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51 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
52 | |
52 | |
53 | This module implements asynchronous I/O using whatever means your |
53 | This module implements asynchronous I/O using whatever means your |
54 | operating system supports. |
54 | operating system supports. |
55 | |
55 | |
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56 | Asynchronous means that operations that can normally block your program |
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57 | (e.g. reading from disk) will be done asynchronously: the operation |
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58 | will still block, but you can do something else in the meantime. This |
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59 | is extremely useful for programs that need to stay interactive even |
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60 | when doing heavy I/O (GUI programs, high performance network servers |
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61 | etc.), but can also be used to easily do operations in parallel that are |
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62 | normally done sequentially, e.g. stat'ing many files, which is much faster |
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63 | on a RAID volume or over NFS when you do a number of stat operations |
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64 | concurrently. |
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65 | |
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66 | While this works on all types of file descriptors (for example sockets), |
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67 | using these functions on file descriptors that support nonblocking |
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68 | operation (again, sockets, pipes etc.) is very inefficient. Use an event |
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69 | loop for that (such as the L<Event|Event> module): IO::AIO will naturally |
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70 | fit into such an event loop itself. |
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71 | |
56 | Currently, a number of threads are started that execute your read/writes |
72 | 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 |
73 | 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 |
74 | 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 |
75 | 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 |
76 | functions available on many operating systems. However, they are often |
61 | (Linux doesn't allow them on normal files currently, for example), |
77 | 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 |
78 | files currently, for example), and they would only support aio_read and |
63 | functionality would have to be implemented using threads anyway. |
79 | aio_write, so the remaining functionality would have to be implemented |
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80 | using threads anyway. |
64 | |
81 | |
65 | Although the module will work with in the presence of other threads, |
82 | 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 |
83 | 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 |
84 | locking yourself, always call C<poll_cb> from within the same thread, or |
68 | call C<poll_cb> (or other C<aio_> functions) recursively. |
85 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
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86 | |
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87 | =head2 EXAMPLE |
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88 | |
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89 | This is a simple example that uses the Event module and loads |
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90 | F</etc/passwd> asynchronously: |
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91 | |
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92 | use Fcntl; |
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93 | use Event; |
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94 | use IO::AIO; |
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95 | |
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96 | # register the IO::AIO callback with Event |
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97 | Event->io (fd => IO::AIO::poll_fileno, |
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98 | poll => 'r', |
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99 | cb => \&IO::AIO::poll_cb); |
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100 | |
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101 | # queue the request to open /etc/passwd |
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102 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
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103 | my $fh = $_[0] |
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104 | or die "error while opening: $!"; |
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105 | |
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106 | # stat'ing filehandles is generally non-blocking |
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107 | my $size = -s $fh; |
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108 | |
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109 | # queue a request to read the file |
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110 | my $contents; |
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111 | aio_read $fh, 0, $size, $contents, 0, sub { |
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112 | $_[0] == $size |
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113 | or die "short read: $!"; |
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114 | |
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115 | close $fh; |
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116 | |
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117 | # file contents now in $contents |
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118 | print $contents; |
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119 | |
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120 | # exit event loop and program |
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121 | Event::unloop; |
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122 | }; |
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123 | }; |
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124 | |
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125 | # possibly queue up other requests, or open GUI windows, |
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126 | # check for sockets etc. etc. |
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127 | |
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128 | # process events as long as there are some: |
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129 | Event::loop; |
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130 | |
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131 | =head1 REQUEST ANATOMY AND LIFETIME |
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132 | |
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133 | Every C<aio_*> function creates a request. which is a C data structure not |
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134 | directly visible to Perl. |
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135 | |
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136 | If called in non-void context, every request function returns a Perl |
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137 | object representing the request. In void context, nothing is returned, |
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138 | which saves a bit of memory. |
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139 | |
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140 | The perl object is a fairly standard ref-to-hash object. The hash contents |
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141 | are not used by IO::AIO so you are free to store anything you like in it. |
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142 | |
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143 | During their existance, aio requests travel through the following states, |
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144 | in order: |
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145 | |
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146 | =over 4 |
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147 | |
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148 | =item ready |
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149 | |
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150 | Immediately after a request is created it is put into the ready state, |
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151 | waiting for a thread to execute it. |
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152 | |
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153 | =item execute |
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154 | |
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155 | A thread has accepted the request for processing and is currently |
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156 | executing it (e.g. blocking in read). |
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157 | |
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158 | =item pending |
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159 | |
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160 | The request has been executed and is waiting for result processing. |
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161 | |
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162 | While request submission and execution is fully asynchronous, result |
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163 | processing is not and relies on the perl interpreter calling C<poll_cb> |
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164 | (or another function with the same effect). |
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165 | |
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166 | =item result |
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167 | |
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168 | The request results are processed synchronously by C<poll_cb>. |
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169 | |
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170 | The C<poll_cb> function will process all outstanding aio requests by |
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171 | calling their callbacks, freeing memory associated with them and managing |
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172 | any groups they are contained in. |
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173 | |
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174 | =item done |
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175 | |
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176 | Request has reached the end of its lifetime and holds no resources anymore |
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177 | (except possibly for the Perl object, but its connection to the actual |
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178 | aio request is severed and calling its methods will either do nothing or |
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179 | result in a runtime error). |
69 | |
180 | |
70 | =cut |
181 | =cut |
71 | |
182 | |
72 | package IO::AIO; |
183 | package IO::AIO; |
73 | |
184 | |
… | |
… | |
75 | use strict 'vars'; |
186 | use strict 'vars'; |
76 | |
187 | |
77 | use base 'Exporter'; |
188 | use base 'Exporter'; |
78 | |
189 | |
79 | BEGIN { |
190 | BEGIN { |
80 | our $VERSION = '2.0'; |
191 | our $VERSION = '2.1'; |
81 | |
192 | |
82 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
193 | 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 |
194 | 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 |
195 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
85 | aio_group aio_nop); |
196 | aio_copy aio_group aio_nop aio_mknod); |
86 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
197 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
87 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
198 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
88 | min_parallel max_parallel max_outstanding nreqs); |
199 | min_parallel max_parallel max_idle |
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200 | nreqs nready npending nthreads |
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201 | max_poll_time max_poll_reqs); |
89 | |
202 | |
90 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
203 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
91 | |
204 | |
92 | require XSLoader; |
205 | require XSLoader; |
93 | XSLoader::load ("IO::AIO", $VERSION); |
206 | XSLoader::load ("IO::AIO", $VERSION); |
… | |
… | |
124 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
237 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
125 | use something else. |
238 | use something else. |
126 | |
239 | |
127 | =over 4 |
240 | =over 4 |
128 | |
241 | |
129 | =item aioreq_pri $pri |
242 | =item $prev_pri = aioreq_pri [$pri] |
130 | |
243 | |
131 | Sets the priority for the next aio request. The default priority |
244 | Returns the priority value that would be used for the next request and, if |
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245 | C<$pri> is given, sets the priority for the next aio request. |
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246 | |
132 | is C<0>, the minimum and maximum priorities are C<-4> and C<4>, |
247 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
133 | respectively. Requests with higher priority will be serviced first. |
248 | and C<4>, respectively. Requests with higher priority will be serviced |
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249 | first. |
134 | |
250 | |
135 | The priority will be reset to C<0> after each call to one of the C<aio_> |
251 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
136 | functions. |
252 | functions. |
137 | |
253 | |
138 | Example: open a file with low priority, then read something from it with |
254 | Example: open a file with low priority, then read something from it with |
139 | higher priority so the read request is serviced before other low priority |
255 | higher priority so the read request is serviced before other low priority |
140 | open requests (potentially spamming the cache): |
256 | open requests (potentially spamming the cache): |
… | |
… | |
210 | |
326 | |
211 | aio_read $fh, 7, 15, $buffer, 0, sub { |
327 | aio_read $fh, 7, 15, $buffer, 0, sub { |
212 | $_[0] > 0 or die "read error: $!"; |
328 | $_[0] > 0 or die "read error: $!"; |
213 | print "read $_[0] bytes: <$buffer>\n"; |
329 | print "read $_[0] bytes: <$buffer>\n"; |
214 | }; |
330 | }; |
215 | |
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216 | =item aio_move $srcpath, $dstpath, $callback->($status) |
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217 | |
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218 | Try to move the I<file> (directories not supported as either source or |
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219 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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220 | the C<0> (error) or C<-1> ok. |
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221 | |
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222 | This is a composite request that tries to rename(2) the file first. If |
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223 | rename files with C<EXDEV>, it creates the destination file with mode 0200 |
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224 | and copies the contents of the source file into it using C<aio_sendfile>, |
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225 | followed by restoring atime, mtime, access mode and uid/gid, in that |
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226 | order, and unlinking the C<$srcpath>. |
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227 | |
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228 | If an error occurs, the partial destination file will be unlinked, if |
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229 | possible, except when setting atime, mtime, access mode and uid/gid, where |
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230 | errors are being ignored. |
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231 | |
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232 | =cut |
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233 | |
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234 | sub aio_move($$$) { |
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235 | my ($src, $dst, $cb) = @_; |
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236 | |
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237 | my $grp = aio_group $cb; |
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238 | |
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239 | add $grp aio_rename $src, $dst, sub { |
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240 | if ($_[0] && $! == EXDEV) { |
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241 | add $grp aio_open $src, O_RDONLY, 0, sub { |
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242 | if (my $src_fh = $_[0]) { |
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243 | my @stat = stat $src_fh; |
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244 | |
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245 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
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246 | if (my $dst_fh = $_[0]) { |
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247 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
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248 | close $src_fh; |
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249 | |
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250 | if ($_[0] == $stat[7]) { |
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251 | utime $stat[8], $stat[9], $dst; |
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252 | chmod $stat[2] & 07777, $dst_fh; |
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253 | chown $stat[4], $stat[5], $dst_fh; |
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254 | close $dst_fh; |
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255 | |
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256 | add $grp aio_unlink $src, sub { |
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257 | $grp->result ($_[0]); |
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258 | }; |
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259 | } else { |
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260 | my $errno = $!; |
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261 | add $grp aio_unlink $dst, sub { |
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262 | $! = $errno; |
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263 | $grp->result (-1); |
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264 | }; |
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265 | } |
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266 | }; |
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267 | } else { |
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268 | $grp->result (-1); |
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269 | } |
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270 | }, |
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271 | |
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272 | } else { |
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273 | $grp->result (-1); |
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274 | } |
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275 | }; |
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276 | } else { |
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277 | $grp->result ($_[0]); |
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278 | } |
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279 | }; |
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280 | |
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281 | $grp |
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282 | } |
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283 | |
331 | |
284 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
332 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
285 | |
333 | |
286 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
334 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
287 | reading at byte offset C<$in_offset>, and starts writing at the current |
335 | reading at byte offset C<$in_offset>, and starts writing at the current |
… | |
… | |
343 | =item aio_unlink $pathname, $callback->($status) |
391 | =item aio_unlink $pathname, $callback->($status) |
344 | |
392 | |
345 | Asynchronously unlink (delete) a file and call the callback with the |
393 | Asynchronously unlink (delete) a file and call the callback with the |
346 | result code. |
394 | result code. |
347 | |
395 | |
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396 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
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397 | |
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398 | [EXPERIMENTAL] |
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399 | |
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400 | Asynchronously create a device node (or fifo). See mknod(2). |
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401 | |
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402 | The only (POSIX-) portable way of calling this function is: |
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403 | |
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404 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
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405 | |
348 | =item aio_link $srcpath, $dstpath, $callback->($status) |
406 | =item aio_link $srcpath, $dstpath, $callback->($status) |
349 | |
407 | |
350 | Asynchronously create a new link to the existing object at C<$srcpath> at |
408 | Asynchronously create a new link to the existing object at C<$srcpath> at |
351 | the path C<$dstpath> and call the callback with the result code. |
409 | the path C<$dstpath> and call the callback with the result code. |
352 | |
410 | |
… | |
… | |
372 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
430 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
373 | |
431 | |
374 | The callback a single argument which is either C<undef> or an array-ref |
432 | The callback a single argument which is either C<undef> or an array-ref |
375 | with the filenames. |
433 | with the filenames. |
376 | |
434 | |
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435 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
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436 | |
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437 | Try to copy the I<file> (directories not supported as either source or |
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438 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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439 | the C<0> (error) or C<-1> ok. |
|
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440 | |
|
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441 | This is a composite request that it creates the destination file with |
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442 | mode 0200 and copies the contents of the source file into it using |
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443 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
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444 | uid/gid, in that order. |
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445 | |
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446 | If an error occurs, the partial destination file will be unlinked, if |
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447 | possible, except when setting atime, mtime, access mode and uid/gid, where |
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448 | errors are being ignored. |
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449 | |
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450 | =cut |
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451 | |
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452 | sub aio_copy($$;$) { |
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453 | my ($src, $dst, $cb) = @_; |
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454 | |
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455 | my $pri = aioreq_pri; |
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456 | my $grp = aio_group $cb; |
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457 | |
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458 | aioreq_pri $pri; |
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459 | add $grp aio_open $src, O_RDONLY, 0, sub { |
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460 | if (my $src_fh = $_[0]) { |
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461 | my @stat = stat $src_fh; |
|
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462 | |
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463 | aioreq_pri $pri; |
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464 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
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465 | if (my $dst_fh = $_[0]) { |
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466 | aioreq_pri $pri; |
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467 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
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468 | if ($_[0] == $stat[7]) { |
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469 | $grp->result (0); |
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470 | close $src_fh; |
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471 | |
|
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472 | # those should not normally block. should. should. |
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473 | utime $stat[8], $stat[9], $dst; |
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474 | chmod $stat[2] & 07777, $dst_fh; |
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475 | chown $stat[4], $stat[5], $dst_fh; |
|
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476 | close $dst_fh; |
|
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477 | } else { |
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478 | $grp->result (-1); |
|
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479 | close $src_fh; |
|
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480 | close $dst_fh; |
|
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481 | |
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482 | aioreq $pri; |
|
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483 | add $grp aio_unlink $dst; |
|
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484 | } |
|
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485 | }; |
|
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486 | } else { |
|
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487 | $grp->result (-1); |
|
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488 | } |
|
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489 | }, |
|
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490 | |
|
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491 | } else { |
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492 | $grp->result (-1); |
|
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493 | } |
|
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494 | }; |
|
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495 | |
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496 | $grp |
|
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497 | } |
|
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498 | |
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499 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
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500 | |
|
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501 | Try to move the I<file> (directories not supported as either source or |
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502 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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503 | the C<0> (error) or C<-1> ok. |
|
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504 | |
|
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505 | This is a composite request that tries to rename(2) the file first. If |
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506 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
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507 | that is successful, unlinking the C<$srcpath>. |
|
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508 | |
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509 | =cut |
|
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510 | |
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511 | sub aio_move($$;$) { |
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512 | my ($src, $dst, $cb) = @_; |
|
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513 | |
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514 | my $pri = aioreq_pri; |
|
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515 | my $grp = aio_group $cb; |
|
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516 | |
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517 | aioreq_pri $pri; |
|
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518 | add $grp aio_rename $src, $dst, sub { |
|
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519 | if ($_[0] && $! == EXDEV) { |
|
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520 | aioreq_pri $pri; |
|
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521 | add $grp aio_copy $src, $dst, sub { |
|
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522 | $grp->result ($_[0]); |
|
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523 | |
|
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524 | if (!$_[0]) { |
|
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525 | aioreq_pri $pri; |
|
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526 | add $grp aio_unlink $src; |
|
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527 | } |
|
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528 | }; |
|
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529 | } else { |
|
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530 | $grp->result ($_[0]); |
|
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531 | } |
|
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532 | }; |
|
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533 | |
|
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534 | $grp |
|
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535 | } |
|
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536 | |
377 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
537 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
378 | |
538 | |
379 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
539 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
380 | separate the entries of directory C<$path> into two sets of names, ones |
540 | efficiently separate the entries of directory C<$path> into two sets of |
381 | you can recurse into (directories or links to them), and ones you cannot |
541 | names, directories you can recurse into (directories), and ones you cannot |
382 | recurse into (everything else). |
542 | recurse into (everything else, including symlinks to directories). |
383 | |
543 | |
384 | C<aio_scandir> is a composite request that creates of many sub requests_ |
544 | C<aio_scandir> is a composite request that creates of many sub requests_ |
385 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
545 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
386 | this function generates. If it is C<< <= 0 >>, then a suitable default |
546 | this function generates. If it is C<< <= 0 >>, then a suitable default |
387 | will be chosen (currently 6). |
547 | will be chosen (currently 4). |
388 | |
548 | |
389 | On error, the callback is called without arguments, otherwise it receives |
549 | On error, the callback is called without arguments, otherwise it receives |
390 | two array-refs with path-relative entry names. |
550 | two array-refs with path-relative entry names. |
391 | |
551 | |
392 | Example: |
552 | Example: |
… | |
… | |
429 | =cut |
589 | =cut |
430 | |
590 | |
431 | sub aio_scandir($$$) { |
591 | sub aio_scandir($$$) { |
432 | my ($path, $maxreq, $cb) = @_; |
592 | my ($path, $maxreq, $cb) = @_; |
433 | |
593 | |
|
|
594 | my $pri = aioreq_pri; |
|
|
595 | |
434 | my $grp = aio_group $cb; |
596 | my $grp = aio_group $cb; |
435 | |
597 | |
436 | $maxreq = 6 if $maxreq <= 0; |
598 | $maxreq = 4 if $maxreq <= 0; |
437 | |
599 | |
438 | # stat once |
600 | # stat once |
|
|
601 | aioreq_pri $pri; |
439 | add $grp aio_stat $path, sub { |
602 | add $grp aio_stat $path, sub { |
440 | return $grp->result () if $_[0]; |
603 | return $grp->result () if $_[0]; |
441 | my $now = time; |
604 | my $now = time; |
442 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
605 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
443 | |
606 | |
444 | # read the directory entries |
607 | # read the directory entries |
|
|
608 | aioreq_pri $pri; |
445 | add $grp aio_readdir $path, sub { |
609 | add $grp aio_readdir $path, sub { |
446 | my $entries = shift |
610 | my $entries = shift |
447 | or return $grp->result (); |
611 | or return $grp->result (); |
448 | |
612 | |
449 | # stat the dir another time |
613 | # stat the dir another time |
|
|
614 | aioreq_pri $pri; |
450 | add $grp aio_stat $path, sub { |
615 | add $grp aio_stat $path, sub { |
451 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
616 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
452 | |
617 | |
453 | my $ndirs; |
618 | my $ndirs; |
454 | |
619 | |
… | |
… | |
469 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
634 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
470 | @$entries]; |
635 | @$entries]; |
471 | |
636 | |
472 | my (@dirs, @nondirs); |
637 | my (@dirs, @nondirs); |
473 | |
638 | |
474 | my ($statcb, $schedcb); |
|
|
475 | my $nreq = 0; |
|
|
476 | |
|
|
477 | my $statgrp = add $grp aio_group; |
639 | my $statgrp = add $grp aio_group sub { |
|
|
640 | $grp->result (\@dirs, \@nondirs); |
|
|
641 | }; |
478 | |
642 | |
479 | $schedcb = sub { |
643 | limit $statgrp $maxreq; |
480 | if (@$entries) { |
644 | feed $statgrp sub { |
481 | if ($nreq < $maxreq) { |
645 | return unless @$entries; |
482 | my $ent = pop @$entries; |
646 | my $entry = pop @$entries; |
|
|
647 | |
|
|
648 | aioreq_pri $pri; |
|
|
649 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
650 | if ($_[0] < 0) { |
|
|
651 | push @nondirs, $entry; |
|
|
652 | } else { |
|
|
653 | # need to check for real directory |
|
|
654 | aioreq_pri $pri; |
|
|
655 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
656 | if (-d _) { |
|
|
657 | push @dirs, $entry; |
|
|
658 | |
|
|
659 | unless (--$ndirs) { |
|
|
660 | push @nondirs, @$entries; |
|
|
661 | feed $statgrp; |
|
|
662 | } |
|
|
663 | } else { |
|
|
664 | push @nondirs, $entry; |
|
|
665 | } |
483 | $nreq++; |
666 | } |
484 | add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
|
|
485 | } |
667 | } |
486 | } elsif (!$nreq) { |
|
|
487 | # finished |
|
|
488 | $statgrp->cancel; |
|
|
489 | undef $statcb; |
|
|
490 | undef $schedcb; |
|
|
491 | $grp->result (\@dirs, \@nondirs); |
|
|
492 | } |
668 | }; |
493 | }; |
669 | }; |
494 | $statcb = sub { |
|
|
495 | my ($status, $entry) = @_; |
|
|
496 | |
|
|
497 | if ($status < 0) { |
|
|
498 | $nreq--; |
|
|
499 | push @nondirs, $entry; |
|
|
500 | &$schedcb; |
|
|
501 | } else { |
|
|
502 | # need to check for real directory |
|
|
503 | add $grp aio_lstat "$path/$entry", sub { |
|
|
504 | $nreq--; |
|
|
505 | |
|
|
506 | if (-d _) { |
|
|
507 | push @dirs, $entry; |
|
|
508 | |
|
|
509 | if (!--$ndirs) { |
|
|
510 | push @nondirs, @$entries; |
|
|
511 | $entries = []; |
|
|
512 | } |
|
|
513 | } else { |
|
|
514 | push @nondirs, $entry; |
|
|
515 | } |
|
|
516 | |
|
|
517 | &$schedcb; |
|
|
518 | } |
|
|
519 | } |
|
|
520 | }; |
|
|
521 | |
|
|
522 | &$schedcb while @$entries && $nreq < $maxreq; |
|
|
523 | }; |
670 | }; |
524 | }; |
671 | }; |
525 | }; |
672 | }; |
526 | |
673 | |
527 | $grp |
674 | $grp |
… | |
… | |
539 | |
686 | |
540 | If this call isn't available because your OS lacks it or it couldn't be |
687 | If this call isn't available because your OS lacks it or it couldn't be |
541 | detected, it will be emulated by calling C<fsync> instead. |
688 | detected, it will be emulated by calling C<fsync> instead. |
542 | |
689 | |
543 | =item aio_group $callback->(...) |
690 | =item aio_group $callback->(...) |
544 | |
|
|
545 | [EXPERIMENTAL] |
|
|
546 | |
691 | |
547 | This is a very special aio request: Instead of doing something, it is a |
692 | This is a very special aio request: Instead of doing something, it is a |
548 | container for other aio requests, which is useful if you want to bundle |
693 | container for other aio requests, which is useful if you want to bundle |
549 | many requests into a single, composite, request with a definite callback |
694 | many requests into a single, composite, request with a definite callback |
550 | and the ability to cancel the whole request with its subrequests. |
695 | and the ability to cancel the whole request with its subrequests. |
… | |
… | |
591 | =head2 IO::AIO::REQ CLASS |
736 | =head2 IO::AIO::REQ CLASS |
592 | |
737 | |
593 | All non-aggregate C<aio_*> functions return an object of this class when |
738 | All non-aggregate C<aio_*> functions return an object of this class when |
594 | called in non-void context. |
739 | called in non-void context. |
595 | |
740 | |
596 | A request always moves through the following five states in its lifetime, |
|
|
597 | in order: B<ready> (request has been created, but has not been executed |
|
|
598 | yet), B<execute> (request is currently being executed), B<pending> |
|
|
599 | (request has been executed but callback has not been called yet), |
|
|
600 | B<result> (results are being processed synchronously, includes calling the |
|
|
601 | callback) and B<done> (request has reached the end of its lifetime and |
|
|
602 | holds no resources anymore). |
|
|
603 | |
|
|
604 | =over 4 |
741 | =over 4 |
605 | |
742 | |
606 | =item cancel $req |
743 | =item cancel $req |
607 | |
744 | |
608 | Cancels the request, if possible. Has the effect of skipping execution |
745 | Cancels the request, if possible. Has the effect of skipping execution |
… | |
… | |
661 | =item * They can also can also be added to other IO::AIO::GRP objects. |
798 | =item * They can also can also be added to other IO::AIO::GRP objects. |
662 | |
799 | |
663 | =item * You must not add requests to a group from within the group callback (or |
800 | =item * You must not add requests to a group from within the group callback (or |
664 | any later time). |
801 | any later time). |
665 | |
802 | |
666 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
667 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
668 | this kind of concurrency-limiting. |
|
|
669 | |
|
|
670 | =back |
803 | =back |
671 | |
804 | |
672 | Their lifetime, simplified, looks like this: when they are empty, they |
805 | Their lifetime, simplified, looks like this: when they are empty, they |
673 | will finish very quickly. If they contain only requests that are in the |
806 | will finish very quickly. If they contain only requests that are in the |
674 | C<done> state, they will also finish. Otherwise they will continue to |
807 | C<done> state, they will also finish. Otherwise they will continue to |
… | |
… | |
689 | be added, including other groups, as long as you do not create circular |
822 | be added, including other groups, as long as you do not create circular |
690 | dependencies. |
823 | dependencies. |
691 | |
824 | |
692 | Returns all its arguments. |
825 | Returns all its arguments. |
693 | |
826 | |
|
|
827 | =item $grp->cancel_subs |
|
|
828 | |
|
|
829 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
830 | itself. Useful when you queued a lot of events but got a result early. |
|
|
831 | |
694 | =item $grp->result (...) |
832 | =item $grp->result (...) |
695 | |
833 | |
696 | Set the result value(s) that will be passed to the group callback when all |
834 | Set the result value(s) that will be passed to the group callback when all |
697 | subrequests have finished. By default, no argument will be passed. |
835 | subrequests have finished and set thre groups errno to the current value |
|
|
836 | of errno (just like calling C<errno> without an error number). By default, |
|
|
837 | no argument will be passed and errno is zero. |
|
|
838 | |
|
|
839 | =item $grp->errno ([$errno]) |
|
|
840 | |
|
|
841 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
842 | when the argument is missing. |
|
|
843 | |
|
|
844 | Every aio request has an associated errno value that is restored when |
|
|
845 | the callback is invoked. This method lets you change this value from its |
|
|
846 | default (0). |
|
|
847 | |
|
|
848 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
849 | before the call to C<result>, or call c<errno> after it. |
698 | |
850 | |
699 | =item feed $grp $callback->($grp) |
851 | =item feed $grp $callback->($grp) |
700 | |
|
|
701 | [VERY EXPERIMENTAL] |
|
|
702 | |
852 | |
703 | Sets a feeder/generator on this group: every group can have an attached |
853 | Sets a feeder/generator on this group: every group can have an attached |
704 | generator that generates requests if idle. The idea behind this is that, |
854 | generator that generates requests if idle. The idea behind this is that, |
705 | although you could just queue as many requests as you want in a group, |
855 | although you could just queue as many requests as you want in a group, |
706 | this might starve other requests for a potentially long time. For |
856 | this might starve other requests for a potentially long time. For |
… | |
… | |
743 | |
893 | |
744 | =back |
894 | =back |
745 | |
895 | |
746 | =head2 SUPPORT FUNCTIONS |
896 | =head2 SUPPORT FUNCTIONS |
747 | |
897 | |
|
|
898 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
899 | |
748 | =over 4 |
900 | =over 4 |
749 | |
901 | |
750 | =item $fileno = IO::AIO::poll_fileno |
902 | =item $fileno = IO::AIO::poll_fileno |
751 | |
903 | |
752 | Return the I<request result pipe file descriptor>. This filehandle must be |
904 | Return the I<request result pipe file descriptor>. This filehandle must be |
… | |
… | |
756 | |
908 | |
757 | See C<poll_cb> for an example. |
909 | See C<poll_cb> for an example. |
758 | |
910 | |
759 | =item IO::AIO::poll_cb |
911 | =item IO::AIO::poll_cb |
760 | |
912 | |
761 | Process all outstanding events on the result pipe. You have to call this |
913 | Process some outstanding events on the result pipe. You have to call this |
762 | regularly. Returns the number of events processed. Returns immediately |
914 | regularly. Returns the number of events processed. Returns immediately |
763 | when no events are outstanding. |
915 | when no events are outstanding. The amount of events processed depends on |
|
|
916 | the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. |
|
|
917 | |
|
|
918 | If not all requests were processed for whatever reason, the filehandle |
|
|
919 | will still be ready when C<poll_cb> returns. |
764 | |
920 | |
765 | Example: Install an Event watcher that automatically calls |
921 | Example: Install an Event watcher that automatically calls |
766 | IO::AIO::poll_cb with high priority: |
922 | IO::AIO::poll_cb with high priority: |
767 | |
923 | |
768 | Event->io (fd => IO::AIO::poll_fileno, |
924 | Event->io (fd => IO::AIO::poll_fileno, |
769 | poll => 'r', async => 1, |
925 | poll => 'r', async => 1, |
770 | cb => \&IO::AIO::poll_cb); |
926 | cb => \&IO::AIO::poll_cb); |
771 | |
927 | |
|
|
928 | =item IO::AIO::max_poll_reqs $nreqs |
|
|
929 | |
|
|
930 | =item IO::AIO::max_poll_time $seconds |
|
|
931 | |
|
|
932 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
933 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
934 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
935 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
936 | of time C<poll_cb> is allowed to use). |
|
|
937 | |
|
|
938 | Setting these is useful if you want to ensure some level of |
|
|
939 | interactiveness when perl is not fast enough to process all requests in |
|
|
940 | time. |
|
|
941 | |
|
|
942 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
|
|
943 | |
|
|
944 | Example: Install an Event watcher that automatically calls |
|
|
945 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
|
|
946 | program get the CPU sometimes even under high AIO load. |
|
|
947 | |
|
|
948 | # try not to spend much more than 0.1s in poll_cb |
|
|
949 | IO::AIO::max_poll_time 0.1; |
|
|
950 | |
|
|
951 | # use a low priority so other tasks have priority |
|
|
952 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
953 | poll => 'r', nice => 1, |
|
|
954 | cb => &IO::AIO::poll_cb); |
|
|
955 | |
772 | =item IO::AIO::poll_wait |
956 | =item IO::AIO::poll_wait |
773 | |
957 | |
774 | Wait till the result filehandle becomes ready for reading (simply does a |
958 | Wait till the result filehandle becomes ready for reading (simply does a |
775 | C<select> on the filehandle. This is useful if you want to synchronously wait |
959 | C<select> on the filehandle. This is useful if you want to synchronously |
776 | for some requests to finish). |
960 | wait for some requests to finish). |
777 | |
961 | |
778 | See C<nreqs> for an example. |
962 | See C<nreqs> for an example. |
779 | |
963 | |
|
|
964 | =item IO::AIO::poll |
|
|
965 | |
|
|
966 | Waits until some requests have been handled. |
|
|
967 | |
|
|
968 | Strictly equivalent to: |
|
|
969 | |
|
|
970 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
971 | if IO::AIO::nreqs; |
|
|
972 | |
780 | =item IO::AIO::nreqs |
973 | =item IO::AIO::flush |
781 | |
974 | |
782 | Returns the number of requests currently outstanding (i.e. for which their |
975 | Wait till all outstanding AIO requests have been handled. |
783 | callback has not been invoked yet). |
|
|
784 | |
976 | |
785 | Example: wait till there are no outstanding requests anymore: |
977 | Strictly equivalent to: |
786 | |
978 | |
787 | IO::AIO::poll_wait, IO::AIO::poll_cb |
979 | IO::AIO::poll_wait, IO::AIO::poll_cb |
788 | while IO::AIO::nreqs; |
980 | while IO::AIO::nreqs; |
789 | |
981 | |
790 | =item IO::AIO::flush |
982 | =head3 CONTROLLING THE NUMBER OF THREADS |
791 | |
|
|
792 | Wait till all outstanding AIO requests have been handled. |
|
|
793 | |
|
|
794 | Strictly equivalent to: |
|
|
795 | |
|
|
796 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
797 | while IO::AIO::nreqs; |
|
|
798 | |
|
|
799 | =item IO::AIO::poll |
|
|
800 | |
|
|
801 | Waits until some requests have been handled. |
|
|
802 | |
|
|
803 | Strictly equivalent to: |
|
|
804 | |
|
|
805 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
806 | if IO::AIO::nreqs; |
|
|
807 | |
983 | |
808 | =item IO::AIO::min_parallel $nthreads |
984 | =item IO::AIO::min_parallel $nthreads |
809 | |
985 | |
810 | Set the minimum number of AIO threads to C<$nthreads>. The current |
986 | Set the minimum number of AIO threads to C<$nthreads>. The current |
811 | default is C<8>, which means eight asynchronous operations can execute |
987 | default is C<8>, which means eight asynchronous operations can execute |
812 | concurrently at any one time (the number of outstanding requests, |
988 | concurrently at any one time (the number of outstanding requests, |
813 | however, is unlimited). |
989 | however, is unlimited). |
814 | |
990 | |
815 | IO::AIO starts threads only on demand, when an AIO request is queued and |
991 | IO::AIO starts threads only on demand, when an AIO request is queued and |
816 | no free thread exists. |
992 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
993 | create demand for a hundred threads, even if it turns out that everything |
|
|
994 | is in the cache and could have been processed faster by a single thread. |
817 | |
995 | |
818 | It is recommended to keep the number of threads relatively low, as some |
996 | It is recommended to keep the number of threads relatively low, as some |
819 | Linux kernel versions will scale negatively with the number of threads |
997 | Linux kernel versions will scale negatively with the number of threads |
820 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
998 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
821 | versions, 4-32 threads should be fine. |
999 | versions, 4-32 threads should be fine. |
… | |
… | |
835 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1013 | This module automatically runs C<max_parallel 0> at program end, to ensure |
836 | that all threads are killed and that there are no outstanding requests. |
1014 | that all threads are killed and that there are no outstanding requests. |
837 | |
1015 | |
838 | Under normal circumstances you don't need to call this function. |
1016 | Under normal circumstances you don't need to call this function. |
839 | |
1017 | |
|
|
1018 | =item IO::AIO::max_idle $nthreads |
|
|
1019 | |
|
|
1020 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
|
|
1021 | threads that did not get a request to process within 10 seconds). That |
|
|
1022 | means if a thread becomes idle while C<$nthreads> other threads are also |
|
|
1023 | idle, it will free its resources and exit. |
|
|
1024 | |
|
|
1025 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1026 | to allow for extremely high load situations, but want to free resources |
|
|
1027 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1028 | |
|
|
1029 | The default is probably ok in most situations, especially if thread |
|
|
1030 | creation is fast. If thread creation is very slow on your system you might |
|
|
1031 | want to use larger values. |
|
|
1032 | |
840 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
1033 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
841 | |
1034 | |
842 | [DEPRECATED] |
1035 | This is a very bad function to use in interactive programs because it |
|
|
1036 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1037 | use an C<aio_group> together with a feed callback. |
843 | |
1038 | |
844 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1039 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
845 | try to queue up more than this number of requests, the caller will block until |
1040 | to queue up more than this number of requests, the next call to the |
846 | some requests have been handled. |
1041 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
1042 | function will block until the limit is no longer exceeded. |
847 | |
1043 | |
848 | The default is very large, so normally there is no practical limit. If you |
1044 | The default value is very large, so there is no practical limit on the |
849 | queue up many requests in a loop it often improves speed if you set |
1045 | number of outstanding requests. |
850 | this to a relatively low number, such as C<100>. |
|
|
851 | |
1046 | |
852 | This function does not work well together with C<aio_group>'s, and their |
1047 | You can still queue as many requests as you want. Therefore, |
853 | feeder interface is better suited to limiting concurrency, so do not use |
1048 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
854 | this function. |
1049 | as a stop gap to shield against fatal memory overflow (with large values). |
855 | |
1050 | |
856 | Under normal circumstances you don't need to call this function. |
1051 | =head3 STATISTICAL INFORMATION |
|
|
1052 | |
|
|
1053 | =item IO::AIO::nreqs |
|
|
1054 | |
|
|
1055 | Returns the number of requests currently in the ready, execute or pending |
|
|
1056 | states (i.e. for which their callback has not been invoked yet). |
|
|
1057 | |
|
|
1058 | Example: wait till there are no outstanding requests anymore: |
|
|
1059 | |
|
|
1060 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1061 | while IO::AIO::nreqs; |
|
|
1062 | |
|
|
1063 | =item IO::AIO::nready |
|
|
1064 | |
|
|
1065 | Returns the number of requests currently in the ready state (not yet |
|
|
1066 | executed). |
|
|
1067 | |
|
|
1068 | =item IO::AIO::npending |
|
|
1069 | |
|
|
1070 | Returns the number of requests currently in the pending state (executed, |
|
|
1071 | but not yet processed by poll_cb). |
857 | |
1072 | |
858 | =back |
1073 | =back |
859 | |
1074 | |
860 | =cut |
1075 | =cut |
861 | |
1076 | |
… | |
… | |
876 | } |
1091 | } |
877 | |
1092 | |
878 | min_parallel 8; |
1093 | min_parallel 8; |
879 | |
1094 | |
880 | END { |
1095 | END { |
881 | max_parallel 0; |
1096 | min_parallel 1; |
882 | } |
1097 | flush; |
|
|
1098 | }; |
883 | |
1099 | |
884 | 1; |
1100 | 1; |
885 | |
1101 | |
886 | =head2 FORK BEHAVIOUR |
1102 | =head2 FORK BEHAVIOUR |
887 | |
1103 | |
888 | This module should do "the right thing" when the process using it forks: |
1104 | This module should do "the right thing" when the process using it forks: |
889 | |
1105 | |
890 | Before the fork, IO::AIO enters a quiescent state where no requests |
1106 | Before the fork, IO::AIO enters a quiescent state where no requests |
891 | can be added in other threads and no results will be processed. After |
1107 | can be added in other threads and no results will be processed. After |
892 | the fork the parent simply leaves the quiescent state and continues |
1108 | the fork the parent simply leaves the quiescent state and continues |
893 | request/result processing, while the child clears the request/result |
1109 | request/result processing, while the child frees the request/result queue |
894 | queue (so the requests started before the fork will only be handled in |
1110 | (so that the requests started before the fork will only be handled in the |
895 | the parent). Threads will be started on demand until the limit ste in the |
1111 | parent). Threads will be started on demand until the limit set in the |
896 | parent process has been reached again. |
1112 | parent process has been reached again. |
897 | |
1113 | |
898 | In short: the parent will, after a short pause, continue as if fork had |
1114 | In short: the parent will, after a short pause, continue as if fork had |
899 | not been called, while the child will act as if IO::AIO has not been used |
1115 | not been called, while the child will act as if IO::AIO has not been used |
900 | yet. |
1116 | yet. |
901 | |
1117 | |
902 | =head2 MEMORY USAGE |
1118 | =head2 MEMORY USAGE |
903 | |
1119 | |
|
|
1120 | Per-request usage: |
|
|
1121 | |
904 | Each aio request uses - depending on your architecture - around 128 bytes |
1122 | Each aio request uses - depending on your architecture - around 100-200 |
905 | of memory. In addition, stat requests need a stat buffer (possibly a few |
1123 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
906 | hundred bytes). Perl scalars and other data passed into aio requests will |
1124 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
907 | also be locked. |
1125 | scalars and other data passed into aio requests will also be locked and |
|
|
1126 | will consume memory till the request has entered the done state. |
908 | |
1127 | |
909 | This is now awfully much, so queuing lots of requests is not usually a |
1128 | This is now awfully much, so queuing lots of requests is not usually a |
910 | problem. |
1129 | problem. |
911 | |
1130 | |
912 | Each thread needs a stack area which is usually around 16k, sometimes much |
1131 | Per-thread usage: |
913 | larger, depending on the OS. |
1132 | |
|
|
1133 | In the execution phase, some aio requests require more memory for |
|
|
1134 | temporary buffers, and each thread requires a stack and other data |
|
|
1135 | structures (usually around 16k-128k, depending on the OS). |
|
|
1136 | |
|
|
1137 | =head1 KNOWN BUGS |
|
|
1138 | |
|
|
1139 | Known bugs will be fixed in the next release. |
914 | |
1140 | |
915 | =head1 SEE ALSO |
1141 | =head1 SEE ALSO |
916 | |
1142 | |
917 | L<Coro::AIO>. |
1143 | L<Coro::AIO>. |
918 | |
1144 | |