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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 most of this works on all types of file descriptors (for example |
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67 | sockets), using these functions on file descriptors that support |
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68 | nonblocking operation (again, sockets, pipes etc.) is very inefficient or |
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69 | might not work (aio_read fails on sockets/pipes/fifos). Use an event loop |
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70 | for that (such as the L<Event|Event> module): IO::AIO will naturally fit |
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71 | into such an event loop itself. |
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72 | |
56 | Currently, a number of threads are started that execute your read/writes |
73 | 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 |
74 | 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 |
75 | 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 |
76 | 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 |
77 | functions available on many operating systems. However, they are often |
61 | (Linux doesn't allow them on normal files currently, for example), |
78 | 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 |
79 | files currently, for example), and they would only support aio_read and |
63 | functionality would have to be implemented using threads anyway. |
80 | aio_write, so the remaining functionality would have to be implemented |
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81 | using threads anyway. |
64 | |
82 | |
65 | Although the module will work with in the presence of other threads, |
83 | 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 |
84 | 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 |
85 | locking yourself, always call C<poll_cb> from within the same thread, or |
68 | call C<poll_cb> (or other C<aio_> functions) recursively. |
86 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
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87 | |
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88 | =head2 EXAMPLE |
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89 | |
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90 | This is a simple example that uses the Event module and loads |
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91 | F</etc/passwd> asynchronously: |
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92 | |
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93 | use Fcntl; |
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94 | use Event; |
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95 | use IO::AIO; |
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96 | |
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97 | # register the IO::AIO callback with Event |
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98 | Event->io (fd => IO::AIO::poll_fileno, |
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99 | poll => 'r', |
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100 | cb => \&IO::AIO::poll_cb); |
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101 | |
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102 | # queue the request to open /etc/passwd |
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103 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
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104 | my $fh = $_[0] |
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105 | or die "error while opening: $!"; |
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106 | |
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107 | # stat'ing filehandles is generally non-blocking |
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108 | my $size = -s $fh; |
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109 | |
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110 | # queue a request to read the file |
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111 | my $contents; |
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112 | aio_read $fh, 0, $size, $contents, 0, sub { |
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113 | $_[0] == $size |
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114 | or die "short read: $!"; |
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115 | |
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116 | close $fh; |
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117 | |
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118 | # file contents now in $contents |
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119 | print $contents; |
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120 | |
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121 | # exit event loop and program |
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122 | Event::unloop; |
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123 | }; |
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124 | }; |
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125 | |
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126 | # possibly queue up other requests, or open GUI windows, |
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127 | # check for sockets etc. etc. |
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128 | |
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129 | # process events as long as there are some: |
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130 | Event::loop; |
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131 | |
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132 | =head1 REQUEST ANATOMY AND LIFETIME |
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133 | |
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134 | Every C<aio_*> function creates a request. which is a C data structure not |
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135 | directly visible to Perl. |
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136 | |
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137 | If called in non-void context, every request function returns a Perl |
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138 | object representing the request. In void context, nothing is returned, |
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139 | which saves a bit of memory. |
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140 | |
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141 | The perl object is a fairly standard ref-to-hash object. The hash contents |
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142 | are not used by IO::AIO so you are free to store anything you like in it. |
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143 | |
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144 | During their existance, aio requests travel through the following states, |
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145 | in order: |
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146 | |
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147 | =over 4 |
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148 | |
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149 | =item ready |
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150 | |
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151 | Immediately after a request is created it is put into the ready state, |
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152 | waiting for a thread to execute it. |
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153 | |
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154 | =item execute |
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155 | |
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156 | A thread has accepted the request for processing and is currently |
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157 | executing it (e.g. blocking in read). |
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158 | |
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159 | =item pending |
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160 | |
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161 | The request has been executed and is waiting for result processing. |
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162 | |
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163 | While request submission and execution is fully asynchronous, result |
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164 | processing is not and relies on the perl interpreter calling C<poll_cb> |
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165 | (or another function with the same effect). |
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166 | |
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167 | =item result |
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168 | |
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169 | The request results are processed synchronously by C<poll_cb>. |
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170 | |
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171 | The C<poll_cb> function will process all outstanding aio requests by |
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172 | calling their callbacks, freeing memory associated with them and managing |
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173 | any groups they are contained in. |
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174 | |
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175 | =item done |
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176 | |
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177 | Request has reached the end of its lifetime and holds no resources anymore |
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178 | (except possibly for the Perl object, but its connection to the actual |
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179 | aio request is severed and calling its methods will either do nothing or |
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180 | result in a runtime error). |
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181 | |
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182 | =back |
69 | |
183 | |
70 | =cut |
184 | =cut |
71 | |
185 | |
72 | package IO::AIO; |
186 | package IO::AIO; |
73 | |
187 | |
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75 | use strict 'vars'; |
189 | use strict 'vars'; |
76 | |
190 | |
77 | use base 'Exporter'; |
191 | use base 'Exporter'; |
78 | |
192 | |
79 | BEGIN { |
193 | BEGIN { |
80 | our $VERSION = '2.0'; |
194 | our $VERSION = '2.2'; |
81 | |
195 | |
82 | our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
196 | 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 |
197 | 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 |
198 | aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link |
85 | aio_group aio_nop); |
199 | aio_move aio_copy aio_group aio_nop aio_mknod); |
86 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri)); |
200 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
87 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
201 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
88 | min_parallel max_parallel max_outstanding nreqs); |
202 | min_parallel max_parallel max_idle |
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203 | nreqs nready npending nthreads |
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204 | max_poll_time max_poll_reqs); |
89 | |
205 | |
90 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
206 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
91 | |
207 | |
92 | require XSLoader; |
208 | require XSLoader; |
93 | XSLoader::load ("IO::AIO", $VERSION); |
209 | XSLoader::load ("IO::AIO", $VERSION); |
94 | } |
210 | } |
95 | |
211 | |
96 | =head1 FUNCTIONS |
212 | =head1 FUNCTIONS |
97 | |
213 | |
98 | =head2 AIO FUNCTIONS |
214 | =head2 AIO REQUEST FUNCTIONS |
99 | |
215 | |
100 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
216 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
101 | with the same name (sans C<aio_>). The arguments are similar or identical, |
217 | with the same name (sans C<aio_>). The arguments are similar or identical, |
102 | and they all accept an additional (and optional) C<$callback> argument |
218 | 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 |
219 | which must be a code reference. This code reference will get called with |
… | |
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106 | syscall has been executed asynchronously. |
222 | syscall has been executed asynchronously. |
107 | |
223 | |
108 | All functions expecting a filehandle keep a copy of the filehandle |
224 | All functions expecting a filehandle keep a copy of the filehandle |
109 | internally until the request has finished. |
225 | internally until the request has finished. |
110 | |
226 | |
111 | All requests return objects of type L<IO::AIO::REQ> that allow further |
227 | All functions return request objects of type L<IO::AIO::REQ> that allow |
112 | manipulation of those requests while they are in-flight. |
228 | further manipulation of those requests while they are in-flight. |
113 | |
229 | |
114 | The pathnames you pass to these routines I<must> be absolute and |
230 | 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 |
231 | 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 |
232 | request is being executed, the current working directory could have |
117 | changed. Alternatively, you can make sure that you never change the |
233 | changed. Alternatively, you can make sure that you never change the |
118 | current working directory. |
234 | current working directory anywhere in the program and then use relative |
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235 | paths. |
119 | |
236 | |
120 | To encode pathnames to byte form, either make sure you either: a) |
237 | 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 |
238 | 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 |
239 | 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 |
240 | 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) |
241 | environment, d) use Glib::filename_from_unicode on unicode filenames or e) |
125 | use something else. |
242 | use something else to ensure your scalar has the correct contents. |
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243 | |
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244 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
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245 | handles correctly wether it is set or not. |
126 | |
246 | |
127 | =over 4 |
247 | =over 4 |
128 | |
248 | |
129 | =item aioreq_pri $pri |
249 | =item $prev_pri = aioreq_pri [$pri] |
130 | |
250 | |
131 | Sets the priority for the next aio request. The default priority |
251 | Returns the priority value that would be used for the next request and, if |
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252 | C<$pri> is given, sets the priority for the next aio request. |
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253 | |
132 | is C<0>, the minimum and maximum priorities are C<-4> and C<4>, |
254 | The default priority is C<0>, the minimum and maximum priorities are C<-4> |
133 | respectively. Requests with higher priority will be serviced first. |
255 | and C<4>, respectively. Requests with higher priority will be serviced |
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256 | first. |
134 | |
257 | |
135 | The priority will be reset to C<0> after each call to one of the C<aio_> |
258 | The priority will be reset to C<0> after each call to one of the C<aio_*> |
136 | functions. |
259 | functions. |
137 | |
260 | |
138 | Example: open a file with low priority, then read something from it with |
261 | 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 |
262 | higher priority so the read request is serviced before other low priority |
140 | open requests (potentially spamming the cache): |
263 | open requests (potentially spamming the cache): |
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150 | }; |
273 | }; |
151 | |
274 | |
152 | =item aioreq_nice $pri_adjust |
275 | =item aioreq_nice $pri_adjust |
153 | |
276 | |
154 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
277 | Similar to C<aioreq_pri>, but subtracts the given value from the current |
155 | priority, so effects are cumulative. |
278 | priority, so the effect is cumulative. |
156 | |
279 | |
157 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
280 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
158 | |
281 | |
159 | Asynchronously open or create a file and call the callback with a newly |
282 | Asynchronously open or create a file and call the callback with a newly |
160 | created filehandle for the file. |
283 | created filehandle for the file. |
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210 | |
333 | |
211 | aio_read $fh, 7, 15, $buffer, 0, sub { |
334 | aio_read $fh, 7, 15, $buffer, 0, sub { |
212 | $_[0] > 0 or die "read error: $!"; |
335 | $_[0] > 0 or die "read error: $!"; |
213 | print "read $_[0] bytes: <$buffer>\n"; |
336 | print "read $_[0] bytes: <$buffer>\n"; |
214 | }; |
337 | }; |
215 | |
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216 | =item aio_move $srcpath, $dstpath, $callback->($status) |
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217 | |
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218 | [EXPERIMENTAL due to internal aio_group use] |
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219 | |
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220 | Try to move the I<file> (directories not supported as either source or |
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221 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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222 | the C<0> (error) or C<-1> ok. |
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223 | |
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224 | This is a composite request that tries to rename(2) the file first. If |
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225 | rename files with C<EXDEV>, it creates the destination file with mode 0200 |
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226 | and copies the contents of the source file into it using C<aio_sendfile>, |
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227 | followed by restoring atime, mtime, access mode and uid/gid, in that |
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228 | order, and unlinking the C<$srcpath>. |
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229 | |
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230 | If an error occurs, the partial destination file will be unlinked, if |
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231 | possible, except when setting atime, mtime, access mode and uid/gid, where |
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232 | errors are being ignored. |
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233 | |
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234 | =cut |
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235 | |
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236 | sub aio_move($$$) { |
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237 | my ($src, $dst, $cb) = @_; |
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238 | |
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239 | my $grp = aio_group $cb; |
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240 | |
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241 | add $grp aio_rename $src, $dst, sub { |
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242 | if ($_[0] && $! == EXDEV) { |
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243 | add $grp aio_open $src, O_RDONLY, 0, sub { |
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244 | if (my $src_fh = $_[0]) { |
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245 | my @stat = stat $src_fh; |
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246 | |
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247 | add $grp aio_open $dst, O_WRONLY, 0200, sub { |
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248 | if (my $dst_fh = $_[0]) { |
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249 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
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250 | close $src_fh; |
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251 | |
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252 | if ($_[0] == $stat[7]) { |
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253 | utime $stat[8], $stat[9], $dst; |
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254 | chmod $stat[2] & 07777, $dst_fh; |
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255 | chown $stat[4], $stat[5], $dst_fh; |
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256 | close $dst_fh; |
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257 | |
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258 | add $grp aio_unlink $src, sub { |
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259 | $grp->result ($_[0]); |
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260 | }; |
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261 | } else { |
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262 | my $errno = $!; |
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263 | add $grp aio_unlink $dst, sub { |
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264 | $! = $errno; |
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265 | $grp->result (-1); |
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266 | }; |
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267 | } |
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268 | }; |
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269 | } else { |
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270 | $grp->result (-1); |
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271 | } |
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272 | }, |
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273 | |
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274 | } else { |
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275 | $grp->result (-1); |
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276 | } |
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277 | }; |
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278 | } else { |
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279 | $grp->result ($_[0]); |
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280 | } |
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281 | }; |
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282 | |
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283 | $grp |
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284 | } |
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285 | |
338 | |
286 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
339 | =item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) |
287 | |
340 | |
288 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
341 | Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts |
289 | reading at byte offset C<$in_offset>, and starts writing at the current |
342 | reading at byte offset C<$in_offset>, and starts writing at the current |
… | |
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345 | =item aio_unlink $pathname, $callback->($status) |
398 | =item aio_unlink $pathname, $callback->($status) |
346 | |
399 | |
347 | Asynchronously unlink (delete) a file and call the callback with the |
400 | Asynchronously unlink (delete) a file and call the callback with the |
348 | result code. |
401 | result code. |
349 | |
402 | |
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403 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
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404 | |
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405 | [EXPERIMENTAL] |
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406 | |
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407 | Asynchronously create a device node (or fifo). See mknod(2). |
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408 | |
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409 | The only (POSIX-) portable way of calling this function is: |
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410 | |
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411 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
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412 | |
350 | =item aio_link $srcpath, $dstpath, $callback->($status) |
413 | =item aio_link $srcpath, $dstpath, $callback->($status) |
351 | |
414 | |
352 | Asynchronously create a new link to the existing object at C<$srcpath> at |
415 | Asynchronously create a new link to the existing object at C<$srcpath> at |
353 | the path C<$dstpath> and call the callback with the result code. |
416 | the path C<$dstpath> and call the callback with the result code. |
354 | |
417 | |
355 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
418 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
356 | |
419 | |
357 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
420 | Asynchronously create a new symbolic link to the existing object at C<$srcpath> at |
358 | the path C<$dstpath> and call the callback with the result code. |
421 | the path C<$dstpath> and call the callback with the result code. |
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422 | |
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423 | =item aio_readlink $path, $callback->($link) |
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424 | |
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425 | Asynchronously read the symlink specified by C<$path> and pass it to |
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426 | the callback. If an error occurs, nothing or undef gets passed to the |
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427 | callback. |
359 | |
428 | |
360 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
429 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
361 | |
430 | |
362 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
431 | Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as |
363 | rename(2) and call the callback with the result code. |
432 | rename(2) and call the callback with the result code. |
… | |
… | |
374 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
443 | sorted, and will B<NOT> include the C<.> and C<..> entries. |
375 | |
444 | |
376 | The callback a single argument which is either C<undef> or an array-ref |
445 | The callback a single argument which is either C<undef> or an array-ref |
377 | with the filenames. |
446 | with the filenames. |
378 | |
447 | |
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448 | =item aio_copy $srcpath, $dstpath, $callback->($status) |
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449 | |
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450 | Try to copy the I<file> (directories not supported as either source or |
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451 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
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452 | the C<0> (error) or C<-1> ok. |
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453 | |
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454 | This is a composite request that it creates the destination file with |
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455 | mode 0200 and copies the contents of the source file into it using |
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456 | C<aio_sendfile>, followed by restoring atime, mtime, access mode and |
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457 | uid/gid, in that order. |
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458 | |
|
|
459 | If an error occurs, the partial destination file will be unlinked, if |
|
|
460 | possible, except when setting atime, mtime, access mode and uid/gid, where |
|
|
461 | errors are being ignored. |
|
|
462 | |
|
|
463 | =cut |
|
|
464 | |
|
|
465 | sub aio_copy($$;$) { |
|
|
466 | my ($src, $dst, $cb) = @_; |
|
|
467 | |
|
|
468 | my $pri = aioreq_pri; |
|
|
469 | my $grp = aio_group $cb; |
|
|
470 | |
|
|
471 | aioreq_pri $pri; |
|
|
472 | add $grp aio_open $src, O_RDONLY, 0, sub { |
|
|
473 | if (my $src_fh = $_[0]) { |
|
|
474 | my @stat = stat $src_fh; |
|
|
475 | |
|
|
476 | aioreq_pri $pri; |
|
|
477 | add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { |
|
|
478 | if (my $dst_fh = $_[0]) { |
|
|
479 | aioreq_pri $pri; |
|
|
480 | add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { |
|
|
481 | if ($_[0] == $stat[7]) { |
|
|
482 | $grp->result (0); |
|
|
483 | close $src_fh; |
|
|
484 | |
|
|
485 | # those should not normally block. should. should. |
|
|
486 | utime $stat[8], $stat[9], $dst; |
|
|
487 | chmod $stat[2] & 07777, $dst_fh; |
|
|
488 | chown $stat[4], $stat[5], $dst_fh; |
|
|
489 | close $dst_fh; |
|
|
490 | } else { |
|
|
491 | $grp->result (-1); |
|
|
492 | close $src_fh; |
|
|
493 | close $dst_fh; |
|
|
494 | |
|
|
495 | aioreq $pri; |
|
|
496 | add $grp aio_unlink $dst; |
|
|
497 | } |
|
|
498 | }; |
|
|
499 | } else { |
|
|
500 | $grp->result (-1); |
|
|
501 | } |
|
|
502 | }, |
|
|
503 | |
|
|
504 | } else { |
|
|
505 | $grp->result (-1); |
|
|
506 | } |
|
|
507 | }; |
|
|
508 | |
|
|
509 | $grp |
|
|
510 | } |
|
|
511 | |
|
|
512 | =item aio_move $srcpath, $dstpath, $callback->($status) |
|
|
513 | |
|
|
514 | Try to move the I<file> (directories not supported as either source or |
|
|
515 | destination) from C<$srcpath> to C<$dstpath> and call the callback with |
|
|
516 | the C<0> (error) or C<-1> ok. |
|
|
517 | |
|
|
518 | This is a composite request that tries to rename(2) the file first. If |
|
|
519 | rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if |
|
|
520 | that is successful, unlinking the C<$srcpath>. |
|
|
521 | |
|
|
522 | =cut |
|
|
523 | |
|
|
524 | sub aio_move($$;$) { |
|
|
525 | my ($src, $dst, $cb) = @_; |
|
|
526 | |
|
|
527 | my $pri = aioreq_pri; |
|
|
528 | my $grp = aio_group $cb; |
|
|
529 | |
|
|
530 | aioreq_pri $pri; |
|
|
531 | add $grp aio_rename $src, $dst, sub { |
|
|
532 | if ($_[0] && $! == EXDEV) { |
|
|
533 | aioreq_pri $pri; |
|
|
534 | add $grp aio_copy $src, $dst, sub { |
|
|
535 | $grp->result ($_[0]); |
|
|
536 | |
|
|
537 | if (!$_[0]) { |
|
|
538 | aioreq_pri $pri; |
|
|
539 | add $grp aio_unlink $src; |
|
|
540 | } |
|
|
541 | }; |
|
|
542 | } else { |
|
|
543 | $grp->result ($_[0]); |
|
|
544 | } |
|
|
545 | }; |
|
|
546 | |
|
|
547 | $grp |
|
|
548 | } |
|
|
549 | |
379 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
550 | =item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) |
380 | |
551 | |
381 | [EXPERIMENTAL due to internal aio_group use] |
|
|
382 | |
|
|
383 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
552 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
384 | separate the entries of directory C<$path> into two sets of names, ones |
553 | efficiently separate the entries of directory C<$path> into two sets of |
385 | you can recurse into (directories or links to them), and ones you cannot |
554 | names, directories you can recurse into (directories), and ones you cannot |
386 | recurse into (everything else). |
555 | recurse into (everything else, including symlinks to directories). |
387 | |
556 | |
388 | C<aio_scandir> is a composite request that creates of many sub requests_ |
557 | C<aio_scandir> is a composite request that creates of many sub requests_ |
389 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
558 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
390 | this function generates. If it is C<< <= 0 >>, then a suitable default |
559 | this function generates. If it is C<< <= 0 >>, then a suitable default |
391 | will be chosen (currently 6). |
560 | will be chosen (currently 4). |
392 | |
561 | |
393 | On error, the callback is called without arguments, otherwise it receives |
562 | On error, the callback is called without arguments, otherwise it receives |
394 | two array-refs with path-relative entry names. |
563 | two array-refs with path-relative entry names. |
395 | |
564 | |
396 | Example: |
565 | Example: |
… | |
… | |
433 | =cut |
602 | =cut |
434 | |
603 | |
435 | sub aio_scandir($$$) { |
604 | sub aio_scandir($$$) { |
436 | my ($path, $maxreq, $cb) = @_; |
605 | my ($path, $maxreq, $cb) = @_; |
437 | |
606 | |
|
|
607 | my $pri = aioreq_pri; |
|
|
608 | |
438 | my $grp = aio_group $cb; |
609 | my $grp = aio_group $cb; |
439 | |
610 | |
440 | $maxreq = 6 if $maxreq <= 0; |
611 | $maxreq = 4 if $maxreq <= 0; |
441 | |
612 | |
442 | # stat once |
613 | # stat once |
|
|
614 | aioreq_pri $pri; |
443 | add $grp aio_stat $path, sub { |
615 | add $grp aio_stat $path, sub { |
444 | return $grp->result () if $_[0]; |
616 | return $grp->result () if $_[0]; |
445 | my $now = time; |
617 | my $now = time; |
446 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
618 | my $hash1 = join ":", (stat _)[0,1,3,7,9]; |
447 | |
619 | |
448 | # read the directory entries |
620 | # read the directory entries |
|
|
621 | aioreq_pri $pri; |
449 | add $grp aio_readdir $path, sub { |
622 | add $grp aio_readdir $path, sub { |
450 | my $entries = shift |
623 | my $entries = shift |
451 | or return $grp->result (); |
624 | or return $grp->result (); |
452 | |
625 | |
453 | # stat the dir another time |
626 | # stat the dir another time |
|
|
627 | aioreq_pri $pri; |
454 | add $grp aio_stat $path, sub { |
628 | add $grp aio_stat $path, sub { |
455 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
629 | my $hash2 = join ":", (stat _)[0,1,3,7,9]; |
456 | |
630 | |
457 | my $ndirs; |
631 | my $ndirs; |
458 | |
632 | |
… | |
… | |
473 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
647 | map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], |
474 | @$entries]; |
648 | @$entries]; |
475 | |
649 | |
476 | my (@dirs, @nondirs); |
650 | my (@dirs, @nondirs); |
477 | |
651 | |
478 | my ($statcb, $schedcb); |
|
|
479 | my $nreq = 0; |
|
|
480 | |
|
|
481 | my $statgrp = add $grp aio_group; |
652 | my $statgrp = add $grp aio_group sub { |
|
|
653 | $grp->result (\@dirs, \@nondirs); |
|
|
654 | }; |
482 | |
655 | |
483 | $schedcb = sub { |
656 | limit $statgrp $maxreq; |
484 | if (@$entries) { |
657 | feed $statgrp sub { |
485 | if ($nreq < $maxreq) { |
658 | return unless @$entries; |
486 | my $ent = pop @$entries; |
659 | my $entry = pop @$entries; |
|
|
660 | |
|
|
661 | aioreq_pri $pri; |
|
|
662 | add $statgrp aio_stat "$path/$entry/.", sub { |
|
|
663 | if ($_[0] < 0) { |
|
|
664 | push @nondirs, $entry; |
|
|
665 | } else { |
|
|
666 | # need to check for real directory |
|
|
667 | aioreq_pri $pri; |
|
|
668 | add $statgrp aio_lstat "$path/$entry", sub { |
|
|
669 | if (-d _) { |
|
|
670 | push @dirs, $entry; |
|
|
671 | |
|
|
672 | unless (--$ndirs) { |
|
|
673 | push @nondirs, @$entries; |
|
|
674 | feed $statgrp; |
|
|
675 | } |
|
|
676 | } else { |
|
|
677 | push @nondirs, $entry; |
|
|
678 | } |
487 | $nreq++; |
679 | } |
488 | add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
|
|
489 | } |
680 | } |
490 | } elsif (!$nreq) { |
|
|
491 | # finished |
|
|
492 | $statgrp->cancel; |
|
|
493 | undef $statcb; |
|
|
494 | undef $schedcb; |
|
|
495 | $grp->result (\@dirs, \@nondirs); |
|
|
496 | } |
681 | }; |
497 | }; |
682 | }; |
498 | $statcb = sub { |
|
|
499 | my ($status, $entry) = @_; |
|
|
500 | |
|
|
501 | if ($status < 0) { |
|
|
502 | $nreq--; |
|
|
503 | push @nondirs, $entry; |
|
|
504 | &$schedcb; |
|
|
505 | } else { |
|
|
506 | # need to check for real directory |
|
|
507 | add $grp aio_lstat "$path/$entry", sub { |
|
|
508 | $nreq--; |
|
|
509 | |
|
|
510 | if (-d _) { |
|
|
511 | push @dirs, $entry; |
|
|
512 | |
|
|
513 | if (!--$ndirs) { |
|
|
514 | push @nondirs, @$entries; |
|
|
515 | $entries = []; |
|
|
516 | } |
|
|
517 | } else { |
|
|
518 | push @nondirs, $entry; |
|
|
519 | } |
|
|
520 | |
|
|
521 | &$schedcb; |
|
|
522 | } |
|
|
523 | } |
|
|
524 | }; |
|
|
525 | |
|
|
526 | &$schedcb while @$entries && $nreq < $maxreq; |
|
|
527 | }; |
683 | }; |
528 | }; |
684 | }; |
529 | }; |
685 | }; |
530 | |
686 | |
531 | $grp |
687 | $grp |
… | |
… | |
544 | If this call isn't available because your OS lacks it or it couldn't be |
700 | If this call isn't available because your OS lacks it or it couldn't be |
545 | detected, it will be emulated by calling C<fsync> instead. |
701 | detected, it will be emulated by calling C<fsync> instead. |
546 | |
702 | |
547 | =item aio_group $callback->(...) |
703 | =item aio_group $callback->(...) |
548 | |
704 | |
549 | [EXPERIMENTAL] |
|
|
550 | |
|
|
551 | This is a very special aio request: Instead of doing something, it is a |
705 | This is a very special aio request: Instead of doing something, it is a |
552 | container for other aio requests, which is useful if you want to bundle |
706 | container for other aio requests, which is useful if you want to bundle |
553 | many requests into a single, composite, request. |
707 | many requests into a single, composite, request with a definite callback |
|
|
708 | and the ability to cancel the whole request with its subrequests. |
554 | |
709 | |
555 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
710 | Returns an object of class L<IO::AIO::GRP>. See its documentation below |
556 | for more info. |
711 | for more info. |
557 | |
712 | |
558 | Example: |
713 | Example: |
… | |
… | |
577 | phase and still requires a worker thread. Thus, the callback will not |
732 | phase and still requires a worker thread. Thus, the callback will not |
578 | be executed immediately but only after other requests in the queue have |
733 | be executed immediately but only after other requests in the queue have |
579 | entered their execution phase. This can be used to measure request |
734 | entered their execution phase. This can be used to measure request |
580 | latency. |
735 | latency. |
581 | |
736 | |
582 | =item IO::AIO::aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
737 | =item IO::AIO::aio_busy $fractional_seconds, $callback->() *NOT EXPORTED* |
583 | |
738 | |
584 | Mainly used for debugging and benchmarking, this aio request puts one of |
739 | Mainly used for debugging and benchmarking, this aio request puts one of |
585 | the request workers to sleep for the given time. |
740 | the request workers to sleep for the given time. |
586 | |
741 | |
587 | While it is theoretically handy to have simple I/O scheduling requests |
742 | While it is theoretically handy to have simple I/O scheduling requests |
588 | like sleep and file handle readable/writable, the overhead this creates |
743 | like sleep and file handle readable/writable, the overhead this creates is |
589 | is immense, so do not use this function except to put your application |
744 | immense (it blocks a thread for a long time) so do not use this function |
590 | under artificial I/O pressure. |
745 | except to put your application under artificial I/O pressure. |
591 | |
746 | |
592 | =back |
747 | =back |
593 | |
748 | |
594 | =head2 IO::AIO::REQ CLASS |
749 | =head2 IO::AIO::REQ CLASS |
595 | |
750 | |
596 | All non-aggregate C<aio_*> functions return an object of this class when |
751 | All non-aggregate C<aio_*> functions return an object of this class when |
597 | called in non-void context. |
752 | called in non-void context. |
598 | |
|
|
599 | A request always moves through the following five states in its lifetime, |
|
|
600 | in order: B<ready> (request has been created, but has not been executed |
|
|
601 | yet), B<execute> (request is currently being executed), B<pending> |
|
|
602 | (request has been executed but callback has not been called yet), |
|
|
603 | B<result> (results are being processed synchronously, includes calling the |
|
|
604 | callback) and B<done> (request has reached the end of its lifetime and |
|
|
605 | holds no resources anymore). |
|
|
606 | |
753 | |
607 | =over 4 |
754 | =over 4 |
608 | |
755 | |
609 | =item cancel $req |
756 | =item cancel $req |
610 | |
757 | |
… | |
… | |
664 | =item * They can also can also be added to other IO::AIO::GRP objects. |
811 | =item * They can also can also be added to other IO::AIO::GRP objects. |
665 | |
812 | |
666 | =item * You must not add requests to a group from within the group callback (or |
813 | =item * You must not add requests to a group from within the group callback (or |
667 | any later time). |
814 | any later time). |
668 | |
815 | |
669 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
670 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
671 | this kind of concurrency-limiting. |
|
|
672 | |
|
|
673 | =back |
816 | =back |
674 | |
817 | |
675 | Their lifetime, simplified, looks like this: when they are empty, they |
818 | Their lifetime, simplified, looks like this: when they are empty, they |
676 | will finish very quickly. If they contain only requests that are in the |
819 | will finish very quickly. If they contain only requests that are in the |
677 | C<done> state, they will also finish. Otherwise they will continue to |
820 | C<done> state, they will also finish. Otherwise they will continue to |
… | |
… | |
692 | be added, including other groups, as long as you do not create circular |
835 | be added, including other groups, as long as you do not create circular |
693 | dependencies. |
836 | dependencies. |
694 | |
837 | |
695 | Returns all its arguments. |
838 | Returns all its arguments. |
696 | |
839 | |
|
|
840 | =item $grp->cancel_subs |
|
|
841 | |
|
|
842 | Cancel all subrequests and clears any feeder, but not the group request |
|
|
843 | itself. Useful when you queued a lot of events but got a result early. |
|
|
844 | |
697 | =item $grp->result (...) |
845 | =item $grp->result (...) |
698 | |
846 | |
699 | Set the result value(s) that will be passed to the group callback when all |
847 | Set the result value(s) that will be passed to the group callback when all |
700 | subrequests have finished. By default, no argument will be passed. |
848 | subrequests have finished and set thre groups errno to the current value |
|
|
849 | of errno (just like calling C<errno> without an error number). By default, |
|
|
850 | no argument will be passed and errno is zero. |
|
|
851 | |
|
|
852 | =item $grp->errno ([$errno]) |
|
|
853 | |
|
|
854 | Sets the group errno value to C<$errno>, or the current value of errno |
|
|
855 | when the argument is missing. |
|
|
856 | |
|
|
857 | Every aio request has an associated errno value that is restored when |
|
|
858 | the callback is invoked. This method lets you change this value from its |
|
|
859 | default (0). |
|
|
860 | |
|
|
861 | Calling C<result> will also set errno, so make sure you either set C<$!> |
|
|
862 | before the call to C<result>, or call c<errno> after it. |
701 | |
863 | |
702 | =item feed $grp $callback->($grp) |
864 | =item feed $grp $callback->($grp) |
703 | |
|
|
704 | [VERY EXPERIMENTAL] |
|
|
705 | |
865 | |
706 | Sets a feeder/generator on this group: every group can have an attached |
866 | Sets a feeder/generator on this group: every group can have an attached |
707 | generator that generates requests if idle. The idea behind this is that, |
867 | generator that generates requests if idle. The idea behind this is that, |
708 | although you could just queue as many requests as you want in a group, |
868 | although you could just queue as many requests as you want in a group, |
709 | this might starve other requests for a potentially long time. For |
869 | this might starve other requests for a potentially long time. For |
… | |
… | |
746 | |
906 | |
747 | =back |
907 | =back |
748 | |
908 | |
749 | =head2 SUPPORT FUNCTIONS |
909 | =head2 SUPPORT FUNCTIONS |
750 | |
910 | |
|
|
911 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
912 | |
751 | =over 4 |
913 | =over 4 |
752 | |
914 | |
753 | =item $fileno = IO::AIO::poll_fileno |
915 | =item $fileno = IO::AIO::poll_fileno |
754 | |
916 | |
755 | Return the I<request result pipe file descriptor>. This filehandle must be |
917 | Return the I<request result pipe file descriptor>. This filehandle must be |
… | |
… | |
759 | |
921 | |
760 | See C<poll_cb> for an example. |
922 | See C<poll_cb> for an example. |
761 | |
923 | |
762 | =item IO::AIO::poll_cb |
924 | =item IO::AIO::poll_cb |
763 | |
925 | |
764 | Process all outstanding events on the result pipe. You have to call this |
926 | Process some outstanding events on the result pipe. You have to call this |
765 | regularly. Returns the number of events processed. Returns immediately |
927 | regularly. Returns the number of events processed. Returns immediately |
766 | when no events are outstanding. |
928 | when no events are outstanding. The amount of events processed depends on |
|
|
929 | the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. |
|
|
930 | |
|
|
931 | If not all requests were processed for whatever reason, the filehandle |
|
|
932 | will still be ready when C<poll_cb> returns. |
767 | |
933 | |
768 | Example: Install an Event watcher that automatically calls |
934 | Example: Install an Event watcher that automatically calls |
769 | IO::AIO::poll_cb with high priority: |
935 | IO::AIO::poll_cb with high priority: |
770 | |
936 | |
771 | Event->io (fd => IO::AIO::poll_fileno, |
937 | Event->io (fd => IO::AIO::poll_fileno, |
772 | poll => 'r', async => 1, |
938 | poll => 'r', async => 1, |
773 | cb => \&IO::AIO::poll_cb); |
939 | cb => \&IO::AIO::poll_cb); |
774 | |
940 | |
|
|
941 | =item IO::AIO::max_poll_reqs $nreqs |
|
|
942 | |
|
|
943 | =item IO::AIO::max_poll_time $seconds |
|
|
944 | |
|
|
945 | These set the maximum number of requests (default C<0>, meaning infinity) |
|
|
946 | that are being processed by C<IO::AIO::poll_cb> in one call, respectively |
|
|
947 | the maximum amount of time (default C<0>, meaning infinity) spent in |
|
|
948 | C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount |
|
|
949 | of time C<poll_cb> is allowed to use). |
|
|
950 | |
|
|
951 | Setting C<max_poll_time> to a non-zero value creates an overhead of one |
|
|
952 | syscall per request processed, which is not normally a problem unless your |
|
|
953 | callbacks are really really fast or your OS is really really slow (I am |
|
|
954 | not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead. |
|
|
955 | |
|
|
956 | Setting these is useful if you want to ensure some level of |
|
|
957 | interactiveness when perl is not fast enough to process all requests in |
|
|
958 | time. |
|
|
959 | |
|
|
960 | For interactive programs, values such as C<0.01> to C<0.1> should be fine. |
|
|
961 | |
|
|
962 | Example: Install an Event watcher that automatically calls |
|
|
963 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
|
|
964 | program get the CPU sometimes even under high AIO load. |
|
|
965 | |
|
|
966 | # try not to spend much more than 0.1s in poll_cb |
|
|
967 | IO::AIO::max_poll_time 0.1; |
|
|
968 | |
|
|
969 | # use a low priority so other tasks have priority |
|
|
970 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
971 | poll => 'r', nice => 1, |
|
|
972 | cb => &IO::AIO::poll_cb); |
|
|
973 | |
775 | =item IO::AIO::poll_wait |
974 | =item IO::AIO::poll_wait |
776 | |
975 | |
777 | Wait till the result filehandle becomes ready for reading (simply does a |
976 | Wait till the result filehandle becomes ready for reading (simply does a |
778 | C<select> on the filehandle. This is useful if you want to synchronously wait |
977 | C<select> on the filehandle. This is useful if you want to synchronously |
779 | for some requests to finish). |
978 | wait for some requests to finish). |
780 | |
979 | |
781 | See C<nreqs> for an example. |
980 | See C<nreqs> for an example. |
782 | |
981 | |
|
|
982 | =item IO::AIO::poll |
|
|
983 | |
|
|
984 | Waits until some requests have been handled. |
|
|
985 | |
|
|
986 | Strictly equivalent to: |
|
|
987 | |
|
|
988 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
989 | if IO::AIO::nreqs; |
|
|
990 | |
783 | =item IO::AIO::nreqs |
991 | =item IO::AIO::flush |
784 | |
992 | |
785 | Returns the number of requests currently outstanding (i.e. for which their |
993 | Wait till all outstanding AIO requests have been handled. |
786 | callback has not been invoked yet). |
|
|
787 | |
994 | |
788 | Example: wait till there are no outstanding requests anymore: |
995 | Strictly equivalent to: |
789 | |
996 | |
790 | IO::AIO::poll_wait, IO::AIO::poll_cb |
997 | IO::AIO::poll_wait, IO::AIO::poll_cb |
791 | while IO::AIO::nreqs; |
998 | while IO::AIO::nreqs; |
792 | |
999 | |
793 | =item IO::AIO::flush |
1000 | =head3 CONTROLLING THE NUMBER OF THREADS |
794 | |
|
|
795 | Wait till all outstanding AIO requests have been handled. |
|
|
796 | |
|
|
797 | Strictly equivalent to: |
|
|
798 | |
|
|
799 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
800 | while IO::AIO::nreqs; |
|
|
801 | |
|
|
802 | =item IO::AIO::poll |
|
|
803 | |
|
|
804 | Waits until some requests have been handled. |
|
|
805 | |
|
|
806 | Strictly equivalent to: |
|
|
807 | |
|
|
808 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
809 | if IO::AIO::nreqs; |
|
|
810 | |
1001 | |
811 | =item IO::AIO::min_parallel $nthreads |
1002 | =item IO::AIO::min_parallel $nthreads |
812 | |
1003 | |
813 | Set the minimum number of AIO threads to C<$nthreads>. The current |
1004 | Set the minimum number of AIO threads to C<$nthreads>. The current |
814 | default is C<8>, which means eight asynchronous operations can execute |
1005 | default is C<8>, which means eight asynchronous operations can execute |
815 | concurrently at any one time (the number of outstanding requests, |
1006 | concurrently at any one time (the number of outstanding requests, |
816 | however, is unlimited). |
1007 | however, is unlimited). |
817 | |
1008 | |
818 | IO::AIO starts threads only on demand, when an AIO request is queued and |
1009 | IO::AIO starts threads only on demand, when an AIO request is queued and |
819 | no free thread exists. |
1010 | no free thread exists. Please note that queueing up a hundred requests can |
|
|
1011 | create demand for a hundred threads, even if it turns out that everything |
|
|
1012 | is in the cache and could have been processed faster by a single thread. |
820 | |
1013 | |
821 | It is recommended to keep the number of threads relatively low, as some |
1014 | It is recommended to keep the number of threads relatively low, as some |
822 | Linux kernel versions will scale negatively with the number of threads |
1015 | Linux kernel versions will scale negatively with the number of threads |
823 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
1016 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
824 | versions, 4-32 threads should be fine. |
1017 | versions, 4-32 threads should be fine. |
… | |
… | |
838 | This module automatically runs C<max_parallel 0> at program end, to ensure |
1031 | This module automatically runs C<max_parallel 0> at program end, to ensure |
839 | that all threads are killed and that there are no outstanding requests. |
1032 | that all threads are killed and that there are no outstanding requests. |
840 | |
1033 | |
841 | Under normal circumstances you don't need to call this function. |
1034 | Under normal circumstances you don't need to call this function. |
842 | |
1035 | |
|
|
1036 | =item IO::AIO::max_idle $nthreads |
|
|
1037 | |
|
|
1038 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
|
|
1039 | threads that did not get a request to process within 10 seconds). That |
|
|
1040 | means if a thread becomes idle while C<$nthreads> other threads are also |
|
|
1041 | idle, it will free its resources and exit. |
|
|
1042 | |
|
|
1043 | This is useful when you allow a large number of threads (e.g. 100 or 1000) |
|
|
1044 | to allow for extremely high load situations, but want to free resources |
|
|
1045 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
|
|
1046 | |
|
|
1047 | The default is probably ok in most situations, especially if thread |
|
|
1048 | creation is fast. If thread creation is very slow on your system you might |
|
|
1049 | want to use larger values. |
|
|
1050 | |
843 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
1051 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
844 | |
1052 | |
845 | [DEPRECATED] |
1053 | This is a very bad function to use in interactive programs because it |
|
|
1054 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
|
|
1055 | use an C<aio_group> together with a feed callback. |
846 | |
1056 | |
847 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
1057 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
848 | try to queue up more than this number of requests, the caller will block until |
1058 | to queue up more than this number of requests, the next call to the |
849 | some requests have been handled. |
1059 | C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) |
|
|
1060 | function will block until the limit is no longer exceeded. |
850 | |
1061 | |
851 | The default is very large, so normally there is no practical limit. If you |
1062 | The default value is very large, so there is no practical limit on the |
852 | queue up many requests in a loop it often improves speed if you set |
1063 | number of outstanding requests. |
853 | this to a relatively low number, such as C<100>. |
|
|
854 | |
1064 | |
855 | This function does not work well together with C<aio_group>'s, and their |
1065 | You can still queue as many requests as you want. Therefore, |
856 | feeder interface is better suited to limiting concurrency, so do not use |
1066 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
857 | this function. |
1067 | as a stop gap to shield against fatal memory overflow (with large values). |
858 | |
1068 | |
859 | Under normal circumstances you don't need to call this function. |
1069 | =head3 STATISTICAL INFORMATION |
|
|
1070 | |
|
|
1071 | =item IO::AIO::nreqs |
|
|
1072 | |
|
|
1073 | Returns the number of requests currently in the ready, execute or pending |
|
|
1074 | states (i.e. for which their callback has not been invoked yet). |
|
|
1075 | |
|
|
1076 | Example: wait till there are no outstanding requests anymore: |
|
|
1077 | |
|
|
1078 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1079 | while IO::AIO::nreqs; |
|
|
1080 | |
|
|
1081 | =item IO::AIO::nready |
|
|
1082 | |
|
|
1083 | Returns the number of requests currently in the ready state (not yet |
|
|
1084 | executed). |
|
|
1085 | |
|
|
1086 | =item IO::AIO::npending |
|
|
1087 | |
|
|
1088 | Returns the number of requests currently in the pending state (executed, |
|
|
1089 | but not yet processed by poll_cb). |
860 | |
1090 | |
861 | =back |
1091 | =back |
862 | |
1092 | |
863 | =cut |
1093 | =cut |
864 | |
1094 | |
… | |
… | |
879 | } |
1109 | } |
880 | |
1110 | |
881 | min_parallel 8; |
1111 | min_parallel 8; |
882 | |
1112 | |
883 | END { |
1113 | END { |
884 | max_parallel 0; |
1114 | min_parallel 1; |
885 | } |
1115 | flush; |
|
|
1116 | }; |
886 | |
1117 | |
887 | 1; |
1118 | 1; |
888 | |
1119 | |
889 | =head2 FORK BEHAVIOUR |
1120 | =head2 FORK BEHAVIOUR |
890 | |
1121 | |
891 | This module should do "the right thing" when the process using it forks: |
1122 | This module should do "the right thing" when the process using it forks: |
892 | |
1123 | |
893 | Before the fork, IO::AIO enters a quiescent state where no requests |
1124 | Before the fork, IO::AIO enters a quiescent state where no requests |
894 | can be added in other threads and no results will be processed. After |
1125 | can be added in other threads and no results will be processed. After |
895 | the fork the parent simply leaves the quiescent state and continues |
1126 | the fork the parent simply leaves the quiescent state and continues |
896 | request/result processing, while the child clears the request/result |
1127 | request/result processing, while the child frees the request/result queue |
897 | queue (so the requests started before the fork will only be handled in |
1128 | (so that the requests started before the fork will only be handled in the |
898 | the parent). Threads will be started on demand until the limit ste in the |
1129 | parent). Threads will be started on demand until the limit set in the |
899 | parent process has been reached again. |
1130 | parent process has been reached again. |
900 | |
1131 | |
901 | In short: the parent will, after a short pause, continue as if fork had |
1132 | In short: the parent will, after a short pause, continue as if fork had |
902 | not been called, while the child will act as if IO::AIO has not been used |
1133 | not been called, while the child will act as if IO::AIO has not been used |
903 | yet. |
1134 | yet. |
904 | |
1135 | |
905 | =head2 MEMORY USAGE |
1136 | =head2 MEMORY USAGE |
906 | |
1137 | |
|
|
1138 | Per-request usage: |
|
|
1139 | |
907 | Each aio request uses - depending on your architecture - around 128 bytes |
1140 | Each aio request uses - depending on your architecture - around 100-200 |
908 | of memory. In addition, stat requests need a stat buffer (possibly a few |
1141 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
909 | hundred bytes). Perl scalars and other data passed into aio requests will |
1142 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
910 | also be locked. |
1143 | scalars and other data passed into aio requests will also be locked and |
|
|
1144 | will consume memory till the request has entered the done state. |
911 | |
1145 | |
912 | This is now awfully much, so queuing lots of requests is not usually a |
1146 | This is now awfully much, so queuing lots of requests is not usually a |
913 | problem. |
1147 | problem. |
914 | |
1148 | |
915 | Each thread needs a stack area which is usually around 16k, sometimes much |
1149 | Per-thread usage: |
916 | larger, depending on the OS. |
1150 | |
|
|
1151 | In the execution phase, some aio requests require more memory for |
|
|
1152 | temporary buffers, and each thread requires a stack and other data |
|
|
1153 | structures (usually around 16k-128k, depending on the OS). |
|
|
1154 | |
|
|
1155 | =head1 KNOWN BUGS |
|
|
1156 | |
|
|
1157 | Known bugs will be fixed in the next release. |
917 | |
1158 | |
918 | =head1 SEE ALSO |
1159 | =head1 SEE ALSO |
919 | |
1160 | |
920 | L<Coro::AIO>. |
1161 | L<Coro::AIO>. |
921 | |
1162 | |