… | |
… | |
61 | etc.), but can also be used to easily do operations in parallel that are |
61 | etc.), but can also be used to easily do operations in parallel that are |
62 | normally done sequentially, e.g. stat'ing many files, which is much faster |
62 | normally done sequentially, e.g. stat'ing many files, which is much faster |
63 | on a RAID volume or over NFS when you do a number of stat operations |
63 | on a RAID volume or over NFS when you do a number of stat operations |
64 | concurrently. |
64 | concurrently. |
65 | |
65 | |
66 | While this works on all types of file descriptors (for example sockets), |
66 | While most of this works on all types of file descriptors (for example |
67 | using these functions on file descriptors that support nonblocking |
67 | sockets), using these functions on file descriptors that support |
68 | operation (again, sockets, pipes etc.) is very inefficient. Use an event |
68 | nonblocking operation (again, sockets, pipes etc.) is very inefficient or |
|
|
69 | might not work (aio_read fails on sockets/pipes/fifos). Use an event loop |
69 | loop for that (such as the L<Event|Event> module): IO::AIO will naturally |
70 | for that (such as the L<Event|Event> module): IO::AIO will naturally fit |
70 | fit into such an event loop itself. |
71 | into such an event loop itself. |
71 | |
72 | |
72 | In this version, a number of threads are started that execute your |
73 | In this version, a number of threads are started that execute your |
73 | requests and signal their completion. You don't need thread support |
74 | requests and signal their completion. You don't need thread support |
74 | in perl, and the threads created by this module will not be visible |
75 | in perl, and the threads created by this module will not be visible |
75 | to perl. In the future, this module might make use of the native aio |
76 | to perl. In the future, this module might make use of the native aio |
… | |
… | |
82 | Although the module will work with in the presence of other (Perl-) |
83 | Although the module will work with in the presence of other (Perl-) |
83 | threads, it is currently not reentrant in any way, so use appropriate |
84 | threads, it is currently not reentrant in any way, so use appropriate |
84 | locking yourself, always call C<poll_cb> from within the same thread, or |
85 | locking yourself, always call C<poll_cb> from within the same thread, or |
85 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
86 | never call C<poll_cb> (or other C<aio_> functions) recursively. |
86 | |
87 | |
|
|
88 | =head2 EXAMPLE |
|
|
89 | |
|
|
90 | This is a simple example that uses the Event module and loads |
|
|
91 | F</etc/passwd> asynchronously: |
|
|
92 | |
|
|
93 | use Fcntl; |
|
|
94 | use Event; |
|
|
95 | use IO::AIO; |
|
|
96 | |
|
|
97 | # register the IO::AIO callback with Event |
|
|
98 | Event->io (fd => IO::AIO::poll_fileno, |
|
|
99 | poll => 'r', |
|
|
100 | cb => \&IO::AIO::poll_cb); |
|
|
101 | |
|
|
102 | # queue the request to open /etc/passwd |
|
|
103 | aio_open "/etc/passwd", O_RDONLY, 0, sub { |
|
|
104 | my $fh = $_[0] |
|
|
105 | or die "error while opening: $!"; |
|
|
106 | |
|
|
107 | # stat'ing filehandles is generally non-blocking |
|
|
108 | my $size = -s $fh; |
|
|
109 | |
|
|
110 | # queue a request to read the file |
|
|
111 | my $contents; |
|
|
112 | aio_read $fh, 0, $size, $contents, 0, sub { |
|
|
113 | $_[0] == $size |
|
|
114 | or die "short read: $!"; |
|
|
115 | |
|
|
116 | close $fh; |
|
|
117 | |
|
|
118 | # file contents now in $contents |
|
|
119 | print $contents; |
|
|
120 | |
|
|
121 | # exit event loop and program |
|
|
122 | Event::unloop; |
|
|
123 | }; |
|
|
124 | }; |
|
|
125 | |
|
|
126 | # possibly queue up other requests, or open GUI windows, |
|
|
127 | # check for sockets etc. etc. |
|
|
128 | |
|
|
129 | # process events as long as there are some: |
|
|
130 | Event::loop; |
|
|
131 | |
87 | =head1 REQUEST ANATOMY AND LIFETIME |
132 | =head1 REQUEST ANATOMY AND LIFETIME |
88 | |
133 | |
89 | Every C<aio_*> function creates a request. which is a C data structure not |
134 | Every C<aio_*> function creates a request. which is a C data structure not |
90 | directly visible to Perl. |
135 | directly visible to Perl. |
91 | |
136 | |
… | |
… | |
132 | Request has reached the end of its lifetime and holds no resources anymore |
177 | Request has reached the end of its lifetime and holds no resources anymore |
133 | (except possibly for the Perl object, but its connection to the actual |
178 | (except possibly for the Perl object, but its connection to the actual |
134 | aio request is severed and calling its methods will either do nothing or |
179 | aio request is severed and calling its methods will either do nothing or |
135 | result in a runtime error). |
180 | result in a runtime error). |
136 | |
181 | |
|
|
182 | =back |
|
|
183 | |
137 | =cut |
184 | =cut |
138 | |
185 | |
139 | package IO::AIO; |
186 | package IO::AIO; |
140 | |
187 | |
141 | no warnings; |
188 | no warnings; |
142 | use strict 'vars'; |
189 | use strict 'vars'; |
143 | |
190 | |
144 | use base 'Exporter'; |
191 | use base 'Exporter'; |
145 | |
192 | |
146 | BEGIN { |
193 | BEGIN { |
147 | our $VERSION = '2.0'; |
194 | our $VERSION = '2.2'; |
148 | |
195 | |
149 | 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 |
150 | 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 |
151 | 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 |
152 | aio_copy aio_group aio_nop aio_mknod); |
199 | aio_move aio_copy aio_group aio_nop aio_mknod); |
153 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
200 | our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); |
154 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
201 | our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush |
155 | min_parallel max_parallel nreqs nready npending); |
202 | min_parallel max_parallel max_idle |
|
|
203 | nreqs nready npending nthreads |
|
|
204 | max_poll_time max_poll_reqs); |
156 | |
205 | |
157 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
206 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
158 | |
207 | |
159 | require XSLoader; |
208 | require XSLoader; |
160 | XSLoader::load ("IO::AIO", $VERSION); |
209 | XSLoader::load ("IO::AIO", $VERSION); |
161 | } |
210 | } |
162 | |
211 | |
163 | =head1 FUNCTIONS |
212 | =head1 FUNCTIONS |
164 | |
213 | |
165 | =head2 AIO FUNCTIONS |
214 | =head2 AIO REQUEST FUNCTIONS |
166 | |
215 | |
167 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
216 | All the C<aio_*> calls are more or less thin wrappers around the syscall |
168 | with the same name (sans C<aio_>). The arguments are similar or identical, |
217 | with the same name (sans C<aio_>). The arguments are similar or identical, |
169 | and they all accept an additional (and optional) C<$callback> argument |
218 | and they all accept an additional (and optional) C<$callback> argument |
170 | 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 |
… | |
… | |
173 | syscall has been executed asynchronously. |
222 | syscall has been executed asynchronously. |
174 | |
223 | |
175 | All functions expecting a filehandle keep a copy of the filehandle |
224 | All functions expecting a filehandle keep a copy of the filehandle |
176 | internally until the request has finished. |
225 | internally until the request has finished. |
177 | |
226 | |
178 | 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 |
179 | manipulation of those requests while they are in-flight. |
228 | further manipulation of those requests while they are in-flight. |
180 | |
229 | |
181 | 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 |
182 | 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 |
183 | request is being executed, the current working directory could have |
232 | request is being executed, the current working directory could have |
184 | changed. Alternatively, you can make sure that you never change the |
233 | changed. Alternatively, you can make sure that you never change the |
185 | current working directory. |
234 | current working directory anywhere in the program and then use relative |
|
|
235 | paths. |
186 | |
236 | |
187 | 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 |
188 | always pass in filenames you got from outside (command line, readdir |
238 | in filenames you got from outside (command line, readdir etc.) without |
189 | 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 |
190 | 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 |
191 | 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) |
192 | use something else. |
242 | use something else to ensure your scalar has the correct contents. |
|
|
243 | |
|
|
244 | This works, btw. independent of the internal UTF-8 bit, which IO::AIO |
|
|
245 | handles correctly wether it is set or not. |
193 | |
246 | |
194 | =over 4 |
247 | =over 4 |
195 | |
248 | |
196 | =item $prev_pri = aioreq_pri [$pri] |
249 | =item $prev_pri = aioreq_pri [$pri] |
197 | |
250 | |
… | |
… | |
220 | }; |
273 | }; |
221 | |
274 | |
222 | =item aioreq_nice $pri_adjust |
275 | =item aioreq_nice $pri_adjust |
223 | |
276 | |
224 | 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 |
225 | priority, so effects are cumulative. |
278 | priority, so the effect is cumulative. |
226 | |
279 | |
227 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
280 | =item aio_open $pathname, $flags, $mode, $callback->($fh) |
228 | |
281 | |
229 | 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 |
230 | created filehandle for the file. |
283 | created filehandle for the file. |
… | |
… | |
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 | |
350 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
403 | =item aio_mknod $path, $mode, $dev, $callback->($status) |
351 | |
404 | |
|
|
405 | [EXPERIMENTAL] |
|
|
406 | |
352 | Asynchronously create a device node (or fifo). See mknod(2). |
407 | Asynchronously create a device node (or fifo). See mknod(2). |
353 | |
408 | |
354 | The only portable (POSIX) way of calling this function is: |
409 | The only (POSIX-) portable way of calling this function is: |
355 | |
410 | |
356 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
411 | aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... |
357 | |
412 | |
358 | =item aio_link $srcpath, $dstpath, $callback->($status) |
413 | =item aio_link $srcpath, $dstpath, $callback->($status) |
359 | |
414 | |
… | |
… | |
362 | |
417 | |
363 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
418 | =item aio_symlink $srcpath, $dstpath, $callback->($status) |
364 | |
419 | |
365 | 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 |
366 | 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. |
|
|
422 | |
|
|
423 | =item aio_readlink $path, $callback->($link) |
|
|
424 | |
|
|
425 | Asynchronously read the symlink specified by C<$path> and pass it to |
|
|
426 | the callback. If an error occurs, nothing or undef gets passed to the |
|
|
427 | callback. |
367 | |
428 | |
368 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
429 | =item aio_rename $srcpath, $dstpath, $callback->($status) |
369 | |
430 | |
370 | 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 |
371 | rename(2) and call the callback with the result code. |
432 | rename(2) and call the callback with the result code. |
… | |
… | |
845 | |
906 | |
846 | =back |
907 | =back |
847 | |
908 | |
848 | =head2 SUPPORT FUNCTIONS |
909 | =head2 SUPPORT FUNCTIONS |
849 | |
910 | |
|
|
911 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
|
|
912 | |
850 | =over 4 |
913 | =over 4 |
851 | |
914 | |
852 | =item $fileno = IO::AIO::poll_fileno |
915 | =item $fileno = IO::AIO::poll_fileno |
853 | |
916 | |
854 | 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 |
… | |
… | |
858 | |
921 | |
859 | See C<poll_cb> for an example. |
922 | See C<poll_cb> for an example. |
860 | |
923 | |
861 | =item IO::AIO::poll_cb |
924 | =item IO::AIO::poll_cb |
862 | |
925 | |
863 | 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 |
864 | regularly. Returns the number of events processed. Returns immediately |
927 | regularly. Returns the number of events processed. Returns immediately |
865 | 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>. |
866 | |
930 | |
867 | If not all requests were processed for whatever reason, the filehandle |
931 | If not all requests were processed for whatever reason, the filehandle |
868 | will still be ready when C<poll_cb> returns. |
932 | will still be ready when C<poll_cb> returns. |
869 | |
933 | |
870 | Example: Install an Event watcher that automatically calls |
934 | Example: Install an Event watcher that automatically calls |
… | |
… | |
872 | |
936 | |
873 | Event->io (fd => IO::AIO::poll_fileno, |
937 | Event->io (fd => IO::AIO::poll_fileno, |
874 | poll => 'r', async => 1, |
938 | poll => 'r', async => 1, |
875 | cb => \&IO::AIO::poll_cb); |
939 | cb => \&IO::AIO::poll_cb); |
876 | |
940 | |
877 | =item IO::AIO::poll_some $max_requests |
941 | =item IO::AIO::max_poll_reqs $nreqs |
878 | |
942 | |
879 | Similar to C<poll_cb>, but only processes up to C<$max_requests> requests |
943 | =item IO::AIO::max_poll_time $seconds |
880 | at a time. |
|
|
881 | |
944 | |
882 | Useful if you want to ensure some level of interactiveness when perl is |
945 | These set the maximum number of requests (default C<0>, meaning infinity) |
883 | not fast enough to process all requests in time. |
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. |
884 | |
961 | |
885 | Example: Install an Event watcher that automatically calls |
962 | Example: Install an Event watcher that automatically calls |
886 | IO::AIO::poll_some with low priority, to ensure that other parts of the |
963 | IO::AIO::poll_cb with low priority, to ensure that other parts of the |
887 | program get the CPU sometimes even under high AIO load. |
964 | program get the CPU sometimes even under high AIO load. |
888 | |
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 |
889 | Event->io (fd => IO::AIO::poll_fileno, |
970 | Event->io (fd => IO::AIO::poll_fileno, |
890 | poll => 'r', nice => 1, |
971 | poll => 'r', nice => 1, |
891 | cb => sub { IO::AIO::poll_some 256 }); |
972 | cb => &IO::AIO::poll_cb); |
892 | |
973 | |
893 | =item IO::AIO::poll_wait |
974 | =item IO::AIO::poll_wait |
894 | |
975 | |
895 | 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 |
896 | 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 |
897 | for some requests to finish). |
978 | wait for some requests to finish). |
898 | |
979 | |
899 | See C<nreqs> for an example. |
980 | See C<nreqs> for an example. |
900 | |
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 | |
901 | =item IO::AIO::nreqs |
991 | =item IO::AIO::flush |
902 | |
992 | |
903 | Returns the number of requests currently in the ready, execute or pending |
993 | Wait till all outstanding AIO requests have been handled. |
904 | states (i.e. for which their callback has not been invoked yet). |
|
|
905 | |
994 | |
906 | Example: wait till there are no outstanding requests anymore: |
995 | Strictly equivalent to: |
907 | |
996 | |
908 | IO::AIO::poll_wait, IO::AIO::poll_cb |
997 | IO::AIO::poll_wait, IO::AIO::poll_cb |
909 | while IO::AIO::nreqs; |
998 | while IO::AIO::nreqs; |
910 | |
999 | |
911 | =item IO::AIO::nready |
1000 | =head3 CONTROLLING THE NUMBER OF THREADS |
912 | |
|
|
913 | Returns the number of requests currently in the ready state (not yet |
|
|
914 | executed). |
|
|
915 | |
|
|
916 | =item IO::AIO::npending |
|
|
917 | |
|
|
918 | Returns the number of requests currently in the pending state (executed, |
|
|
919 | but not yet processed by poll_cb). |
|
|
920 | |
|
|
921 | =item IO::AIO::flush |
|
|
922 | |
|
|
923 | Wait till all outstanding AIO requests have been handled. |
|
|
924 | |
|
|
925 | Strictly equivalent to: |
|
|
926 | |
|
|
927 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
928 | while IO::AIO::nreqs; |
|
|
929 | |
|
|
930 | =item IO::AIO::poll |
|
|
931 | |
|
|
932 | Waits until some requests have been handled. |
|
|
933 | |
|
|
934 | Strictly equivalent to: |
|
|
935 | |
|
|
936 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
937 | if IO::AIO::nreqs; |
|
|
938 | |
1001 | |
939 | =item IO::AIO::min_parallel $nthreads |
1002 | =item IO::AIO::min_parallel $nthreads |
940 | |
1003 | |
941 | Set the minimum number of AIO threads to C<$nthreads>. The current |
1004 | Set the minimum number of AIO threads to C<$nthreads>. The current |
942 | default is C<8>, which means eight asynchronous operations can execute |
1005 | default is C<8>, which means eight asynchronous operations can execute |
943 | concurrently at any one time (the number of outstanding requests, |
1006 | concurrently at any one time (the number of outstanding requests, |
944 | however, is unlimited). |
1007 | however, is unlimited). |
945 | |
1008 | |
946 | 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 |
947 | 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. |
948 | |
1013 | |
949 | 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 |
950 | Linux kernel versions will scale negatively with the number of threads |
1015 | Linux kernel versions will scale negatively with the number of threads |
951 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
1016 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
952 | versions, 4-32 threads should be fine. |
1017 | versions, 4-32 threads should be fine. |
… | |
… | |
966 | 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 |
967 | 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. |
968 | |
1033 | |
969 | Under normal circumstances you don't need to call this function. |
1034 | Under normal circumstances you don't need to call this function. |
970 | |
1035 | |
|
|
1036 | =item IO::AIO::max_idle $nthreads |
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1037 | |
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|
1038 | Limit the number of threads (default: 4) that are allowed to idle (i.e., |
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|
1039 | threads that did not get a request to process within 10 seconds). That |
|
|
1040 | means if a thread becomes idle while C<$nthreads> other threads are also |
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|
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 |
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|
1045 | under normal circumstances (1000 threads can easily consume 30MB of RAM). |
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1046 | |
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|
1047 | The default is probably ok in most situations, especially if thread |
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|
1048 | creation is fast. If thread creation is very slow on your system you might |
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|
1049 | want to use larger values. |
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1050 | |
971 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
1051 | =item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs |
972 | |
1052 | |
973 | This is a very bad function to use in interactive programs because it |
1053 | This is a very bad function to use in interactive programs because it |
974 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
1054 | blocks, and a bad way to reduce concurrency because it is inexact: Better |
975 | use an C<aio_group> together with a feed callback. |
1055 | use an C<aio_group> together with a feed callback. |
… | |
… | |
983 | number of outstanding requests. |
1063 | number of outstanding requests. |
984 | |
1064 | |
985 | You can still queue as many requests as you want. Therefore, |
1065 | You can still queue as many requests as you want. Therefore, |
986 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
1066 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
987 | as a stop gap to shield against fatal memory overflow (with large values). |
1067 | as a stop gap to shield against fatal memory overflow (with large values). |
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1068 | |
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1069 | =head3 STATISTICAL INFORMATION |
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1070 | |
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|
1071 | =item IO::AIO::nreqs |
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|
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). |
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|
1075 | |
|
|
1076 | Example: wait till there are no outstanding requests anymore: |
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1077 | |
|
|
1078 | IO::AIO::poll_wait, IO::AIO::poll_cb |
|
|
1079 | while IO::AIO::nreqs; |
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|
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). |
988 | |
1090 | |
989 | =back |
1091 | =back |
990 | |
1092 | |
991 | =cut |
1093 | =cut |
992 | |
1094 | |