… | |
… | |
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", O_RDONLY, 0, sub { |
10 | my ($fh) = @_; |
10 | my $fh = shift |
|
|
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 | |
… | |
… | |
51 | =head1 DESCRIPTION |
52 | =head1 DESCRIPTION |
52 | |
53 | |
53 | This module implements asynchronous I/O using whatever means your |
54 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. |
55 | operating system supports. |
55 | |
56 | |
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57 | Asynchronous means that operations that can normally block your program |
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58 | (e.g. reading from disk) will be done asynchronously: the operation |
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59 | will still block, but you can do something else in the meantime. This |
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60 | is extremely useful for programs that need to stay interactive even |
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61 | when doing heavy I/O (GUI programs, high performance network servers |
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62 | etc.), but can also be used to easily do operations in parallel that are |
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63 | normally done sequentially, e.g. stat'ing many files, which is much faster |
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64 | on a RAID volume or over NFS when you do a number of stat operations |
|
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65 | concurrently. |
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66 | |
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67 | While most of this works on all types of file descriptors (for example |
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68 | sockets), using these functions on file descriptors that support |
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69 | nonblocking operation (again, sockets, pipes etc.) is very inefficient or |
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70 | might not work (aio_read fails on sockets/pipes/fifos). Use an event loop |
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71 | for that (such as the L<Event|Event> module): IO::AIO will naturally fit |
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72 | into such an event loop itself. |
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73 | |
56 | Currently, a number of threads are started that execute your read/writes |
74 | In this version, a number of threads are started that execute your |
57 | and signal their completion. You don't need thread support in perl, and |
75 | requests and signal their completion. You don't need thread support |
58 | the threads created by this module will not be visible to perl. In the |
76 | in perl, and the threads created by this module will not be visible |
59 | future, this module might make use of the native aio functions available |
77 | to perl. In the future, this module might make use of the native aio |
60 | on many operating systems. However, they are often not well-supported |
78 | functions available on many operating systems. However, they are often |
61 | (Linux doesn't allow them on normal files currently, for example), |
79 | not well-supported or restricted (GNU/Linux doesn't allow them on normal |
62 | and they would only support aio_read and aio_write, so the remaining |
80 | files currently, for example), and they would only support aio_read and |
63 | functionality would have to be implemented using threads anyway. |
81 | aio_write, so the remaining functionality would have to be implemented |
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82 | using threads anyway. |
64 | |
83 | |
65 | Although the module will work with in the presence of other threads, |
84 | Although the module will work with in the presence of other (Perl-) |
66 | it is currently not reentrant in any way, so use appropriate locking |
85 | threads, it is currently not reentrant in any way, so use appropriate |
67 | yourself, always call C<poll_cb> from within the same thread, or never |
86 | locking yourself, always call C<poll_cb> from within the same thread, or |
68 | call C<poll_cb> (or other C<aio_> functions) recursively. |
87 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
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88 | |
|
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89 | =head2 EXAMPLE |
|
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90 | |
|
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91 | This is a simple example that uses the Event module and loads |
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92 | F</etc/passwd> asynchronously: |
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93 | |
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94 | use Fcntl; |
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95 | use Event; |
|
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96 | use IO::AIO; |
|
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97 | |
|
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98 | # register the IO::AIO callback with Event |
|
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99 | Event->io (fd => IO::AIO::poll_fileno, |
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100 | poll => 'r', |
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101 | cb => \&IO::AIO::poll_cb); |
|
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102 | |
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103 | # queue the request to open /etc/passwd |
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104 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
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105 | my $fh = shift |
|
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106 | or die "error while opening: $!"; |
|
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107 | |
|
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108 | # stat'ing filehandles is generally non-blocking |
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109 | my $size = -s $fh; |
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110 | |
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111 | # queue a request to read the file |
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112 | my $contents; |
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113 | aio_read $fh, 0, $size, $contents, 0, sub { |
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114 | $_[0] == $size |
|
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115 | or die "short read: $!"; |
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116 | |
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117 | close $fh; |
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118 | |
|
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119 | # file contents now in $contents |
|
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120 | print $contents; |
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121 | |
|
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122 | # exit event loop and program |
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123 | Event::unloop; |
|
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124 | }; |
|
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125 | }; |
|
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126 | |
|
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127 | # possibly queue up other requests, or open GUI windows, |
|
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128 | # check for sockets etc. etc. |
|
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129 | |
|
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130 | # process events as long as there are some: |
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131 | Event::loop; |
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132 | |
|
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133 | =head1 REQUEST ANATOMY AND LIFETIME |
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134 | |
|
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135 | Every C<aio_*> function creates a request. which is a C data structure not |
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136 | directly visible to Perl. |
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137 | |
|
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138 | If called in non-void context, every request function returns a Perl |
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139 | object representing the request. In void context, nothing is returned, |
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140 | which saves a bit of memory. |
|
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141 | |
|
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142 | The perl object is a fairly standard ref-to-hash object. The hash contents |
|
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143 | are not used by IO::AIO so you are free to store anything you like in it. |
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144 | |
|
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145 | During their existance, aio requests travel through the following states, |
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146 | in order: |
|
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147 | |
|
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148 | =over 4 |
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149 | |
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150 | =item ready |
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151 | |
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152 | Immediately after a request is created it is put into the ready state, |
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153 | waiting for a thread to execute it. |
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154 | |
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155 | =item execute |
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156 | |
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157 | A thread has accepted the request for processing and is currently |
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158 | executing it (e.g. blocking in read). |
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159 | |
|
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160 | =item pending |
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161 | |
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162 | The request has been executed and is waiting for result processing. |
|
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163 | |
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164 | While request submission and execution is fully asynchronous, result |
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165 | processing is not and relies on the perl interpreter calling C<poll_cb> |
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166 | (or another function with the same effect). |
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167 | |
|
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168 | =item result |
|
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169 | |
|
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170 | The request results are processed synchronously by C<poll_cb>. |
|
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171 | |
|
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172 | The C<poll_cb> function will process all outstanding aio requests by |
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173 | calling their callbacks, freeing memory associated with them and managing |
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174 | any groups they are contained in. |
|
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175 | |
|
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176 | =item done |
|
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177 | |
|
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178 | Request has reached the end of its lifetime and holds no resources anymore |
|
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179 | (except possibly for the Perl object, but its connection to the actual |
|
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180 | aio request is severed and calling its methods will either do nothing or |
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181 | result in a runtime error). |
|
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182 | |
|
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183 | =back |
69 | |
184 | |
70 | =cut |
185 | =cut |
71 | |
186 | |
72 | package IO::AIO; |
187 | package IO::AIO; |
73 | |
188 | |
… | |
… | |
75 | use strict 'vars'; |
190 | use strict 'vars'; |
76 | |
191 | |
77 | use base 'Exporter'; |
192 | use base 'Exporter'; |
78 | |
193 | |
79 | BEGIN { |
194 | BEGIN { |
80 | our $VERSION = '2.0'; |
195 | our $VERSION = '2.3'; |
81 | |
196 | |
82 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
197 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
83 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
198 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
84 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
199 | aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link |
85 | aio_group aio_nop); |
200 | aio_move aio_copy aio_group aio_nop aio_mknod); |
86 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri)); |
201 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); |
87 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
202 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
88 | min_parallel max_parallel max_outstanding nreqs); |
203 | min_parallel max_parallel max_idle |
|
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204 | nreqs nready npending nthreads |
|
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205 | max_poll_time max_poll_reqs); |
89 | |
206 | |
90 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
207 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
91 | |
208 | |
92 | require XSLoader; |
209 | require XSLoader; |
93 | XSLoader::load ("IO::AIO", $VERSION); |
210 | XSLoader::load ("IO::AIO", $VERSION); |
94 | } |
211 | } |
95 | |
212 | |
96 | =head1 FUNCTIONS |
213 | =head1 FUNCTIONS |
97 | |
214 | |
98 | =head2 AIO FUNCTIONS |
215 | =head2 AIO REQUEST FUNCTIONS |
99 | |
216 | |
100 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
217 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
101 | with the same name (sans C<aio_>). The arguments are similar or identical, |
218 | with the same name (sans C<aio_>). The arguments are similar or identical, |
102 | and they all accept an additional (and optional) C<$callback> argument |
219 | and they all accept an additional (and optional) C<$callback> argument |
103 | which must be a code reference. This code reference will get called with |
220 | which must be a code reference. This code reference will get called with |
… | |
… | |
106 | syscall has been executed asynchronously. |
223 | syscall has been executed asynchronously. |
107 | |
224 | |
108 | All functions expecting a filehandle keep a copy of the filehandle |
225 | All functions expecting a filehandle keep a copy of the filehandle |
109 | internally until the request has finished. |
226 | internally until the request has finished. |
110 | |
227 | |
111 | All requests return objects of type L<IO::AIO::REQ> that allow further |
228 | All functions return request objects of type L<IO::AIO::REQ> that allow |
112 | manipulation of those requests while they are in-flight. |
229 | further manipulation of those requests while they are in-flight. |
113 | |
230 | |
114 | The pathnames you pass to these routines I<must> be absolute and |
231 | The pathnames you pass to these routines I<must> be absolute and |
115 | encoded in byte form. The reason for the former is that at the time the |
232 | encoded as octets. The reason for the former is that at the time the |
116 | request is being executed, the current working directory could have |
233 | request is being executed, the current working directory could have |
117 | changed. Alternatively, you can make sure that you never change the |
234 | changed. Alternatively, you can make sure that you never change the |
118 | current working directory. |
235 | current working directory anywhere in the program and then use relative |
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236 | paths. |
119 | |
237 | |
120 | To encode pathnames to byte form, either make sure you either: a) |
238 | To encode pathnames as octets, either make sure you either: a) always pass |
121 | always pass in filenames you got from outside (command line, readdir |
239 | in filenames you got from outside (command line, readdir etc.) without |
122 | etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
240 | tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode |
123 | your pathnames to the locale (or other) encoding in effect in the user |
241 | your pathnames to the locale (or other) encoding in effect in the user |
124 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
242 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
125 | use something else. |
243 | use something else to ensure your scalar has the correct contents. |
|
|
244 | |
|
|
245 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
|
|
246 | handles correctly wether it is set or not. |
126 | |
247 | |
127 | =over 4 |
248 | =over 4 |
128 | |
249 | |
129 | =item aioreq_pri $pri |
250 | =item $prev_pri = aioreq_pri [$pri] |
130 | |
251 | |
131 | Sets the priority for the next aio request. The default priority |
252 | Returns the priority value that would be used for the next request and, if |
|
|
253 | C<$pri> is given, sets the priority for the next aio request. |
|
|
254 | |
132 | is C<0>, the minimum and maximum priorities are C<-4> and C<4>, |
255 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
133 | respectively. Requests with higher priority will be serviced first. |
256 | and C<4>, respectively. Requests with higher priority will be serviced |
|
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257 | first. |
134 | |
258 | |
135 | The priority will be reset to C<0> after each call to one of the C<aio_> |
259 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
136 | functions. |
260 | functions. |
|
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261 | |
|
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262 | Example: open a file with low priority, then read something from it with |
|
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263 | higher priority so the read request is serviced before other low priority |
|
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264 | open requests (potentially spamming the cache): |
|
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265 | |
|
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266 | aioreq_pri -3; |
|
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267 | aio_open ..., sub { |
|
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268 | return unless $_[0]; |
|
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269 | |
|
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270 | aioreq_pri -2; |
|
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271 | aio_read $_[0], ..., sub { |
|
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272 | ... |
|
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273 | }; |
|
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274 | }; |
|
|
275 | |
|
|
276 | =item aioreq_nice $pri_adjust |
|
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277 | |
|
|
278 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
|
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279 | priority, so the effect is cumulative. |
137 | |
280 | |
138 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
281 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
139 | |
282 | |
140 | Asynchronously open or create a file and call the callback with a newly |
283 | Asynchronously open or create a file and call the callback with a newly |
141 | created filehandle for the file. |
284 | created filehandle for the file. |
… | |
… | |
192 | aio_read $fh, 7, 15, $buffer, 0, sub { |
335 | aio_read $fh, 7, 15, $buffer, 0, sub { |
193 | $_[0] > 0 or die "read error: $!"; |
336 | $_[0] > 0 or die "read error: $!"; |
194 | print "read $_[0] bytes: <$buffer>\n"; |
337 | print "read $_[0] bytes: <$buffer>\n"; |
195 | }; |
338 | }; |
196 | |
339 | |
197 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
198 | |
|
|
199 | [EXPERIMENTAL due to internal aio_group use] |
|
|
200 | |
|
|
201 | Try to move the I<file> (directories not supported as either source or |
|
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202 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
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203 | the C<0> (error) or C<-1> ok. |
|
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204 | |
|
|
205 | This is a composite request that tries to rename(2) the file first. If |
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206 | rename files with C<EXDEV>, it creates the destination file with mode 0200 |
|
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207 | and copies the contents of the source file into it using C<aio_sendfile>, |
|
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208 | followed by restoring atime, mtime, access mode and uid/gid, in that |
|
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209 | order, and unlinking the C<$srcpath>. |
|
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210 | |
|
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211 | If an error occurs, the partial destination file will be unlinked, if |
|
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212 | possible, except when setting atime, mtime, access mode and uid/gid, where |
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213 | errors are being ignored. |
|
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214 | |
|
|
215 | =cut |
|
|
216 | |
|
|
217 | sub aio_move($$$) { |
|
|
218 | my ($src, $dst, $cb) = @_; |
|
|
219 | |
|
|
220 | my $grp = aio_group $cb; |
|
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221 | |
|
|
222 | add $grp aio_rename $src, $dst, sub { |
|
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223 | if ($_[0] && $! == EXDEV) { |
|
|
224 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
225 | if (my $src_fh = $_[0]) { |
|
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226 | my @stat = stat $src_fh; |
|
|
227 | |
|
|
228 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
|
|
229 | if (my $dst_fh = $_[0]) { |
|
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230 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
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231 | close $src_fh; |
|
|
232 | |
|
|
233 | if ($_[0] == $stat[7]) { |
|
|
234 | utime $stat[8], $stat[9], $dst; |
|
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235 | chmod $stat[2] & 07777, $dst_fh; |
|
|
236 | chown $stat[4], $stat[5], $dst_fh; |
|
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237 | close $dst_fh; |
|
|
238 | |
|
|
239 | add $grp aio_unlink $src, sub { |
|
|
240 | $grp->result ($_[0]); |
|
|
241 | }; |
|
|
242 | } else { |
|
|
243 | my $errno = $!; |
|
|
244 | add $grp aio_unlink $dst, sub { |
|
|
245 | $! = $errno; |
|
|
246 | $grp->result (-1); |
|
|
247 | }; |
|
|
248 | } |
|
|
249 | }; |
|
|
250 | } else { |
|
|
251 | $grp->result (-1); |
|
|
252 | } |
|
|
253 | }, |
|
|
254 | |
|
|
255 | } else { |
|
|
256 | $grp->result (-1); |
|
|
257 | } |
|
|
258 | }; |
|
|
259 | } else { |
|
|
260 | $grp->result ($_[0]); |
|
|
261 | } |
|
|
262 | }; |
|
|
263 | |
|
|
264 | $grp |
|
|
265 | } |
|
|
266 | |
|
|
267 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
340 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
268 | |
341 | |
269 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
342 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
270 | reading at byte offset C<$in_offset>, and starts writing at the current |
343 | reading at byte offset C<$in_offset>, and starts writing at the current |
271 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
344 | file offset of C<$out_fh>. Because of that, it is not safe to issue more |
… | |
… | |
326 | =item aio_unlink $pathname, $callback->($status) |
399 | =item aio_unlink $pathname, $callback->($status) |
327 | |
400 | |
328 | Asynchronously unlink (delete) a file and call the callback with the |
401 | Asynchronously unlink (delete) a file and call the callback with the |
329 | result code. |
402 | result code. |
330 | |
403 | |
|
|
404 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
|
|
405 | |
|
|
406 | [EXPERIMENTAL] |
|
|
407 | |
|
|
408 | Asynchronously create a device node (or fifo). See mknod(2). |
|
|
409 | |
|
|
410 | The only (POSIX-) portable way of calling this function is: |
|
|
411 | |
|
|
412 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
|
|
413 | |
331 | =item aio_link $srcpath, $dstpath, $callback->($status) |
414 | =item aio_link $srcpath, $dstpath, $callback->($status) |
332 | |
415 | |
333 | Asynchronously create a new link to the existing object at C<$srcpath> at |
416 | Asynchronously create a new link to the existing object at C<$srcpath> at |
334 | the path C<$dstpath> and call the callback with the result code. |
417 | the path C<$dstpath> and call the callback with the result code. |
335 | |
418 | |
336 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
419 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
337 | |
420 | |
338 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
421 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
339 | the path C<$dstpath> and call the callback with the result code. |
422 | the path C<$dstpath> and call the callback with the result code. |
|
|
423 | |
|
|
424 | =item aio_readlink $path, $callback->($link) |
|
|
425 | |
|
|
426 | Asynchronously read the symlink specified by C<$path> and pass it to |
|
|
427 | the callback. If an error occurs, nothing or undef gets passed to the |
|
|
428 | callback. |
340 | |
429 | |
341 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
430 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
342 | |
431 | |
343 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
432 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
344 | rename(2) and call the callback with the result code. |
433 | rename(2) and call the callback with the result code. |
… | |
… | |
355 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
444 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
356 | |
445 | |
357 | The callback a single argument which is either C<undef> or an array-ref |
446 | The callback a single argument which is either C<undef> or an array-ref |
358 | with the filenames. |
447 | with the filenames. |
359 | |
448 | |
|
|
449 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
|
|
450 | |
|
|
451 | Try to copy the I<file> (directories not supported as either source or |
|
|
452 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
453 | the C<0> (error) or C<-1> ok. |
|
|
454 | |
|
|
455 | This is a composite request that it creates the destination file with |
|
|
456 | mode 0200 and copies the contents of the source file into it using |
|
|
457 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
|
|
458 | uid/gid, in that order. |
|
|
459 | |
|
|
460 | If an error occurs, the partial destination file will be unlinked, if |
|
|
461 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
462 | errors are being ignored. |
|
|
463 | |
|
|
464 | =cut |
|
|
465 | |
|
|
466 | sub aio_copy($$;$) { |
|
|
467 | aio_block { |
|
|
468 | my ($src, $dst, $cb) = @_; |
|
|
469 | |
|
|
470 | my $pri = aioreq_pri; |
|
|
471 | my $grp = aio_group $cb; |
|
|
472 | |
|
|
473 | aioreq_pri $pri; |
|
|
474 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
475 | if (my $src_fh = $_[0]) { |
|
|
476 | my @stat = stat $src_fh; |
|
|
477 | |
|
|
478 | aioreq_pri $pri; |
|
|
479 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
480 | if (my $dst_fh = $_[0]) { |
|
|
481 | aioreq_pri $pri; |
|
|
482 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
483 | if ($_[0] == $stat[7]) { |
|
|
484 | $grp->result (0); |
|
|
485 | close $src_fh; |
|
|
486 | |
|
|
487 | # those should not normally block. should. should. |
|
|
488 | utime $stat[8], $stat[9], $dst; |
|
|
489 | chmod $stat[2] & 07777, $dst_fh; |
|
|
490 | chown $stat[4], $stat[5], $dst_fh; |
|
|
491 | close $dst_fh; |
|
|
492 | } else { |
|
|
493 | $grp->result (-1); |
|
|
494 | close $src_fh; |
|
|
495 | close $dst_fh; |
|
|
496 | |
|
|
497 | aioreq $pri; |
|
|
498 | add $grp aio_unlink $dst; |
|
|
499 | } |
|
|
500 | }; |
|
|
501 | } else { |
|
|
502 | $grp->result (-1); |
|
|
503 | } |
|
|
504 | }, |
|
|
505 | |
|
|
506 | } else { |
|
|
507 | $grp->result (-1); |
|
|
508 | } |
|
|
509 | }; |
|
|
510 | |
|
|
511 | $grp |
|
|
512 | } |
|
|
513 | } |
|
|
514 | |
|
|
515 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
516 | |
|
|
517 | Try to move the I<file> (directories not supported as either source or |
|
|
518 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
519 | the C<0> (error) or C<-1> ok. |
|
|
520 | |
|
|
521 | This is a composite request that tries to rename(2) the file first. If |
|
|
522 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
523 | that is successful, unlinking the C<$srcpath>. |
|
|
524 | |
|
|
525 | =cut |
|
|
526 | |
|
|
527 | sub aio_move($$;$) { |
|
|
528 | aio_block { |
|
|
529 | my ($src, $dst, $cb) = @_; |
|
|
530 | |
|
|
531 | my $pri = aioreq_pri; |
|
|
532 | my $grp = aio_group $cb; |
|
|
533 | |
|
|
534 | aioreq_pri $pri; |
|
|
535 | add $grp aio_rename $src, $dst, sub { |
|
|
536 | if ($_[0] && $! == EXDEV) { |
|
|
537 | aioreq_pri $pri; |
|
|
538 | add $grp aio_copy $src, $dst, sub { |
|
|
539 | $grp->result ($_[0]); |
|
|
540 | |
|
|
541 | if (!$_[0]) { |
|
|
542 | aioreq_pri $pri; |
|
|
543 | add $grp aio_unlink $src; |
|
|
544 | } |
|
|
545 | }; |
|
|
546 | } else { |
|
|
547 | $grp->result ($_[0]); |
|
|
548 | } |
|
|
549 | }; |
|
|
550 | |
|
|
551 | $grp |
|
|
552 | } |
|
|
553 | } |
|
|
554 | |
360 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
555 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
361 | |
556 | |
362 | [EXPERIMENTAL due to internal aio_group use] |
|
|
363 | |
|
|
364 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
557 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
365 | separate the entries of directory C<$path> into two sets of names, ones |
558 | efficiently separate the entries of directory C<$path> into two sets of |
366 | you can recurse into (directories or links to them), and ones you cannot |
559 | names, directories you can recurse into (directories), and ones you cannot |
367 | recurse into (everything else). |
560 | recurse into (everything else, including symlinks to directories). |
368 | |
561 | |
369 | C<aio_scandir> is a composite request that creates of many sub requests_ |
562 | C<aio_scandir> is a composite request that creates of many sub requests_ |
370 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
563 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
371 | this function generates. If it is C<< <= 0 >>, then a suitable default |
564 | this function generates. If it is C<< <= 0 >>, then a suitable default |
372 | will be chosen (currently 6). |
565 | will be chosen (currently 4). |
373 | |
566 | |
374 | On error, the callback is called without arguments, otherwise it receives |
567 | On error, the callback is called without arguments, otherwise it receives |
375 | two array-refs with path-relative entry names. |
568 | two array-refs with path-relative entry names. |
376 | |
569 | |
377 | Example: |
570 | Example: |
… | |
… | |
412 | directory counting heuristic. |
605 | directory counting heuristic. |
413 | |
606 | |
414 | =cut |
607 | =cut |
415 | |
608 | |
416 | sub aio_scandir($$$) { |
609 | sub aio_scandir($$$) { |
|
|
610 | aio_block { |
417 | my ($path, $maxreq, $cb) = @_; |
611 | my ($path, $maxreq, $cb) = @_; |
418 | |
612 | |
|
|
613 | my $pri = aioreq_pri; |
|
|
614 | |
419 | my $grp = aio_group $cb; |
615 | my $grp = aio_group $cb; |
420 | |
616 | |
421 | $maxreq = 6 if $maxreq <= 0; |
617 | $maxreq = 4 if $maxreq <= 0; |
422 | |
618 | |
423 | # stat once |
619 | # stat once |
|
|
620 | aioreq_pri $pri; |
424 | add $grp aio_stat $path, sub { |
621 | add $grp aio_stat $path, sub { |
425 | return $grp->result () if $_[0]; |
622 | return $grp->result () if $_[0]; |
426 | my $now = time; |
623 | my $now = time; |
427 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
624 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
428 | |
625 | |
429 | # read the directory entries |
626 | # read the directory entries |
|
|
627 | aioreq_pri $pri; |
430 | add $grp aio_readdir $path, sub { |
628 | add $grp aio_readdir $path, sub { |
431 | my $entries = shift |
629 | my $entries = shift |
432 | or return $grp->result (); |
630 | or return $grp->result (); |
433 | |
631 | |
434 | # stat the dir another time |
632 | # stat the dir another time |
|
|
633 | aioreq_pri $pri; |
435 | add $grp aio_stat $path, sub { |
634 | add $grp aio_stat $path, sub { |
436 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
635 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
437 | |
636 | |
438 | my $ndirs; |
637 | my $ndirs; |
439 | |
638 | |
440 | # take the slow route if anything looks fishy |
639 | # take the slow route if anything looks fishy |
441 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
640 | if ($hash1 ne $hash2 or (stat _)[9] == $now) { |
442 | $ndirs = -1; |
641 | $ndirs = -1; |
443 | } else { |
642 | } else { |
444 | # if nlink == 2, we are finished |
643 | # if nlink == 2, we are finished |
445 | # on non-posix-fs's, we rely on nlink < 2 |
644 | # on non-posix-fs's, we rely on nlink < 2 |
446 | $ndirs = (stat _)[3] - 2 |
645 | $ndirs = (stat _)[3] - 2 |
447 | or return $grp->result ([], $entries); |
646 | or return $grp->result ([], $entries); |
448 | } |
647 | } |
449 | |
648 | |
450 | # sort into likely dirs and likely nondirs |
649 | # sort into likely dirs and likely nondirs |
451 | # dirs == files without ".", short entries first |
650 | # dirs == files without ".", short entries first |
452 | $entries = [map $_->[0], |
651 | $entries = [map $_->[0], |
453 | sort { $b->[1] cmp $a->[1] } |
652 | sort { $b->[1] cmp $a->[1] } |
454 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
653 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
455 | @$entries]; |
654 | @$entries]; |
456 | |
655 | |
457 | my (@dirs, @nondirs); |
656 | my (@dirs, @nondirs); |
458 | |
657 | |
459 | my ($statcb, $schedcb); |
|
|
460 | my $nreq = 0; |
|
|
461 | |
|
|
462 | my $statgrp = add $grp aio_group; |
658 | my $statgrp = add $grp aio_group sub { |
463 | |
|
|
464 | $schedcb = sub { |
|
|
465 | if (@$entries) { |
|
|
466 | if ($nreq < $maxreq) { |
|
|
467 | my $ent = pop @$entries; |
|
|
468 | $nreq++; |
|
|
469 | add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
|
|
470 | } |
|
|
471 | } elsif (!$nreq) { |
|
|
472 | # finished |
|
|
473 | $statgrp->cancel; |
|
|
474 | undef $statcb; |
|
|
475 | undef $schedcb; |
|
|
476 | $grp->result (\@dirs, \@nondirs); |
659 | $grp->result (\@dirs, \@nondirs); |
477 | } |
660 | }; |
|
|
661 | |
|
|
662 | limit $statgrp $maxreq; |
|
|
663 | feed $statgrp sub { |
|
|
664 | return unless @$entries; |
|
|
665 | my $entry = pop @$entries; |
|
|
666 | |
|
|
667 | aioreq_pri $pri; |
|
|
668 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
669 | if ($_[0] < 0) { |
|
|
670 | push @nondirs, $entry; |
|
|
671 | } else { |
|
|
672 | # need to check for real directory |
|
|
673 | aioreq_pri $pri; |
|
|
674 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
675 | if (-d _) { |
|
|
676 | push @dirs, $entry; |
|
|
677 | |
|
|
678 | unless (--$ndirs) { |
|
|
679 | push @nondirs, @$entries; |
|
|
680 | feed $statgrp; |
|
|
681 | } |
|
|
682 | } else { |
|
|
683 | push @nondirs, $entry; |
|
|
684 | } |
|
|
685 | } |
|
|
686 | } |
|
|
687 | }; |
|
|
688 | }; |
478 | }; |
689 | }; |
479 | $statcb = sub { |
|
|
480 | my ($status, $entry) = @_; |
|
|
481 | |
|
|
482 | if ($status < 0) { |
|
|
483 | $nreq--; |
|
|
484 | push @nondirs, $entry; |
|
|
485 | &$schedcb; |
|
|
486 | } else { |
|
|
487 | # need to check for real directory |
|
|
488 | add $grp aio_lstat "$path/$entry", sub { |
|
|
489 | $nreq--; |
|
|
490 | |
|
|
491 | if (-d _) { |
|
|
492 | push @dirs, $entry; |
|
|
493 | |
|
|
494 | if (!--$ndirs) { |
|
|
495 | push @nondirs, @$entries; |
|
|
496 | $entries = []; |
|
|
497 | } |
|
|
498 | } else { |
|
|
499 | push @nondirs, $entry; |
|
|
500 | } |
|
|
501 | |
|
|
502 | &$schedcb; |
|
|
503 | } |
|
|
504 | } |
|
|
505 | }; |
|
|
506 | |
|
|
507 | &$schedcb while @$entries && $nreq < $maxreq; |
|
|
508 | }; |
690 | }; |
509 | }; |
691 | }; |
|
|
692 | |
|
|
693 | $grp |
510 | }; |
694 | } |
511 | |
|
|
512 | $grp |
|
|
513 | } |
695 | } |
514 | |
696 | |
515 | =item aio_fsync $fh, $callback->($status) |
697 | =item aio_fsync $fh, $callback->($status) |
516 | |
698 | |
517 | Asynchronously call fsync on the given filehandle and call the callback |
699 | Asynchronously call fsync on the given filehandle and call the callback |
… | |
… | |
525 | If this call isn't available because your OS lacks it or it couldn't be |
707 | If this call isn't available because your OS lacks it or it couldn't be |
526 | detected, it will be emulated by calling C<fsync> instead. |
708 | detected, it will be emulated by calling C<fsync> instead. |
527 | |
709 | |
528 | =item aio_group $callback->(...) |
710 | =item aio_group $callback->(...) |
529 | |
711 | |
530 | [EXPERIMENTAL] |
|
|
531 | |
|
|
532 | This is a very special aio request: Instead of doing something, it is a |
712 | This is a very special aio request: Instead of doing something, it is a |
533 | container for other aio requests, which is useful if you want to bundle |
713 | container for other aio requests, which is useful if you want to bundle |
534 | many requests into a single, composite, request. |
714 | many requests into a single, composite, request with a definite callback |
|
|
715 | and the ability to cancel the whole request with its subrequests. |
535 | |
716 | |
536 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
717 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
537 | for more info. |
718 | for more info. |
538 | |
719 | |
539 | Example: |
720 | Example: |
… | |
… | |
558 | phase and still requires a worker thread. Thus, the callback will not |
739 | phase and still requires a worker thread. Thus, the callback will not |
559 | be executed immediately but only after other requests in the queue have |
740 | be executed immediately but only after other requests in the queue have |
560 | entered their execution phase. This can be used to measure request |
741 | entered their execution phase. This can be used to measure request |
561 | latency. |
742 | latency. |
562 | |
743 | |
563 | =item IO::AIO::aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
744 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
564 | |
745 | |
565 | Mainly used for debugging and benchmarking, this aio request puts one of |
746 | Mainly used for debugging and benchmarking, this aio request puts one of |
566 | the request workers to sleep for the given time. |
747 | the request workers to sleep for the given time. |
567 | |
748 | |
568 | While it is theoretically handy to have simple I/O scheduling requests |
749 | While it is theoretically handy to have simple I/O scheduling requests |
569 | like sleep and file handle readable/writable, the overhead this creates |
750 | like sleep and file handle readable/writable, the overhead this creates is |
570 | is immense, so do not use this function except to put your application |
751 | immense (it blocks a thread for a long time) so do not use this function |
571 | under artificial I/O pressure. |
752 | except to put your application under artificial I/O pressure. |
572 | |
753 | |
573 | =back |
754 | =back |
574 | |
755 | |
575 | =head2 IO::AIO::REQ CLASS |
756 | =head2 IO::AIO::REQ CLASS |
576 | |
757 | |
577 | All non-aggregate C<aio_*> functions return an object of this class when |
758 | All non-aggregate C<aio_*> functions return an object of this class when |
578 | called in non-void context. |
759 | called in non-void context. |
579 | |
|
|
580 | A request always moves through the following five states in its lifetime, |
|
|
581 | in order: B<ready> (request has been created, but has not been executed |
|
|
582 | yet), B<execute> (request is currently being executed), B<pending> |
|
|
583 | (request has been executed but callback has not been called yet), |
|
|
584 | B<result> (results are being processed synchronously, includes calling the |
|
|
585 | callback) and B<done> (request has reached the end of its lifetime and |
|
|
586 | holds no resources anymore). |
|
|
587 | |
760 | |
588 | =over 4 |
761 | =over 4 |
589 | |
762 | |
590 | =item cancel $req |
763 | =item cancel $req |
591 | |
764 | |
… | |
… | |
645 | =item * They can also can also be added to other IO::AIO::GRP objects. |
818 | =item * They can also can also be added to other IO::AIO::GRP objects. |
646 | |
819 | |
647 | =item * You must not add requests to a group from within the group callback (or |
820 | =item * You must not add requests to a group from within the group callback (or |
648 | any later time). |
821 | any later time). |
649 | |
822 | |
650 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
651 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
652 | this kind of concurrency-limiting. |
|
|
653 | |
|
|
654 | =back |
823 | =back |
655 | |
824 | |
656 | Their lifetime, simplified, looks like this: when they are empty, they |
825 | Their lifetime, simplified, looks like this: when they are empty, they |
657 | will finish very quickly. If they contain only requests that are in the |
826 | will finish very quickly. If they contain only requests that are in the |
658 | C<done> state, they will also finish. Otherwise they will continue to |
827 | C<done> state, they will also finish. Otherwise they will continue to |
… | |
… | |
673 | be added, including other groups, as long as you do not create circular |
842 | be added, including other groups, as long as you do not create circular |
674 | dependencies. |
843 | dependencies. |
675 | |
844 | |
676 | Returns all its arguments. |
845 | Returns all its arguments. |
677 | |
846 | |
|
|
847 | =item $grp->cancel_subs |
|
|
848 | |
|
|
849 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
850 | itself. Useful when you queued a lot of events but got a result early. |
|
|
851 | |
678 | =item $grp->result (...) |
852 | =item $grp->result (...) |
679 | |
853 | |
680 | Set the result value(s) that will be passed to the group callback when all |
854 | Set the result value(s) that will be passed to the group callback when all |
681 | subrequests have finished. By default, no argument will be passed. |
855 | subrequests have finished and set thre groups errno to the current value |
|
|
856 | of errno (just like calling C<errno> without an error number). By default, |
|
|
857 | no argument will be passed and errno is zero. |
|
|
858 | |
|
|
859 | =item $grp->errno ([$errno]) |
|
|
860 | |
|
|
861 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
862 | when the argument is missing. |
|
|
863 | |
|
|
864 | Every aio request has an associated errno value that is restored when |
|
|
865 | the callback is invoked. This method lets you change this value from its |
|
|
866 | default (0). |
|
|
867 | |
|
|
868 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
869 | before the call to C<result>, or call c<errno> after it. |
682 | |
870 | |
683 | =item feed $grp $callback->($grp) |
871 | =item feed $grp $callback->($grp) |
684 | |
|
|
685 | [VERY EXPERIMENTAL] |
|
|
686 | |
872 | |
687 | Sets a feeder/generator on this group: every group can have an attached |
873 | Sets a feeder/generator on this group: every group can have an attached |
688 | generator that generates requests if idle. The idea behind this is that, |
874 | generator that generates requests if idle. The idea behind this is that, |
689 | although you could just queue as many requests as you want in a group, |
875 | although you could just queue as many requests as you want in a group, |
690 | this might starve other requests for a potentially long time. For |
876 | this might starve other requests for a potentially long time. For |
… | |
… | |
727 | |
913 | |
728 | =back |
914 | =back |
729 | |
915 | |
730 | =head2 SUPPORT FUNCTIONS |
916 | =head2 SUPPORT FUNCTIONS |
731 | |
917 | |
|
|
918 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
919 | |
732 | =over 4 |
920 | =over 4 |
733 | |
921 | |
734 | =item $fileno = IO::AIO::poll_fileno |
922 | =item $fileno = IO::AIO::poll_fileno |
735 | |
923 | |
736 | Return the I<request result pipe file descriptor>. This filehandle must be |
924 | Return the I<request result pipe file descriptor>. This filehandle must be |
… | |
… | |
740 | |
928 | |
741 | See C<poll_cb> for an example. |
929 | See C<poll_cb> for an example. |
742 | |
930 | |
743 | =item IO::AIO::poll_cb |
931 | =item IO::AIO::poll_cb |
744 | |
932 | |
745 | Process all outstanding events on the result pipe. You have to call this |
933 | Process some outstanding events on the result pipe. You have to call this |
746 | regularly. Returns the number of events processed. Returns immediately |
934 | regularly. Returns the number of events processed. Returns immediately |
747 | when no events are outstanding. |
935 | when no events are outstanding. The amount of events processed depends on |
|
|
936 | the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. |
|
|
937 | |
|
|
938 | If not all requests were processed for whatever reason, the filehandle |
|
|
939 | will still be ready when C<poll_cb> returns. |
748 | |
940 | |
749 | Example: Install an Event watcher that automatically calls |
941 | Example: Install an Event watcher that automatically calls |
750 | IO::AIO::poll_cb with high priority: |
942 | IO::AIO::poll_cb with high priority: |
751 | |
943 | |
752 | Event->io (fd => IO::AIO::poll_fileno, |
944 | Event->io (fd => IO::AIO::poll_fileno, |
753 | poll => 'r', async => 1, |
945 | poll => 'r', async => 1, |
754 | cb => \&IO::AIO::poll_cb); |
946 | cb => \&IO::AIO::poll_cb); |
755 | |
947 | |
|
|
948 | =item IO::AIO::max_poll_reqs $nreqs |
|
|
949 | |
|
|
950 | =item IO::AIO::max_poll_time $seconds |
|
|
951 | |
|
|
952 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
953 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
954 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
955 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
956 | of time C<poll_cb> is allowed to use). |
|
|
957 | |
|
|
958 | Setting C<max_poll_time> to a non-zero value creates an overhead of one |
|
|
959 | syscall per request processed, which is not normally a problem unless your |
|
|
960 | callbacks are really really fast or your OS is really really slow (I am |
|
|
961 | not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead. |
|
|
962 | |
|
|
963 | Setting these is useful if you want to ensure some level of |
|
|
964 | interactiveness when perl is not fast enough to process all requests in |
|
|
965 | time. |
|
|
966 | |
|
|
967 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
|
|
968 | |
|
|
969 | Example: Install an Event watcher that automatically calls |
|
|
970 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
|
|
971 | program get the CPU sometimes even under high AIO load. |
|
|
972 | |
|
|
973 | # try not to spend much more than 0.1s in poll_cb |
|
|
974 | IO::AIO::max_poll_time 0.1; |
|
|
975 | |
|
|
976 | # use a low priority so other tasks have priority |
|
|
977 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
978 | poll => 'r', nice => 1, |
|
|
979 | cb => &IO::AIO::poll_cb); |
|
|
980 | |
756 | =item IO::AIO::poll_wait |
981 | =item IO::AIO::poll_wait |
757 | |
982 | |
|
|
983 | If there are any outstanding requests and none of them in the result |
758 | Wait till the result filehandle becomes ready for reading (simply does a |
984 | phase, wait till the result filehandle becomes ready for reading (simply |
759 | C<select> on the filehandle. This is useful if you want to synchronously wait |
985 | does a C<select> on the filehandle. This is useful if you want to |
760 | for some requests to finish). |
986 | synchronously wait for some requests to finish). |
761 | |
987 | |
762 | See C<nreqs> for an example. |
988 | See C<nreqs> for an example. |
763 | |
989 | |
|
|
990 | =item IO::AIO::poll |
|
|
991 | |
|
|
992 | Waits until some requests have been handled. |
|
|
993 | |
|
|
994 | Returns the number of requests processed, but is otherwise strictly |
|
|
995 | equivalent to: |
|
|
996 | |
|
|
997 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
998 | |
764 | =item IO::AIO::nreqs |
999 | =item IO::AIO::flush |
765 | |
1000 | |
766 | Returns the number of requests currently outstanding (i.e. for which their |
1001 | Wait till all outstanding AIO requests have been handled. |
767 | callback has not been invoked yet). |
|
|
768 | |
1002 | |
769 | Example: wait till there are no outstanding requests anymore: |
1003 | Strictly equivalent to: |
770 | |
1004 | |
771 | IO::AIO::poll_wait, IO::AIO::poll_cb |
1005 | IO::AIO::poll_wait, IO::AIO::poll_cb |
772 | while IO::AIO::nreqs; |
1006 | while IO::AIO::nreqs; |
773 | |
1007 | |
774 | =item IO::AIO::flush |
1008 | =head3 CONTROLLING THE NUMBER OF THREADS |
775 | |
|
|
776 | Wait till all outstanding AIO requests have been handled. |
|
|
777 | |
|
|
778 | Strictly equivalent to: |
|
|
779 | |
|
|
780 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
781 | while IO::AIO::nreqs; |
|
|
782 | |
|
|
783 | =item IO::AIO::poll |
|
|
784 | |
|
|
785 | Waits until some requests have been handled. |
|
|
786 | |
|
|
787 | Strictly equivalent to: |
|
|
788 | |
|
|
789 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
790 | if IO::AIO::nreqs; |
|
|
791 | |
1009 | |
792 | =item IO::AIO::min_parallel $nthreads |
1010 | =item IO::AIO::min_parallel $nthreads |
793 | |
1011 | |
794 | Set the minimum number of AIO threads to C<$nthreads>. The current |
1012 | Set the minimum number of AIO threads to C<$nthreads>. The current |
795 | default is C<8>, which means eight asynchronous operations can execute |
1013 | default is C<8>, which means eight asynchronous operations can execute |
796 | concurrently at any one time (the number of outstanding requests, |
1014 | concurrently at any one time (the number of outstanding requests, |
797 | however, is unlimited). |
1015 | however, is unlimited). |
798 | |
1016 | |
799 | IO::AIO starts threads only on demand, when an AIO request is queued and |
1017 | IO::AIO starts threads only on demand, when an AIO request is queued and |
800 | no free thread exists. |
1018 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
1019 | create demand for a hundred threads, even if it turns out that everything |
|
|
1020 | is in the cache and could have been processed faster by a single thread. |
801 | |
1021 | |
802 | It is recommended to keep the number of threads relatively low, as some |
1022 | It is recommended to keep the number of threads relatively low, as some |
803 | Linux kernel versions will scale negatively with the number of threads |
1023 | Linux kernel versions will scale negatively with the number of threads |
804 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
1024 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
805 | versions, 4-32 threads should be fine. |
1025 | versions, 4-32 threads should be fine. |
… | |
… | |
819 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1039 | This module automatically runs C<max_parallel 0> at program end, to ensure |
820 | that all threads are killed and that there are no outstanding requests. |
1040 | that all threads are killed and that there are no outstanding requests. |
821 | |
1041 | |
822 | Under normal circumstances you don't need to call this function. |
1042 | Under normal circumstances you don't need to call this function. |
823 | |
1043 | |
|
|
1044 | =item IO::AIO::max_idle $nthreads |
|
|
1045 | |
|
|
1046 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
|
|
1047 | threads that did not get a request to process within 10 seconds). That |
|
|
1048 | means if a thread becomes idle while C<$nthreads> other threads are also |
|
|
1049 | idle, it will free its resources and exit. |
|
|
1050 | |
|
|
1051 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1052 | to allow for extremely high load situations, but want to free resources |
|
|
1053 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1054 | |
|
|
1055 | The default is probably ok in most situations, especially if thread |
|
|
1056 | creation is fast. If thread creation is very slow on your system you might |
|
|
1057 | want to use larger values. |
|
|
1058 | |
824 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
1059 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
825 | |
1060 | |
826 | [DEPRECATED] |
1061 | This is a very bad function to use in interactive programs because it |
|
|
1062 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1063 | use an C<aio_group> together with a feed callback. |
827 | |
1064 | |
828 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1065 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
829 | try to queue up more than this number of requests, the caller will block until |
1066 | to queue up more than this number of requests, the next call to the |
830 | some requests have been handled. |
1067 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
1068 | function will block until the limit is no longer exceeded. |
831 | |
1069 | |
832 | The default is very large, so normally there is no practical limit. If you |
1070 | The default value is very large, so there is no practical limit on the |
833 | queue up many requests in a loop it often improves speed if you set |
1071 | number of outstanding requests. |
834 | this to a relatively low number, such as C<100>. |
|
|
835 | |
1072 | |
836 | This function does not work well together with C<aio_group>'s, and their |
1073 | You can still queue as many requests as you want. Therefore, |
837 | feeder interface is better suited to limiting concurrency, so do not use |
1074 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
838 | this function. |
1075 | as a stop gap to shield against fatal memory overflow (with large values). |
839 | |
1076 | |
840 | Under normal circumstances you don't need to call this function. |
1077 | =head3 STATISTICAL INFORMATION |
|
|
1078 | |
|
|
1079 | =item IO::AIO::nreqs |
|
|
1080 | |
|
|
1081 | Returns the number of requests currently in the ready, execute or pending |
|
|
1082 | states (i.e. for which their callback has not been invoked yet). |
|
|
1083 | |
|
|
1084 | Example: wait till there are no outstanding requests anymore: |
|
|
1085 | |
|
|
1086 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1087 | while IO::AIO::nreqs; |
|
|
1088 | |
|
|
1089 | =item IO::AIO::nready |
|
|
1090 | |
|
|
1091 | Returns the number of requests currently in the ready state (not yet |
|
|
1092 | executed). |
|
|
1093 | |
|
|
1094 | =item IO::AIO::npending |
|
|
1095 | |
|
|
1096 | Returns the number of requests currently in the pending state (executed, |
|
|
1097 | but not yet processed by poll_cb). |
841 | |
1098 | |
842 | =back |
1099 | =back |
843 | |
1100 | |
844 | =cut |
1101 | =cut |
845 | |
1102 | |
… | |
… | |
859 | *$sym |
1116 | *$sym |
860 | } |
1117 | } |
861 | |
1118 | |
862 | min_parallel 8; |
1119 | min_parallel 8; |
863 | |
1120 | |
864 | END { |
1121 | END { flush } |
865 | max_parallel 0; |
|
|
866 | } |
|
|
867 | |
1122 | |
868 | 1; |
1123 | 1; |
869 | |
1124 | |
870 | =head2 FORK BEHAVIOUR |
1125 | =head2 FORK BEHAVIOUR |
871 | |
1126 | |
872 | This module should do "the right thing" when the process using it forks: |
1127 | This module should do "the right thing" when the process using it forks: |
873 | |
1128 | |
874 | Before the fork, IO::AIO enters a quiescent state where no requests |
1129 | Before the fork, IO::AIO enters a quiescent state where no requests |
875 | can be added in other threads and no results will be processed. After |
1130 | can be added in other threads and no results will be processed. After |
876 | the fork the parent simply leaves the quiescent state and continues |
1131 | the fork the parent simply leaves the quiescent state and continues |
877 | request/result processing, while the child clears the request/result |
1132 | request/result processing, while the child frees the request/result queue |
878 | queue (so the requests started before the fork will only be handled in |
1133 | (so that the requests started before the fork will only be handled in the |
879 | the parent). Threads will be started on demand until the limit ste in the |
1134 | parent). Threads will be started on demand until the limit set in the |
880 | parent process has been reached again. |
1135 | parent process has been reached again. |
881 | |
1136 | |
882 | In short: the parent will, after a short pause, continue as if fork had |
1137 | In short: the parent will, after a short pause, continue as if fork had |
883 | not been called, while the child will act as if IO::AIO has not been used |
1138 | not been called, while the child will act as if IO::AIO has not been used |
884 | yet. |
1139 | yet. |
885 | |
1140 | |
886 | =head2 MEMORY USAGE |
1141 | =head2 MEMORY USAGE |
887 | |
1142 | |
|
|
1143 | Per-request usage: |
|
|
1144 | |
888 | Each aio request uses - depending on your architecture - around 128 bytes |
1145 | Each aio request uses - depending on your architecture - around 100-200 |
889 | of memory. In addition, stat requests need a stat buffer (possibly a few |
1146 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
890 | hundred bytes). Perl scalars and other data passed into aio requests will |
1147 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
891 | also be locked. |
1148 | scalars and other data passed into aio requests will also be locked and |
|
|
1149 | will consume memory till the request has entered the done state. |
892 | |
1150 | |
893 | This is now awfully much, so queuing lots of requests is not usually a |
1151 | This is now awfully much, so queuing lots of requests is not usually a |
894 | problem. |
1152 | problem. |
895 | |
1153 | |
896 | Each thread needs a stack area which is usually around 16k, sometimes much |
1154 | Per-thread usage: |
897 | larger, depending on the OS. |
1155 | |
|
|
1156 | In the execution phase, some aio requests require more memory for |
|
|
1157 | temporary buffers, and each thread requires a stack and other data |
|
|
1158 | structures (usually around 16k-128k, depending on the OS). |
|
|
1159 | |
|
|
1160 | =head1 KNOWN BUGS |
|
|
1161 | |
|
|
1162 | Known bugs will be fixed in the next release. |
898 | |
1163 | |
899 | =head1 SEE ALSO |
1164 | =head1 SEE ALSO |
900 | |
1165 | |
901 | L<Coro::AIO>. |
1166 | L<Coro::AIO>. |
902 | |
1167 | |