
643 | result code. |
232 | |
644 | |
|
|
645 | |
|
|
646 | =item aio_mknod $pathname, $mode, $dev, $callback->($status) |
|
|
647 | |
|
|
648 | [EXPERIMENTAL] |
|
|
649 | |
|
|
650 | Asynchronously create a device node (or fifo). See mknod(2). |
|
|
651 | |
|
|
652 | The only (POSIX-) portable way of calling this function is: |
|
|
653 | |
|
|
654 | aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
655 | |
|
|
656 | See C<aio_stat> for info about some potentially helpful extra constants |
|
|
657 | and functions. |
|
|
658 | |
|
|
659 | =item aio_link $srcpath, $dstpath, $callback->($status) |
|
|
660 | |
|
|
661 | Asynchronously create a new link to the existing object at C<$srcpath> at |
|
|
662 | the path C<$dstpath> and call the callback with the result code. |
|
|
663 | |
|
|
664 | |
|
|
665 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
|
|
666 | |
|
|
667 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
|
|
668 | the path C<$dstpath> and call the callback with the result code. |
|
|
669 | |
|
|
670 | |
|
|
671 | =item aio_readlink $pathname, $callback->($link) |
|
|
672 | |
|
|
673 | Asynchronously read the symlink specified by C<$path> and pass it to |
|
|
674 | the callback. If an error occurs, nothing or undef gets passed to the |
|
|
675 | callback. |
|
|
676 | |
|
|
677 | |
|
|
678 | =item aio_realpath $pathname, $callback->($path) |
|
|
679 | |
|
|
680 | Asynchronously make the path absolute and resolve any symlinks in |
|
|
681 | C<$path>. The resulting path only consists of directories (Same as |
|
|
682 | L<Cwd::realpath>). |
|
|
683 | |
|
|
684 | This request can be used to get the absolute path of the current working |
|
|
685 | directory by passing it a path of F<.> (a single dot). |
|
|
686 | |
|
|
687 | |
|
|
688 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
|
|
689 | |
|
|
690 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
|
|
691 | rename(2) and call the callback with the result code. |
|
|
692 | |
|
|
693 | |
|
|
694 | =item aio_mkdir $pathname, $mode, $callback->($status) |
|
|
695 | |
|
|
696 | Asynchronously mkdir (create) a directory and call the callback with |
|
|
697 | the result code. C<$mode> will be modified by the umask at the time the |
|
|
698 | request is executed, so do not change your umask. |
|
|
699 | |
|
|
700 | |
233 | =item aio_rmdir $pathname, $callback |
701 | =item aio_rmdir $pathname, $callback->($status) |
234 | |
702 | |
235 | Asynchronously rmdir (delete) a directory and call the callback with the |
703 | Asynchronously rmdir (delete) a directory and call the callback with the |
236 | result code. |
704 | result code. |
237 | |
705 | |
|
|
706 | |
238 | =item aio_readdir $pathname $callback |
707 | =item aio_readdir $pathname, $callback->($entries) |
239 | |
708 | |
240 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
709 | Unlike the POSIX call of the same name, C<aio_readdir> reads an entire |
241 | directory (i.e. opendir + readdir + closedir). The entries will not be |
710 | directory (i.e. opendir + readdir + closedir). The entries will not be |
242 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
711 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
243 | |
712 | |
244 | The callback a single argument which is either C<undef> or an array-ref |
713 | The callback is passed a single argument which is either C<undef> or an |
245 | with the filenames. |
714 | array-ref with the filenames. |
246 | |
715 | |
|
|
716 | |
|
|
717 | =item aio_readdirx $pathname, $flags, $callback->($entries, $flags) |
|
|
718 | |
|
|
719 | Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to |
|
|
720 | tune behaviour and output format. In case of an error, C<$entries> will be |
|
|
721 | C<undef>. |
|
|
722 | |
|
|
723 | The flags are a combination of the following constants, ORed together (the |
|
|
724 | flags will also be passed to the callback, possibly modified): |
|
|
725 | |
|
|
726 | =over 4 |
|
|
727 | |
|
|
728 | =item IO::AIO::READDIR_DENTS |
|
|
729 | |
|
|
730 | When this flag is off, then the callback gets an arrayref consisting of |
|
|
731 | names only (as with C<aio_readdir>), otherwise it gets an arrayref with |
|
|
732 | C<[$name, $type, $inode]> arrayrefs, each describing a single directory |
|
|
733 | entry in more detail. |
|
|
734 | |
|
|
735 | C<$name> is the name of the entry. |
|
|
736 | |
|
|
737 | C<$type> is one of the C<IO::AIO::DT_xxx> constants: |
|
|
738 | |
|
|
739 | C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, |
|
|
740 | C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, |
|
|
741 | C<IO::AIO::DT_WHT>. |
|
|
742 | |
|
|
743 | C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to |
|
|
744 | know, you have to run stat yourself. Also, for speed reasons, the C<$type> |
|
|
745 | scalars are read-only: you can not modify them. |
|
|
746 | |
|
|
747 | C<$inode> is the inode number (which might not be exact on systems with 64 |
|
|
748 | bit inode numbers and 32 bit perls). This field has unspecified content on |
|
|
749 | systems that do not deliver the inode information. |
|
|
750 | |
|
|
751 | =item IO::AIO::READDIR_DIRS_FIRST |
|
|
752 | |
|
|
753 | When this flag is set, then the names will be returned in an order where |
|
|
754 | likely directories come first, in optimal stat order. This is useful when |
|
|
755 | you need to quickly find directories, or you want to find all directories |
|
|
756 | while avoiding to stat() each entry. |
|
|
757 | |
|
|
758 | If the system returns type information in readdir, then this is used |
|
|
759 | to find directories directly. Otherwise, likely directories are names |
|
|
760 | beginning with ".", or otherwise names with no dots, of which names with |
|
|
761 | short names are tried first. |
|
|
762 | |
|
|
763 | =item IO::AIO::READDIR_STAT_ORDER |
|
|
764 | |
|
|
765 | When this flag is set, then the names will be returned in an order |
|
|
766 | suitable for stat()'ing each one. That is, when you plan to stat() |
|
|
767 | all files in the given directory, then the returned order will likely |
|
|
768 | be fastest. |
|
|
769 | |
|
|
770 | If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then |
|
|
771 | the likely dirs come first, resulting in a less optimal stat order. |
|
|
772 | |
|
|
773 | =item IO::AIO::READDIR_FOUND_UNKNOWN |
|
|
774 | |
|
|
775 | This flag should not be set when calling C<aio_readdirx>. Instead, it |
|
|
776 | is being set by C<aio_readdirx>, when any of the C<$type>'s found were |
|
|
777 | C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all |
|
|
778 | C<$type>'s are known, which can be used to speed up some algorithms. |
|
|
779 | |
|
|
780 | =back |
|
|
781 | |
|
|
782 | |
|
|
783 | =item aio_load $pathname, $data, $callback->($status) |
|
|
784 | |
|
|
785 | This is a composite request that tries to fully load the given file into |
|
|
786 | memory. Status is the same as with aio_read. |
|
|
787 | |
|
|
788 | =cut |
|
|
789 | |
|
|
790 | sub aio_load($$;$) { |
|
|
791 | my ($path, undef, $cb) = @_; |
|
|
792 | my $data = \$_[1]; |
|
|
793 | |
|
|
794 | my $pri = aioreq_pri; |
|
|
795 | my $grp = aio_group $cb; |
|
|
796 | |
|
|
797 | aioreq_pri $pri; |
|
|
798 | add $grp aio_open $path, O_RDONLY, 0, sub { |
|
|
799 | my $fh = shift |
|
|
800 | or return $grp->result (-1); |
|
|
801 | |
|
|
802 | aioreq_pri $pri; |
|
|
803 | add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { |
|
|
804 | $grp->result ($_[0]); |
|
|
805 | }; |
|
|
806 | }; |
|
|
807 | |
|
|
808 | $grp |
|
|
809 | } |
|
|
810 | |
|
|
811 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
812 | |
|
|
813 | Try to copy the I<file> (directories not supported as either source or |
|
|
814 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
815 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
|
|
816 | |
|
|
817 | This is a composite request that creates the destination file with |
|
|
818 | mode 0200 and copies the contents of the source file into it using |
|
|
819 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
|
|
820 | uid/gid, in that order. |
|
|
821 | |
|
|
822 | If an error occurs, the partial destination file will be unlinked, if |
|
|
823 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
824 | errors are being ignored. |
|
|
825 | |
|
|
826 | =cut |
|
|
827 | |
|
|
828 | sub aio_copy($$;$) { |
|
|
829 | my ($src, $dst, $cb) = @_; |
|
|
830 | |
|
|
831 | my $pri = aioreq_pri; |
|
|
832 | my $grp = aio_group $cb; |
|
|
833 | |
|
|
834 | aioreq_pri $pri; |
|
|
835 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
836 | if (my $src_fh = $_[0]) { |
|
|
837 | my @stat = stat $src_fh; # hmm, might block over nfs? |
|
|
838 | |
|
|
839 | aioreq_pri $pri; |
|
|
840 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
841 | if (my $dst_fh = $_[0]) { |
|
|
842 | aioreq_pri $pri; |
|
|
843 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
844 | if ($_[0] == $stat[7]) { |
|
|
845 | $grp->result (0); |
|
|
846 | close $src_fh; |
|
|
847 | |
|
|
848 | my $ch = sub { |
|
|
849 | aioreq_pri $pri; |
|
|
850 | add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub { |
|
|
851 | aioreq_pri $pri; |
|
|
852 | add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub { |
|
|
853 | aioreq_pri $pri; |
|
|
854 | add $grp aio_close $dst_fh; |
|
|
855 | } |
|
|
856 | }; |
|
|
857 | }; |
|
|
858 | |
|
|
859 | aioreq_pri $pri; |
|
|
860 | add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub { |
|
|
861 | if ($_[0] < 0 && $! == ENOSYS) { |
|
|
862 | aioreq_pri $pri; |
|
|
863 | add $grp aio_utime $dst, $stat[8], $stat[9], $ch; |
|
|
864 | } else { |
|
|
865 | $ch->(); |
|
|
866 | } |
|
|
867 | }; |
|
|
868 | } else { |
|
|
869 | $grp->result (-1); |
|
|
870 | close $src_fh; |
|
|
871 | close $dst_fh; |
|
|
872 | |
|
|
873 | aioreq $pri; |
|
|
874 | add $grp aio_unlink $dst; |
|
|
875 | } |
|
|
876 | }; |
|
|
877 | } else { |
|
|
878 | $grp->result (-1); |
|
|
879 | } |
|
|
880 | }, |
|
|
881 | |
|
|
882 | } else { |
|
|
883 | $grp->result (-1); |
|
|
884 | } |
|
|
885 | }; |
|
|
886 | |
|
|
887 | $grp |
|
|
888 | } |
|
|
889 | |
|
|
890 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
891 | |
|
|
892 | Try to move the I<file> (directories not supported as either source or |
|
|
893 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
894 | a status of C<0> (ok) or C<-1> (error, see C<$!>). |
|
|
895 | |
|
|
896 | This is a composite request that tries to rename(2) the file first; if |
|
|
897 | rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
898 | that is successful, unlinks the C<$srcpath>. |
|
|
899 | |
|
|
900 | =cut |
|
|
901 | |
|
|
902 | sub aio_move($$;$) { |
|
|
903 | my ($src, $dst, $cb) = @_; |
|
|
904 | |
|
|
905 | my $pri = aioreq_pri; |
|
|
906 | my $grp = aio_group $cb; |
|
|
907 | |
|
|
908 | aioreq_pri $pri; |
|
|
909 | add $grp aio_rename $src, $dst, sub { |
|
|
910 | if ($_[0] && $! == EXDEV) { |
|
|
911 | aioreq_pri $pri; |
|
|
912 | add $grp aio_copy $src, $dst, sub { |
|
|
913 | $grp->result ($_[0]); |
|
|
914 | |
|
|
915 | unless ($_[0]) { |
|
|
916 | aioreq_pri $pri; |
|
|
917 | add $grp aio_unlink $src; |
|
|
918 | } |
|
|
919 | }; |
|
|
920 | } else { |
|
|
921 | $grp->result ($_[0]); |
|
|
922 | } |
|
|
923 | }; |
|
|
924 | |
|
|
925 | $grp |
|
|
926 | } |
|
|
927 | |
|
|
928 | =item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) |
|
|
929 | |
|
|
930 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
|
|
931 | efficiently separate the entries of directory C<$path> into two sets of |
|
|
932 | names, directories you can recurse into (directories), and ones you cannot |
|
|
933 | recurse into (everything else, including symlinks to directories). |
|
|
934 | |
|
|
935 | C<aio_scandir> is a composite request that creates of many sub requests_ |
|
|
936 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
|
|
937 | this function generates. If it is C<< <= 0 >>, then a suitable default |
|
|
938 | will be chosen (currently 4). |
|
|
939 | |
|
|
940 | On error, the callback is called without arguments, otherwise it receives |
|
|
941 | two array-refs with path-relative entry names. |
|
|
942 | |
|
|
943 | Example: |
|
|
944 | |
|
|
945 | aio_scandir $dir, 0, sub { |
|
|
946 | my ($dirs, $nondirs) = @_; |
|
|
947 | print "real directories: @$dirs\n"; |
|
|
948 | print "everything else: @$nondirs\n"; |
|
|
949 | }; |
|
|
950 | |
|
|
951 | Implementation notes. |
|
|
952 | |
|
|
953 | The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. |
|
|
954 | |
|
|
955 | If readdir returns file type information, then this is used directly to |
|
|
956 | find directories. |
|
|
957 | |
|
|
958 | Otherwise, after reading the directory, the modification time, size etc. |
|
|
959 | of the directory before and after the readdir is checked, and if they |
|
|
960 | match (and isn't the current time), the link count will be used to decide |
|
|
961 | how many entries are directories (if >= 2). Otherwise, no knowledge of the |
|
|
962 | number of subdirectories will be assumed. |
|
|
963 | |
|
|
964 | Then entries will be sorted into likely directories a non-initial dot |
|
|
965 | currently) and likely non-directories (see C<aio_readdirx>). Then every |
|
|
966 | entry plus an appended C</.> will be C<stat>'ed, likely directories first, |
|
|
967 | in order of their inode numbers. If that succeeds, it assumes that the |
|
|
968 | entry is a directory or a symlink to directory (which will be checked |
|
|
969 | separately). This is often faster than stat'ing the entry itself because |
|
|
970 | filesystems might detect the type of the entry without reading the inode |
|
|
971 | data (e.g. ext2fs filetype feature), even on systems that cannot return |
|
|
972 | the filetype information on readdir. |
|
|
973 | |
|
|
974 | If the known number of directories (link count - 2) has been reached, the |
|
|
975 | rest of the entries is assumed to be non-directories. |
|
|
976 | |
|
|
977 | This only works with certainty on POSIX (= UNIX) filesystems, which |
|
|
978 | fortunately are the vast majority of filesystems around. |
|
|
979 | |
|
|
980 | It will also likely work on non-POSIX filesystems with reduced efficiency |
|
|
981 | as those tend to return 0 or 1 as link counts, which disables the |
|
|
982 | directory counting heuristic. |
|
|
983 | |
|
|
984 | =cut |
|
|
985 | |
|
|
986 | sub aio_scandir($$;$) { |
|
|
987 | my ($path, $maxreq, $cb) = @_; |
|
|
988 | |
|
|
989 | my $pri = aioreq_pri; |
|
|
990 | |
|
|
991 | my $grp = aio_group $cb; |
|
|
992 | |
|
|
993 | $maxreq = 4 if $maxreq <= 0; |
|
|
994 | |
|
|
995 | # get a wd object |
|
|
996 | aioreq_pri $pri; |
|
|
997 | add $grp aio_wd $path, sub { |
|
|
998 | $_[0] |
|
|
999 | or return $grp->result (); |
|
|
1000 | |
|
|
1001 | my $wd = [shift, "."]; |
|
|
1002 | |
|
|
1003 | # stat once |
|
|
1004 | aioreq_pri $pri; |
|
|
1005 | add $grp aio_stat $wd, sub { |
|
|
1006 | return $grp->result () if $_[0]; |
|
|
1007 | my $now = time; |
|
|
1008 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
|
|
1009 | |
|
|
1010 | # read the directory entries |
|
|
1011 | aioreq_pri $pri; |
|
|
1012 | add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { |
|
|
1013 | my $entries = shift |
|
|
1014 | or return $grp->result (); |
|
|
1015 | |
|
|
1016 | # stat the dir another time |
|
|
1017 | aioreq_pri $pri; |
|
|
1018 | add $grp aio_stat $wd, sub { |
|
|
1019 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
|
|
1020 | |
|
|
1021 | my $ndirs; |
|
|
1022 | |
|
|
1023 | # take the slow route if anything looks fishy |
|
|
1024 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
|
|
1025 | $ndirs = -1; |
|
|
1026 | } else { |
|
|
1027 | # if nlink == 2, we are finished |
|
|
1028 | # for non-posix-fs's, we rely on nlink < 2 |
|
|
1029 | $ndirs = (stat _)[3] - 2 |
|
|
1030 | or return $grp->result ([], $entries); |
|
|
1031 | } |
|
|
1032 | |
|
|
1033 | my (@dirs, @nondirs); |
|
|
1034 | |
|
|
1035 | my $statgrp = add $grp aio_group sub { |
|
|
1036 | $grp->result (\@dirs, \@nondirs); |
|
|
1037 | }; |
|
|
1038 | |
|
|
1039 | limit $statgrp $maxreq; |
|
|
1040 | feed $statgrp sub { |
|
|
1041 | return unless @$entries; |
|
|
1042 | my $entry = shift @$entries; |
|
|
1043 | |
|
|
1044 | aioreq_pri $pri; |
|
|
1045 | $wd->[1] = "$entry/."; |
|
|
1046 | add $statgrp aio_stat $wd, sub { |
|
|
1047 | if ($_[0] < 0) { |
|
|
1048 | push @nondirs, $entry; |
|
|
1049 | } else { |
|
|
1050 | # need to check for real directory |
|
|
1051 | aioreq_pri $pri; |
|
|
1052 | $wd->[1] = $entry; |
|
|
1053 | add $statgrp aio_lstat $wd, sub { |
|
|
1054 | if (-d _) { |
|
|
1055 | push @dirs, $entry; |
|
|
1056 | |
|
|
1057 | unless (--$ndirs) { |
|
|
1058 | push @nondirs, @$entries; |
|
|
1059 | feed $statgrp; |
|
|
1060 | } |
|
|
1061 | } else { |
|
|
1062 | push @nondirs, $entry; |
|
|
1063 | } |
|
|
1064 | } |
|
|
1065 | } |
|
|
1066 | }; |
|
|
1067 | }; |
|
|
1068 | }; |
|
|
1069 | }; |
|
|
1070 | }; |
|
|
1071 | }; |
|
|
1072 | |
|
|
1073 | $grp |
|
|
1074 | } |
|
|
1075 | |
|
|
1076 | =item aio_rmtree $pathname, $callback->($status) |
|
|
1077 | |
|
|
1078 | Delete a directory tree starting (and including) C<$path>, return the |
|
|
1079 | status of the final C<rmdir> only. This is a composite request that |
|
|
1080 | uses C<aio_scandir> to recurse into and rmdir directories, and unlink |
|
|
1081 | everything else. |
|
|
1082 | |
|
|
1083 | =cut |
|
|
1084 | |
|
|
1085 | sub aio_rmtree; |
|
|
1086 | sub aio_rmtree($;$) { |
|
|
1087 | my ($path, $cb) = @_; |
|
|
1088 | |
|
|
1089 | my $pri = aioreq_pri; |
|
|
1090 | my $grp = aio_group $cb; |
|
|
1091 | |
|
|
1092 | aioreq_pri $pri; |
|
|
1093 | add $grp aio_scandir $path, 0, sub { |
|
|
1094 | my ($dirs, $nondirs) = @_; |
|
|
1095 | |
|
|
1096 | my $dirgrp = aio_group sub { |
|
|
1097 | add $grp aio_rmdir $path, sub { |
|
|
1098 | $grp->result ($_[0]); |
|
|
1099 | }; |
|
|
1100 | }; |
|
|
1101 | |
|
|
1102 | (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs; |
|
|
1103 | (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs; |
|
|
1104 | |
|
|
1105 | add $grp $dirgrp; |
|
|
1106 | }; |
|
|
1107 | |
|
|
1108 | $grp |
|
|
1109 | } |
|
|
1110 | |
|
|
1111 | =item aio_sync $callback->($status) |
|
|
1112 | |
|
|
1113 | Asynchronously call sync and call the callback when finished. |
|
|
1114 | |
247 | =item aio_fsync $fh, $callback |
1115 | =item aio_fsync $fh, $callback->($status) |
248 | |
1116 | |
249 | Asynchronously call fsync on the given filehandle and call the callback |
1117 | Asynchronously call fsync on the given filehandle and call the callback |
250 | with the fsync result code. |
1118 | with the fsync result code. |
251 | |
1119 | |
252 | =item aio_fdatasync $fh, $callback |
1120 | =item aio_fdatasync $fh, $callback->($status) |
253 | |
1121 | |
254 | Asynchronously call fdatasync on the given filehandle and call the |
1122 | Asynchronously call fdatasync on the given filehandle and call the |
255 | callback with the fdatasync result code. |
1123 | callback with the fdatasync result code. |
256 | |
1124 | |
257 | If this call isn't available because your OS lacks it or it couldn't be |
1125 | If this call isn't available because your OS lacks it or it couldn't be |
258 | detected, it will be emulated by calling C<fsync> instead. |
1126 | detected, it will be emulated by calling C<fsync> instead. |
259 | |
1127 | |
|
|
1128 | =item aio_syncfs $fh, $callback->($status) |
|
|
1129 | |
|
|
1130 | Asynchronously call the syncfs syscall to sync the filesystem associated |
|
|
1131 | to the given filehandle and call the callback with the syncfs result |
|
|
1132 | code. If syncfs is not available, calls sync(), but returns C<-1> and sets |
|
|
1133 | errno to C<ENOSYS> nevertheless. |
|
|
1134 | |
|
|
1135 | =item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) |
|
|
1136 | |
|
|
1137 | Sync the data portion of the file specified by C<$offset> and C<$length> |
|
|
1138 | to disk (but NOT the metadata), by calling the Linux-specific |
|
|
1139 | sync_file_range call. If sync_file_range is not available or it returns |
|
|
1140 | ENOSYS, then fdatasync or fsync is being substituted. |
|
|
1141 | |
|
|
1142 | C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, |
|
|
1143 | C<IO::AIO::SYNC_FILE_RANGE_WRITE> and |
|
|
1144 | C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range |
|
|
1145 | manpage for details. |
|
|
1146 | |
|
|
1147 | =item aio_pathsync $pathname, $callback->($status) |
|
|
1148 | |
|
|
1149 | This request tries to open, fsync and close the given path. This is a |
|
|
1150 | composite request intended to sync directories after directory operations |
|
|
1151 | (E.g. rename). This might not work on all operating systems or have any |
|
|
1152 | specific effect, but usually it makes sure that directory changes get |
|
|
1153 | written to disc. It works for anything that can be opened for read-only, |
|
|
1154 | not just directories. |
|
|
1155 | |
|
|
1156 | Future versions of this function might fall back to other methods when |
|
|
1157 | C<fsync> on the directory fails (such as calling C<sync>). |
|
|
1158 | |
|
|
1159 | Passes C<0> when everything went ok, and C<-1> on error. |
|
|
1160 | |
|
|
1161 | =cut |
|
|
1162 | |
|
|
1163 | sub aio_pathsync($;$) { |
|
|
1164 | my ($path, $cb) = @_; |
|
|
1165 | |
|
|
1166 | my $pri = aioreq_pri; |
|
|
1167 | my $grp = aio_group $cb; |
|
|
1168 | |
|
|
1169 | aioreq_pri $pri; |
|
|
1170 | add $grp aio_open $path, O_RDONLY, 0, sub { |
|
|
1171 | my ($fh) = @_; |
|
|
1172 | if ($fh) { |
|
|
1173 | aioreq_pri $pri; |
|
|
1174 | add $grp aio_fsync $fh, sub { |
|
|
1175 | $grp->result ($_[0]); |
|
|
1176 | |
|
|
1177 | aioreq_pri $pri; |
|
|
1178 | add $grp aio_close $fh; |
|
|
1179 | }; |
|
|
1180 | } else { |
|
|
1181 | $grp->result (-1); |
|
|
1182 | } |
|
|
1183 | }; |
|
|
1184 | |
|
|
1185 | $grp |
|
|
1186 | } |
|
|
1187 | |
|
|
1188 | =item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1189 | |
|
|
1190 | This is a rather advanced IO::AIO call, which only works on mmap(2)ed |
|
|
1191 | scalars (see the C<IO::AIO::mmap> function, although it also works on data |
|
|
1192 | scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the |
|
|
1193 | scalar must only be modified in-place while an aio operation is pending on |
|
|
1194 | it). |
|
|
1195 | |
|
|
1196 | It calls the C<msync> function of your OS, if available, with the memory |
|
|
1197 | area starting at C<$offset> in the string and ending C<$length> bytes |
|
|
1198 | later. If C<$length> is negative, counts from the end, and if C<$length> |
|
|
1199 | is C<undef>, then it goes till the end of the string. The flags can be |
|
|
1200 | a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and |
|
|
1201 | C<IO::AIO::MS_SYNC>. |
|
|
1202 | |
|
|
1203 | =item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) |
|
|
1204 | |
|
|
1205 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1206 | scalars. |
|
|
1207 | |
|
|
1208 | It touches (reads or writes) all memory pages in the specified |
|
|
1209 | range inside the scalar. All caveats and parameters are the same |
|
|
1210 | as for C<aio_msync>, above, except for flags, which must be either |
|
|
1211 | C<0> (which reads all pages and ensures they are instantiated) or |
|
|
1212 | C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and |
|
|
1213 | writing an octet from it, which dirties the page). |
|
|
1214 | |
|
|
1215 | =item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) |
|
|
1216 | |
|
|
1217 | This is a rather advanced IO::AIO call, which works best on mmap(2)ed |
|
|
1218 | scalars. |
|
|
1219 | |
|
|
1220 | It reads in all the pages of the underlying storage into memory (if any) |
|
|
1221 | and locks them, so they are not getting swapped/paged out or removed. |
|
|
1222 | |
|
|
1223 | If C<$length> is undefined, then the scalar will be locked till the end. |
|
|
1224 | |
|
|
1225 | On systems that do not implement C<mlock>, this function returns C<-1> |
|
|
1226 | and sets errno to C<ENOSYS>. |
|
|
1227 | |
|
|
1228 | Note that the corresponding C<munlock> is synchronous and is |
|
|
1229 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1230 | |
|
|
1231 | Example: open a file, mmap and mlock it - both will be undone when |
|
|
1232 | C<$data> gets destroyed. |
|
|
1233 | |
|
|
1234 | open my $fh, "<", $path or die "$path: $!"; |
|
|
1235 | my $data; |
|
|
1236 | IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; |
|
|
1237 | aio_mlock $data; # mlock in background |
|
|
1238 | |
|
|
1239 | =item aio_mlockall $flags, $callback->($status) |
|
|
1240 | |
|
|
1241 | Calls the C<mlockall> function with the given C<$flags> (a combination of |
|
|
1242 | C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). |
|
|
1243 | |
|
|
1244 | On systems that do not implement C<mlockall>, this function returns C<-1> |
|
|
1245 | and sets errno to C<ENOSYS>. |
|
|
1246 | |
|
|
1247 | Note that the corresponding C<munlockall> is synchronous and is |
|
|
1248 | documented under L<MISCELLANEOUS FUNCTIONS>. |
|
|
1249 | |
|
|
1250 | Example: asynchronously lock all current and future pages into memory. |
|
|
1251 | |
|
|
1252 | aio_mlockall IO::AIO::MCL_FUTURE; |
|
|
1253 | |
|
|
1254 | =item aio_group $callback->(...) |
|
|
1255 | |
|
|
1256 | This is a very special aio request: Instead of doing something, it is a |
|
|
1257 | container for other aio requests, which is useful if you want to bundle |
|
|
1258 | many requests into a single, composite, request with a definite callback |
|
|
1259 | and the ability to cancel the whole request with its subrequests. |
|
|
1260 | |
|
|
1261 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
|
|
1262 | for more info. |
|
|
1263 | |
|
|
1264 | Example: |
|
|
1265 | |
|
|
1266 | my $grp = aio_group sub { |
|
|
1267 | print "all stats done\n"; |
|
|
1268 | }; |
|
|
1269 | |
|
|
1270 | add $grp |
|
|
1271 | (aio_stat ...), |
|
|
1272 | (aio_stat ...), |
|
|
1273 | ...; |
|
|
1274 | |
|
|
1275 | =item aio_nop $callback->() |
|
|
1276 | |
|
|
1277 | This is a special request - it does nothing in itself and is only used for |
|
|
1278 | side effects, such as when you want to add a dummy request to a group so |
|
|
1279 | that finishing the requests in the group depends on executing the given |
|
|
1280 | code. |
|
|
1281 | |
|
|
1282 | While this request does nothing, it still goes through the execution |
|
|
1283 | phase and still requires a worker thread. Thus, the callback will not |
|
|
1284 | be executed immediately but only after other requests in the queue have |
|
|
1285 | entered their execution phase. This can be used to measure request |
|
|
1286 | latency. |
|
|
1287 | |
|
|
1288 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
|
|
1289 | |
|
|
1290 | Mainly used for debugging and benchmarking, this aio request puts one of |
|
|
1291 | the request workers to sleep for the given time. |
|
|
1292 | |
|
|
1293 | While it is theoretically handy to have simple I/O scheduling requests |
|
|
1294 | like sleep and file handle readable/writable, the overhead this creates is |
|
|
1295 | immense (it blocks a thread for a long time) so do not use this function |
|
|
1296 | except to put your application under artificial I/O pressure. |
|
|
1297 | |
260 | =back |
1298 | =back |
261 | |
1299 | |
|
|
1300 | |
|
|
1301 | =head2 IO::AIO::WD - multiple working directories |
|
|
1302 | |
|
|
1303 | Your process only has one current working directory, which is used by all |
|
|
1304 | threads. This makes it hard to use relative paths (some other component |
|
|
1305 | could call C<chdir> at any time, and it is hard to control when the path |
|
|
1306 | will be used by IO::AIO). |
|
|
1307 | |
|
|
1308 | One solution for this is to always use absolute paths. This usually works, |
|
|
1309 | but can be quite slow (the kernel has to walk the whole path on every |
|
|
1310 | access), and can also be a hassle to implement. |
|
|
1311 | |
|
|
1312 | Newer POSIX systems have a number of functions (openat, fdopendir, |
|
|
1313 | futimensat and so on) that make it possible to specify working directories |
|
|
1314 | per operation. |
|
|
1315 | |
|
|
1316 | For portability, and because the clowns who "designed", or shall I write, |
|
|
1317 | perpetrated this new interface were obviously half-drunk, this abstraction |
|
|
1318 | cannot be perfect, though. |
|
|
1319 | |
|
|
1320 | IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD |
|
|
1321 | object. This object stores the canonicalised, absolute version of the |
|
|
1322 | path, and on systems that allow it, also a directory file descriptor. |
|
|
1323 | |
|
|
1324 | Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> |
|
|
1325 | or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD |
|
|
1326 | object and a pathname instead (or the IO::AIO::WD object alone, which |
|
|
1327 | gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the |
|
|
1328 | IO::AIO::WD object is ignored, otherwise the pathname is resolved relative |
|
|
1329 | to that IO::AIO::WD object. |
|
|
1330 | |
|
|
1331 | For example, to get a wd object for F</etc> and then stat F<passwd> |
|
|
1332 | inside, you would write: |
|
|
1333 | |
|
|
1334 | aio_wd "/etc", sub { |
|
|
1335 | my $etcdir = shift; |
|
|
1336 | |
|
|
1337 | # although $etcdir can be undef on error, there is generally no reason |
|
|
1338 | # to check for errors here, as aio_stat will fail with ENOENT |
|
|
1339 | # when $etcdir is undef. |
|
|
1340 | |
|
|
1341 | aio_stat [$etcdir, "passwd"], sub { |
|
|
1342 | # yay |
|
|
1343 | }; |
|
|
1344 | }; |
|
|
1345 | |
|
|
1346 | That C<aio_wd> is a request and not a normal function shows that creating |
|
|
1347 | an IO::AIO::WD object is itself a potentially blocking operation, which is |
|
|
1348 | why it is done asynchronously. |
|
|
1349 | |
|
|
1350 | To stat the directory obtained with C<aio_wd> above, one could write |
|
|
1351 | either of the following three request calls: |
|
|
1352 | |
|
|
1353 | aio_lstat "/etc" , sub { ... # pathname as normal string |
|
|
1354 | aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself) |
|
|
1355 | aio_lstat $wd , sub { ... # shorthand for the previous |
|
|
1356 | |
|
|
1357 | As with normal pathnames, IO::AIO keeps a copy of the working directory |
|
|
1358 | object and the pathname string, so you could write the following without |
|
|
1359 | causing any issues due to C<$path> getting reused: |
|
|
1360 | |
|
|
1361 | my $path = [$wd, undef]; |
|
|
1362 | |
|
|
1363 | for my $name (qw(abc def ghi)) { |
|
|
1364 | $path->[1] = $name; |
|
|
1365 | aio_stat $path, sub { |
|
|
1366 | # ... |
|
|
1367 | }; |
|
|
1368 | } |
|
|
1369 | |
|
|
1370 | There are some caveats: when directories get renamed (or deleted), the |
|
|
1371 | pathname string doesn't change, so will point to the new directory (or |
|
|
1372 | nowhere at all), while the directory fd, if available on the system, |
|
|
1373 | will still point to the original directory. Most functions accepting a |
|
|
1374 | pathname will use the directory fd on newer systems, and the string on |
|
|
1375 | older systems. Some functions (such as realpath) will always rely on the |
|
|
1376 | string form of the pathname. |
|
|
1377 | |
|
|
1378 | So this fucntionality is mainly useful to get some protection against |
|
|
1379 | C<chdir>, to easily get an absolute path out of a relative path for future |
|
|
1380 | reference, and to speed up doing many operations in the same directory |
|
|
1381 | (e.g. when stat'ing all files in a directory). |
|
|
1382 | |
|
|
1383 | The following functions implement this working directory abstraction: |
|
|
1384 | |
|
|
1385 | =over 4 |
|
|
1386 | |
|
|
1387 | =item aio_wd $pathname, $callback->($wd) |
|
|
1388 | |
|
|
1389 | Asynchonously canonicalise the given pathname and convert it to an |
|
|
1390 | IO::AIO::WD object representing it. If possible and supported on the |
|
|
1391 | system, also open a directory fd to speed up pathname resolution relative |
|
|
1392 | to this working directory. |
|
|
1393 | |
|
|
1394 | If something goes wrong, then C<undef> is passwd to the callback instead |
|
|
1395 | of a working directory object and C<$!> is set appropriately. Since |
|
|
1396 | passing C<undef> as working directory component of a pathname fails the |
|
|
1397 | request with C<ENOENT>, there is often no need for error checking in the |
|
|
1398 | C<aio_wd> callback, as future requests using the value will fail in the |
|
|
1399 | expected way. |
|
|
1400 | |
|
|
1401 | If this call isn't available because your OS lacks it or it couldn't be |
|
|
1402 | detected, it will be emulated by calling C<fsync> instead. |
|
|
1403 | |
|
|
1404 | =item IO::AIO::CWD |
|
|
1405 | |
|
|
1406 | This is a compiletime constant (object) that represents the process |
|
|
1407 | current working directory. |
|
|
1408 | |
|
|
1409 | Specifying this object as working directory object for a pathname is as |
|
|
1410 | if the pathname would be specified directly, without a directory object, |
|
|
1411 | e.g., these calls are functionally identical: |
|
|
1412 | |
|
|
1413 | aio_stat "somefile", sub { ... }; |
|
|
1414 | aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; |
|
|
1415 | |
|
|
1416 | =back |
|
|
1417 | |
|
|
1418 | |
|
|
1419 | =head2 IO::AIO::REQ CLASS |
|
|
1420 | |
|
|
1421 | All non-aggregate C<aio_*> functions return an object of this class when |
|
|
1422 | called in non-void context. |
|
|
1423 | |
|
|
1424 | =over 4 |
|
|
1425 | |
|
|
1426 | =item cancel $req |
|
|
1427 | |
|
|
1428 | Cancels the request, if possible. Has the effect of skipping execution |
|
|
1429 | when entering the B<execute> state and skipping calling the callback when |
|
|
1430 | entering the the B<result> state, but will leave the request otherwise |
|
|
1431 | untouched (with the exception of readdir). That means that requests that |
|
|
1432 | currently execute will not be stopped and resources held by the request |
|
|
1433 | will not be freed prematurely. |
|
|
1434 | |
|
|
1435 | =item cb $req $callback->(...) |
|
|
1436 | |
|
|
1437 | Replace (or simply set) the callback registered to the request. |
|
|
1438 | |
|
|
1439 | =back |
|
|
1440 | |
|
|
1441 | =head2 IO::AIO::GRP CLASS |
|
|
1442 | |
|
|
1443 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
|
|
1444 | objects of this class, too. |
|
|
1445 | |
|
|
1446 | A IO::AIO::GRP object is a special request that can contain multiple other |
|
|
1447 | aio requests. |
|
|
1448 | |
|
|
1449 | You create one by calling the C<aio_group> constructing function with a |
|
|
1450 | callback that will be called when all contained requests have entered the |
|
|
1451 | C<done> state: |
|
|
1452 | |
|
|
1453 | my $grp = aio_group sub { |
|
|
1454 | print "all requests are done\n"; |
|
|
1455 | }; |
|
|
1456 | |
|
|
1457 | You add requests by calling the C<add> method with one or more |
|
|
1458 | C<IO::AIO::REQ> objects: |
|
|
1459 | |
|
|
1460 | $grp->add (aio_unlink "..."); |
|
|
1461 | |
|
|
1462 | add $grp aio_stat "...", sub { |
|
|
1463 | $_[0] or return $grp->result ("error"); |
|
|
1464 | |
|
|
1465 | # add another request dynamically, if first succeeded |
|
|
1466 | add $grp aio_open "...", sub { |
|
|
1467 | $grp->result ("ok"); |
|
|
1468 | }; |
|
|
1469 | }; |
|
|
1470 | |
|
|
1471 | This makes it very easy to create composite requests (see the source of |
|
|
1472 | C<aio_move> for an application) that work and feel like simple requests. |
|
|
1473 | |
|
|
1474 | =over 4 |
|
|
1475 | |
|
|
1476 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
|
|
1477 | C<IO::AIO::poll_cb>, just like any other request. |
|
|
1478 | |
|
|
1479 | =item * They can be canceled like any other request. Canceling will cancel not |
|
|
1480 | only the request itself, but also all requests it contains. |
|
|
1481 | |
|
|
1482 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
1483 | |
|
|
1484 | =item * You must not add requests to a group from within the group callback (or |
|
|
1485 | any later time). |
|
|
1486 | |
|
|
1487 | =back |
|
|
1488 | |
|
|
1489 | Their lifetime, simplified, looks like this: when they are empty, they |
|
|
1490 | will finish very quickly. If they contain only requests that are in the |
|
|
1491 | C<done> state, they will also finish. Otherwise they will continue to |
|
|
1492 | exist. |
|
|
1493 | |
|
|
1494 | That means after creating a group you have some time to add requests |
|
|
1495 | (precisely before the callback has been invoked, which is only done within |
|
|
1496 | the C<poll_cb>). And in the callbacks of those requests, you can add |
|
|
1497 | further requests to the group. And only when all those requests have |
|
|
1498 | finished will the the group itself finish. |
|
|
1499 | |
|
|
1500 | =over 4 |
|
|
1501 | |
|
|
1502 | =item add $grp ... |
|
|
1503 | |
|
|
1504 | =item $grp->add (...) |
|
|
1505 | |
|
|
1506 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
|
|
1507 | be added, including other groups, as long as you do not create circular |
|
|
1508 | dependencies. |
|
|
1509 | |
|
|
1510 | Returns all its arguments. |
|
|
1511 | |
|
|
1512 | =item $grp->cancel_subs |
|
|
1513 | |
|
|
1514 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
1515 | itself. Useful when you queued a lot of events but got a result early. |
|
|
1516 | |
|
|
1517 | The group request will finish normally (you cannot add requests to the |
|
|
1518 | group). |
|
|
1519 | |
|
|
1520 | =item $grp->result (...) |
|
|
1521 | |
|
|
1522 | Set the result value(s) that will be passed to the group callback when all |
|
|
1523 | subrequests have finished and set the groups errno to the current value |
|
|
1524 | of errno (just like calling C<errno> without an error number). By default, |
|
|
1525 | no argument will be passed and errno is zero. |
|
|
1526 | |
|
|
1527 | =item $grp->errno ([$errno]) |
|
|
1528 | |
|
|
1529 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
1530 | when the argument is missing. |
|
|
1531 | |
|
|
1532 | Every aio request has an associated errno value that is restored when |
|
|
1533 | the callback is invoked. This method lets you change this value from its |
|
|
1534 | default (0). |
|
|
1535 | |
|
|
1536 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
1537 | before the call to C<result>, or call c<errno> after it. |
|
|
1538 | |
|
|
1539 | =item feed $grp $callback->($grp) |
|
|
1540 | |
|
|
1541 | Sets a feeder/generator on this group: every group can have an attached |
|
|
1542 | generator that generates requests if idle. The idea behind this is that, |
|
|
1543 | although you could just queue as many requests as you want in a group, |
|
|
1544 | this might starve other requests for a potentially long time. For example, |
|
|
1545 | C<aio_scandir> might generate hundreds of thousands of C<aio_stat> |
|
|
1546 | requests, delaying any later requests for a long time. |
|
|
1547 | |
|
|
1548 | To avoid this, and allow incremental generation of requests, you can |
|
|
1549 | instead a group and set a feeder on it that generates those requests. The |
|
|
1550 | feed callback will be called whenever there are few enough (see C<limit>, |
|
|
1551 | below) requests active in the group itself and is expected to queue more |
|
|
1552 | requests. |
|
|
1553 | |
|
|
1554 | The feed callback can queue as many requests as it likes (i.e. C<add> does |
|
|
1555 | not impose any limits). |
|
|
1556 | |
|
|
1557 | If the feed does not queue more requests when called, it will be |
|
|
1558 | automatically removed from the group. |
|
|
1559 | |
|
|
1560 | If the feed limit is C<0> when this method is called, it will be set to |
|
|
1561 | C<2> automatically. |
|
|
1562 | |
|
|
1563 | Example: |
|
|
1564 | |
|
|
1565 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
1566 | |
|
|
1567 | my $grp = aio_group sub { print "finished\n" }; |
|
|
1568 | limit $grp 4; |
|
|
1569 | feed $grp sub { |
|
|
1570 | my $file = pop @files |
|
|
1571 | or return; |
|
|
1572 | |
|
|
1573 | add $grp aio_stat $file, sub { ... }; |
|
|
1574 | }; |
|
|
1575 | |
|
|
1576 | =item limit $grp $num |
|
|
1577 | |
|
|
1578 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
1579 | the group contains less than this many requests. |
|
|
1580 | |
|
|
1581 | Setting the limit to C<0> will pause the feeding process. |
|
|
1582 | |
|
|
1583 | The default value for the limit is C<0>, but note that setting a feeder |
|
|
1584 | automatically bumps it up to C<2>. |
|
|
1585 | |
|
|
1586 | =back |
|
|
1587 | |
262 | =head2 SUPPORT FUNCTIONS |
1588 | =head2 SUPPORT FUNCTIONS |
263 | |
1589 | |
|
|
1590 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
1591 | |
264 | =over 4 |
1592 | =over 4 |
265 | |
1593 | |
266 | =item $fileno = IO::AIO::poll_fileno |
1594 | =item $fileno = IO::AIO::poll_fileno |
267 | |
1595 | |
268 | Return the I<request result pipe file descriptor>. This filehandle must be |
1596 | Return the I<request result pipe file descriptor>. This filehandle must be |
269 | polled for reading by some mechanism outside this module (e.g. Event or |
1597 | polled for reading by some mechanism outside this module (e.g. EV, Glib, |
270 | select, see below or the SYNOPSIS). If the pipe becomes readable you have |
1598 | select and so on, see below or the SYNOPSIS). If the pipe becomes readable |
271 | to call C<poll_cb> to check the results. |
1599 | you have to call C<poll_cb> to check the results. |
272 | |
1600 | |
273 | See C<poll_cb> for an example. |
1601 | See C<poll_cb> for an example. |
274 | |
1602 | |
275 | =item IO::AIO::poll_cb |
1603 | =item IO::AIO::poll_cb |
276 | |
1604 | |
277 | Process all outstanding events on the result pipe. You have to call this |
1605 | Process some outstanding events on the result pipe. You have to call |
278 | regularly. Returns the number of events processed. Returns immediately |
1606 | this regularly. Returns C<0> if all events could be processed (or there |
279 | when no events are outstanding. |
1607 | were no events to process), or C<-1> if it returned earlier for whatever |
|
|
1608 | reason. Returns immediately when no events are outstanding. The amount of |
|
|
1609 | events processed depends on the settings of C<IO::AIO::max_poll_req> and |
|
|
1610 | C<IO::AIO::max_poll_time>. |
|
|
1611 | |
|
|
1612 | If not all requests were processed for whatever reason, the filehandle |
|
|
1613 | will still be ready when C<poll_cb> returns, so normally you don't have to |
|
|
1614 | do anything special to have it called later. |
|
|
1615 | |
|
|
1616 | Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes |
|
|
1617 | ready, it can be beneficial to call this function from loops which submit |
|
|
1618 | a lot of requests, to make sure the results get processed when they become |
|
|
1619 | available and not just when the loop is finished and the event loop takes |
|
|
1620 | over again. This function returns very fast when there are no outstanding |
|
|
1621 | requests. |
280 | |
1622 | |
281 | Example: Install an Event watcher that automatically calls |
1623 | Example: Install an Event watcher that automatically calls |
282 | IO::AIO::poll_cb with high priority: |
1624 | IO::AIO::poll_cb with high priority (more examples can be found in the |
|
|
1625 | SYNOPSIS section, at the top of this document): |
283 | |
1626 | |
284 | Event->io (fd => IO::AIO::poll_fileno, |
1627 | Event->io (fd => IO::AIO::poll_fileno, |
285 | poll => 'r', async => 1, |
1628 | poll => 'r', async => 1, |
286 | cb => \&IO::AIO::poll_cb); |
1629 | cb => \&IO::AIO::poll_cb); |
287 | |
1630 | |
288 | =item IO::AIO::poll_wait |
1631 | =item IO::AIO::poll_wait |
289 | |
1632 | |
|
|
1633 | If there are any outstanding requests and none of them in the result |
290 | Wait till the result filehandle becomes ready for reading (simply does a |
1634 | phase, wait till the result filehandle becomes ready for reading (simply |
291 | C<select> on the filehandle. This is useful if you want to synchronously wait |
1635 | does a C<select> on the filehandle. This is useful if you want to |
292 | for some requests to finish). |
1636 | synchronously wait for some requests to finish). |
293 | |
1637 | |
294 | See C<nreqs> for an example. |
1638 | See C<nreqs> for an example. |
295 | |
1639 | |
|
|
1640 | =item IO::AIO::poll |
|
|
1641 | |
|
|
1642 | Waits until some requests have been handled. |
|
|
1643 | |
|
|
1644 | Returns the number of requests processed, but is otherwise strictly |
|
|
1645 | equivalent to: |
|
|
1646 | |
|
|
1647 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1648 | |
296 | =item IO::AIO::nreqs |
1649 | =item IO::AIO::flush |
297 | |
1650 | |
298 | Returns the number of requests currently outstanding (i.e. for which their |
1651 | Wait till all outstanding AIO requests have been handled. |
299 | callback has not been invoked yet). |
|
|
300 | |
1652 | |
301 | Example: wait till there are no outstanding requests anymore: |
1653 | Strictly equivalent to: |
302 | |
1654 | |
303 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1655 | IO::AIO::poll_wait, IO::AIO::poll_cb |
304 | while IO::AIO::nreqs; |
1656 | while IO::AIO::nreqs; |
305 | |
1657 | |
306 | =item IO::AIO::flush |
1658 | =item IO::AIO::max_poll_reqs $nreqs |
307 | |
1659 | |
308 | Wait till all outstanding AIO requests have been handled. |
1660 | =item IO::AIO::max_poll_time $seconds |
309 | |
1661 | |
310 | Strictly equivalent to: |
1662 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
1663 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
1664 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
1665 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
1666 | of time C<poll_cb> is allowed to use). |
311 | |
1667 | |
312 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1668 | Setting C<max_poll_time> to a non-zero value creates an overhead of one |
313 | while IO::AIO::nreqs; |
1669 | syscall per request processed, which is not normally a problem unless your |
|
|
1670 | callbacks are really really fast or your OS is really really slow (I am |
|
|
1671 | not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead. |
314 | |
1672 | |
315 | =item IO::AIO::poll |
1673 | Setting these is useful if you want to ensure some level of |
|
|
1674 | interactiveness when perl is not fast enough to process all requests in |
|
|
1675 | time. |
316 | |
1676 | |
317 | Waits until some requests have been handled. |
1677 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
318 | |
1678 | |
319 | Strictly equivalent to: |
1679 | Example: Install an Event watcher that automatically calls |
|
|
1680 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
|
|
1681 | program get the CPU sometimes even under high AIO load. |
320 | |
1682 | |
321 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1683 | # try not to spend much more than 0.1s in poll_cb |
322 | if IO::AIO::nreqs; |
1684 | IO::AIO::max_poll_time 0.1; |
|
|
1685 | |
|
|
1686 | # use a low priority so other tasks have priority |
|
|
1687 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1688 | poll => 'r', nice => 1, |
|
|
1689 | cb => &IO::AIO::poll_cb); |
|
|
1690 | |
|
|
1691 | =back |
|
|
1692 | |
|
|
1693 | =head3 CONTROLLING THE NUMBER OF THREADS |
|
|
1694 | |
|
|
1695 | =over |
323 | |
1696 | |
324 | =item IO::AIO::min_parallel $nthreads |
1697 | =item IO::AIO::min_parallel $nthreads |
325 | |
1698 | |
326 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
1699 | Set the minimum number of AIO threads to C<$nthreads>. The current |
327 | is C<4>, which means four asynchronous operations can be done at one time |
1700 | default is C<8>, which means eight asynchronous operations can execute |
328 | (the number of outstanding operations, however, is unlimited). |
1701 | concurrently at any one time (the number of outstanding requests, |
|
|
1702 | however, is unlimited). |
329 | |
1703 | |
330 | IO::AIO starts threads only on demand, when an AIO request is queued and |
1704 | IO::AIO starts threads only on demand, when an AIO request is queued and |
331 | no free thread exists. |
1705 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
1706 | create demand for a hundred threads, even if it turns out that everything |
|
|
1707 | is in the cache and could have been processed faster by a single thread. |
332 | |
1708 | |
333 | It is recommended to keep the number of threads low, as some Linux |
1709 | It is recommended to keep the number of threads relatively low, as some |
334 | kernel versions will scale negatively with the number of threads (higher |
1710 | Linux kernel versions will scale negatively with the number of threads |
335 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
1711 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
336 | threads should be fine. |
1712 | versions, 4-32 threads should be fine. |
337 | |
1713 | |
338 | Under most circumstances you don't need to call this function, as the |
1714 | Under most circumstances you don't need to call this function, as the |
339 | module selects a default that is suitable for low to moderate load. |
1715 | module selects a default that is suitable for low to moderate load. |
340 | |
1716 | |
341 | =item IO::AIO::max_parallel $nthreads |
1717 | =item IO::AIO::max_parallel $nthreads |
… | |
… | |
350 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1726 | This module automatically runs C<max_parallel 0> at program end, to ensure |
351 | that all threads are killed and that there are no outstanding requests. |
1727 | that all threads are killed and that there are no outstanding requests. |
352 | |
1728 | |
353 | Under normal circumstances you don't need to call this function. |
1729 | Under normal circumstances you don't need to call this function. |
354 | |
1730 | |
|
|
1731 | =item IO::AIO::max_idle $nthreads |
|
|
1732 | |
|
|
1733 | Limit the number of threads (default: 4) that are allowed to idle |
|
|
1734 | (i.e., threads that did not get a request to process within the idle |
|
|
1735 | timeout (default: 10 seconds). That means if a thread becomes idle while |
|
|
1736 | C<$nthreads> other threads are also idle, it will free its resources and |
|
|
1737 | exit. |
|
|
1738 | |
|
|
1739 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1740 | to allow for extremely high load situations, but want to free resources |
|
|
1741 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1742 | |
|
|
1743 | The default is probably ok in most situations, especially if thread |
|
|
1744 | creation is fast. If thread creation is very slow on your system you might |
|
|
1745 | want to use larger values. |
|
|
1746 | |
|
|
1747 | =item IO::AIO::idle_timeout $seconds |
|
|
1748 | |
|
|
1749 | Sets the minimum idle timeout (default 10) after which worker threads are |
|
|
1750 | allowed to exit. SEe C<IO::AIO::max_idle>. |
|
|
1751 | |
355 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
1752 | =item IO::AIO::max_outstanding $maxreqs |
356 | |
1753 | |
357 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1754 | Sets the maximum number of outstanding requests to C<$nreqs>. If |
358 | try to queue up more than this number of requests, the caller will block until |
1755 | you do queue up more than this number of requests, the next call to |
359 | some requests have been handled. |
1756 | C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as |
|
|
1757 | C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no |
|
|
1758 | longer exceeded. |
360 | |
1759 | |
361 | The default is very large, so normally there is no practical limit. If you |
1760 | In other words, this setting does not enforce a queue limit, but can be |
362 | queue up many requests in a loop it often improves speed if you set |
1761 | used to make poll functions block if the limit is exceeded. |
363 | this to a relatively low number, such as C<100>. |
|
|
364 | |
1762 | |
365 | Under normal circumstances you don't need to call this function. |
1763 | This is a very bad function to use in interactive programs because it |
|
|
1764 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1765 | use an C<aio_group> together with a feed callback. |
|
|
1766 | |
|
|
1767 | It's main use is in scripts without an event loop - when you want to stat |
|
|
1768 | a lot of files, you can write somehting like this: |
|
|
1769 | |
|
|
1770 | IO::AIO::max_outstanding 32; |
|
|
1771 | |
|
|
1772 | for my $path (...) { |
|
|
1773 | aio_stat $path , ...; |
|
|
1774 | IO::AIO::poll_cb; |
|
|
1775 | } |
|
|
1776 | |
|
|
1777 | IO::AIO::flush; |
|
|
1778 | |
|
|
1779 | The call to C<poll_cb> inside the loop will normally return instantly, but |
|
|
1780 | as soon as more thna C<32> reqeusts are in-flight, it will block until |
|
|
1781 | some requests have been handled. This keeps the loop from pushing a large |
|
|
1782 | number of C<aio_stat> requests onto the queue. |
|
|
1783 | |
|
|
1784 | The default value for C<max_outstanding> is very large, so there is no |
|
|
1785 | practical limit on the number of outstanding requests. |
366 | |
1786 | |
367 | =back |
1787 | =back |
368 | |
1788 | |
|
|
1789 | =head3 STATISTICAL INFORMATION |
|
|
1790 | |
|
|
1791 | =over |
|
|
1792 | |
|
|
1793 | =item IO::AIO::nreqs |
|
|
1794 | |
|
|
1795 | Returns the number of requests currently in the ready, execute or pending |
|
|
1796 | states (i.e. for which their callback has not been invoked yet). |
|
|
1797 | |
|
|
1798 | Example: wait till there are no outstanding requests anymore: |
|
|
1799 | |
|
|
1800 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1801 | while IO::AIO::nreqs; |
|
|
1802 | |
|
|
1803 | =item IO::AIO::nready |
|
|
1804 | |
|
|
1805 | Returns the number of requests currently in the ready state (not yet |
|
|
1806 | executed). |
|
|
1807 | |
|
|
1808 | =item IO::AIO::npending |
|
|
1809 | |
|
|
1810 | Returns the number of requests currently in the pending state (executed, |
|
|
1811 | but not yet processed by poll_cb). |
|
|
1812 | |
|
|
1813 | =back |
|
|
1814 | |
|
|
1815 | =head3 MISCELLANEOUS FUNCTIONS |
|
|
1816 | |
|
|
1817 | IO::AIO implements some functions that might be useful, but are not |
|
|
1818 | asynchronous. |
|
|
1819 | |
|
|
1820 | =over 4 |
|
|
1821 | |
|
|
1822 | =item IO::AIO::sendfile $ofh, $ifh, $offset, $count |
|
|
1823 | |
|
|
1824 | Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, |
|
|
1825 | but is blocking (this makes most sense if you know the input data is |
|
|
1826 | likely cached already and the output filehandle is set to non-blocking |
|
|
1827 | operations). |
|
|
1828 | |
|
|
1829 | Returns the number of bytes copied, or C<-1> on error. |
|
|
1830 | |
|
|
1831 | =item IO::AIO::fadvise $fh, $offset, $len, $advice |
|
|
1832 | |
|
|
1833 | Simply calls the C<posix_fadvise> function (see its |
|
|
1834 | manpage for details). The following advice constants are |
|
|
1835 | available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, |
|
|
1836 | C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, |
|
|
1837 | C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. |
|
|
1838 | |
|
|
1839 | On systems that do not implement C<posix_fadvise>, this function returns |
|
|
1840 | ENOSYS, otherwise the return value of C<posix_fadvise>. |
|
|
1841 | |
|
|
1842 | =item IO::AIO::madvise $scalar, $offset, $len, $advice |
|
|
1843 | |
|
|
1844 | Simply calls the C<posix_madvise> function (see its |
|
|
1845 | manpage for details). The following advice constants are |
|
|
1846 | available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, |
|
|
1847 | C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. |
|
|
1848 | |
|
|
1849 | On systems that do not implement C<posix_madvise>, this function returns |
|
|
1850 | ENOSYS, otherwise the return value of C<posix_madvise>. |
|
|
1851 | |
|
|
1852 | =item IO::AIO::mprotect $scalar, $offset, $len, $protect |
|
|
1853 | |
|
|
1854 | Simply calls the C<mprotect> function on the preferably AIO::mmap'ed |
|
|
1855 | $scalar (see its manpage for details). The following protect |
|
|
1856 | constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, |
|
|
1857 | C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. |
|
|
1858 | |
|
|
1859 | On systems that do not implement C<mprotect>, this function returns |
|
|
1860 | ENOSYS, otherwise the return value of C<mprotect>. |
|
|
1861 | |
|
|
1862 | =item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] |
|
|
1863 | |
|
|
1864 | Memory-maps a file (or anonymous memory range) and attaches it to the |
|
|
1865 | given C<$scalar>, which will act like a string scalar. |
|
|
1866 | |
|
|
1867 | The only operations allowed on the scalar are C<substr>/C<vec> that don't |
|
|
1868 | change the string length, and most read-only operations such as copying it |
|
|
1869 | or searching it with regexes and so on. |
|
|
1870 | |
|
|
1871 | Anything else is unsafe and will, at best, result in memory leaks. |
|
|
1872 | |
|
|
1873 | The memory map associated with the C<$scalar> is automatically removed |
|
|
1874 | when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or |
|
|
1875 | C<IO::AIO::munmap> functions are called. |
|
|
1876 | |
|
|
1877 | This calls the C<mmap>(2) function internally. See your system's manual |
|
|
1878 | page for details on the C<$length>, C<$prot> and C<$flags> parameters. |
|
|
1879 | |
|
|
1880 | The C<$length> must be larger than zero and smaller than the actual |
|
|
1881 | filesize. |
|
|
1882 | |
|
|
1883 | C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, |
|
|
1884 | C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, |
|
|
1885 | |
|
|
1886 | C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or |
|
|
1887 | C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when |
|
|
1888 | not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> |
|
|
1889 | (which is set to C<MAP_ANON> if your system only provides this |
|
|
1890 | constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, |
|
|
1891 | C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or |
|
|
1892 | C<IO::AIO::MAP_NONBLOCK> |
|
|
1893 | |
|
|
1894 | If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. |
|
|
1895 | |
|
|
1896 | C<$offset> is the offset from the start of the file - it generally must be |
|
|
1897 | a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. |
|
|
1898 | |
|
|
1899 | Example: |
|
|
1900 | |
|
|
1901 | use Digest::MD5; |
|
|
1902 | use IO::AIO; |
|
|
1903 | |
|
|
1904 | open my $fh, "<verybigfile" |
|
|
1905 | or die "$!"; |
|
|
1906 | |
|
|
1907 | IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh |
|
|
1908 | or die "verybigfile: $!"; |
|
|
1909 | |
|
|
1910 | my $fast_md5 = md5 $data; |
|
|
1911 | |
|
|
1912 | =item IO::AIO::munmap $scalar |
|
|
1913 | |
|
|
1914 | Removes a previous mmap and undefines the C<$scalar>. |
|
|
1915 | |
|
|
1916 | =item IO::AIO::munlock $scalar, $offset = 0, $length = undef |
|
|
1917 | |
|
|
1918 | Calls the C<munlock> function, undoing the effects of a previous |
|
|
1919 | C<aio_mlock> call (see its description for details). |
|
|
1920 | |
|
|
1921 | =item IO::AIO::munlockall |
|
|
1922 | |
|
|
1923 | Calls the C<munlockall> function. |
|
|
1924 | |
|
|
1925 | On systems that do not implement C<munlockall>, this function returns |
|
|
1926 | ENOSYS, otherwise the return value of C<munlockall>. |
|
|
1927 | |
|
|
1928 | =back |
|
|
1929 | |
369 | =cut |
1930 | =cut |
370 | |
1931 | |
371 | # support function to convert a fd into a perl filehandle |
|
|
372 | sub _fd2fh { |
|
|
373 | return undef if $_[0] < 0; |
|
|
374 | |
|
|
375 | # try to generate nice filehandles |
|
|
376 | my $sym = "IO::AIO::fd#$_[0]"; |
|
|
377 | local *$sym; |
|
|
378 | |
|
|
379 | open *$sym, "+<&=$_[0]" # usually works under any unix |
|
|
380 | or open *$sym, "<&=$_[0]" # cygwin needs this |
|
|
381 | or open *$sym, ">&=$_[0]" # or this |
|
|
382 | or return undef; |
|
|
383 | |
|
|
384 | *$sym |
|
|
385 | } |
|
|
386 | |
|
|
387 | min_parallel 4; |
1932 | min_parallel 8; |
388 | |
1933 | |
389 | END { |
1934 | END { flush } |
390 | max_parallel 0; |
|
|
391 | } |
|
|
392 | |
1935 | |
393 | 1; |
1936 | 1; |
394 | |
1937 | |
|
|
1938 | =head1 EVENT LOOP INTEGRATION |
|
|
1939 | |
|
|
1940 | It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO |
|
|
1941 | automatically into many event loops: |
|
|
1942 | |
|
|
1943 | # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) |
|
|
1944 | use AnyEvent::AIO; |
|
|
1945 | |
|
|
1946 | You can also integrate IO::AIO manually into many event loops, here are |
|
|
1947 | some examples of how to do this: |
|
|
1948 | |
|
|
1949 | # EV integration |
|
|
1950 | my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; |
|
|
1951 | |
|
|
1952 | # Event integration |
|
|
1953 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
1954 | poll => 'r', |
|
|
1955 | cb => \&IO::AIO::poll_cb); |
|
|
1956 | |
|
|
1957 | # Glib/Gtk2 integration |
|
|
1958 | add_watch Glib::IO IO::AIO::poll_fileno, |
|
|
1959 | in => sub { IO::AIO::poll_cb; 1 }; |
|
|
1960 | |
|
|
1961 | # Tk integration |
|
|
1962 | Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", |
|
|
1963 | readable => \&IO::AIO::poll_cb); |
|
|
1964 | |
|
|
1965 | # Danga::Socket integration |
|
|
1966 | Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => |
|
|
1967 | \&IO::AIO::poll_cb); |
|
|
1968 | |
395 | =head2 FORK BEHAVIOUR |
1969 | =head2 FORK BEHAVIOUR |
396 | |
1970 | |
397 | Before the fork, IO::AIO enters a quiescent state where no requests |
1971 | Usage of pthreads in a program changes the semantics of fork |
398 | can be added in other threads and no results will be processed. After |
1972 | considerably. Specifically, only async-safe functions can be called after |
399 | the fork the parent simply leaves the quiescent state and continues |
1973 | fork. Perl doesn't know about this, so in general, you cannot call fork |
400 | request/result processing, while the child clears the request/result |
1974 | with defined behaviour in perl if pthreads are involved. IO::AIO uses |
401 | queue (so the requests started before the fork will only be handled in |
1975 | pthreads, so this applies, but many other extensions and (for inexplicable |
402 | the parent). Threats will be started on demand until the limit ste in the |
1976 | reasons) perl itself often is linked against pthreads, so this limitation |
403 | parent process has been reached again. |
1977 | applies to quite a lot of perls. |
|
|
1978 | |
|
|
1979 | This module no longer tries to fight your OS, or POSIX. That means IO::AIO |
|
|
1980 | only works in the process that loaded it. Forking is fully supported, but |
|
|
1981 | using IO::AIO in the child is not. |
|
|
1982 | |
|
|
1983 | You might get around by not I<using> IO::AIO before (or after) |
|
|
1984 | forking. You could also try to call the L<IO::AIO::reinit> function in the |
|
|
1985 | child: |
|
|
1986 | |
|
|
1987 | =over 4 |
|
|
1988 | |
|
|
1989 | =item IO::AIO::reinit |
|
|
1990 | |
|
|
1991 | Abandons all current requests and I/O threads and simply reinitialises all |
|
|
1992 | data structures. This is not an operation supported by any standards, but |
|
|
1993 | happens to work on GNU/Linux and some newer BSD systems. |
|
|
1994 | |
|
|
1995 | The only reasonable use for this function is to call it after forking, if |
|
|
1996 | C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in |
|
|
1997 | the process will result in undefined behaviour. Calling it at any time |
|
|
1998 | will also result in any undefined (by POSIX) behaviour. |
|
|
1999 | |
|
|
2000 | =back |
|
|
2001 | |
|
|
2002 | =head2 MEMORY USAGE |
|
|
2003 | |
|
|
2004 | Per-request usage: |
|
|
2005 | |
|
|
2006 | Each aio request uses - depending on your architecture - around 100-200 |
|
|
2007 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
|
|
2008 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
|
|
2009 | scalars and other data passed into aio requests will also be locked and |
|
|
2010 | will consume memory till the request has entered the done state. |
|
|
2011 | |
|
|
2012 | This is not awfully much, so queuing lots of requests is not usually a |
|
|
2013 | problem. |
|
|
2014 | |
|
|
2015 | Per-thread usage: |
|
|
2016 | |
|
|
2017 | In the execution phase, some aio requests require more memory for |
|
|
2018 | temporary buffers, and each thread requires a stack and other data |
|
|
2019 | structures (usually around 16k-128k, depending on the OS). |
|
|
2020 | |
|
|
2021 | =head1 KNOWN BUGS |
|
|
2022 | |
|
|
2023 | Known bugs will be fixed in the next release. |
404 | |
2024 | |
405 | =head1 SEE ALSO |
2025 | =head1 SEE ALSO |
406 | |
2026 | |
407 | L<Coro>, L<Linux::AIO>. |
2027 | L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a |
|
|
2028 | more natural syntax. |
408 | |
2029 | |
409 | =head1 AUTHOR |
2030 | =head1 AUTHOR |
410 | |
2031 | |
411 | Marc Lehmann <schmorp@schmorp.de> |
2032 | Marc Lehmann <schmorp@schmorp.de> |
412 | http://home.schmorp.de/ |
2033 | http://home.schmorp.de/ |