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20 | |
20 | |
21 | =head1 DESCRIPTION |
21 | =head1 DESCRIPTION |
22 | |
22 | |
23 | This module collection manages coroutines. Coroutines are similar |
23 | This module collection manages coroutines. Coroutines are similar |
24 | to threads but don't run in parallel at the same time even on SMP |
24 | to threads but don't run in parallel at the same time even on SMP |
25 | machines. The specific flavor of coroutine use din this module also |
25 | machines. The specific flavor of coroutine used in this module also |
26 | guarentees you that it will not switch between coroutines unless |
26 | guarantees you that it will not switch between coroutines unless |
27 | necessary, at easily-identified points in your program, so locking and |
27 | necessary, at easily-identified points in your program, so locking and |
28 | parallel access are rarely an issue, making coroutine programming much |
28 | parallel access are rarely an issue, making coroutine programming much |
29 | safer than threads programming. |
29 | safer than threads programming. |
30 | |
30 | |
31 | (Perl, however, does not natively support real threads but instead does a |
31 | (Perl, however, does not natively support real threads but instead does a |
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50 | |
50 | |
51 | our $idle; # idle handler |
51 | our $idle; # idle handler |
52 | our $main; # main coroutine |
52 | our $main; # main coroutine |
53 | our $current; # current coroutine |
53 | our $current; # current coroutine |
54 | |
54 | |
55 | our $VERSION = '3.51'; |
55 | our $VERSION = '3.8'; |
56 | |
56 | |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
58 | our %EXPORT_TAGS = ( |
58 | our %EXPORT_TAGS = ( |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
60 | ); |
60 | ); |
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108 | |
108 | |
109 | The current coroutine (the last coroutine switched to). The initial value |
109 | The current coroutine (the last coroutine switched to). The initial value |
110 | is C<$main> (of course). |
110 | is C<$main> (of course). |
111 | |
111 | |
112 | This variable is B<strictly> I<read-only>. It is provided for performance |
112 | This variable is B<strictly> I<read-only>. It is provided for performance |
113 | reasons. If performance is not essentiel you are encouraged to use the |
113 | reasons. If performance is not essential you are encouraged to use the |
114 | C<Coro::current> function instead. |
114 | C<Coro::current> function instead. |
115 | |
115 | |
116 | =cut |
116 | =cut |
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117 | |
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118 | $main->{desc} = "[main::]"; |
117 | |
119 | |
118 | # maybe some other module used Coro::Specific before... |
120 | # maybe some other module used Coro::Specific before... |
119 | $main->{specific} = $current->{specific} |
121 | $main->{specific} = $current->{specific} |
120 | if $current; |
122 | if $current; |
121 | |
123 | |
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166 | while @destroy; |
168 | while @destroy; |
167 | |
169 | |
168 | &schedule; |
170 | &schedule; |
169 | } |
171 | } |
170 | }; |
172 | }; |
171 | |
173 | $manager->desc ("[coro manager]"); |
172 | $manager->prio (PRIO_MAX); |
174 | $manager->prio (PRIO_MAX); |
173 | |
175 | |
174 | # static methods. not really. |
176 | # static methods. not really. |
175 | |
177 | |
176 | =back |
178 | =back |
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185 | |
187 | |
186 | Create a new asynchronous coroutine and return it's coroutine object |
188 | Create a new asynchronous coroutine and return it's coroutine object |
187 | (usually unused). When the sub returns the new coroutine is automatically |
189 | (usually unused). When the sub returns the new coroutine is automatically |
188 | terminated. |
190 | terminated. |
189 | |
191 | |
190 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
192 | Calling C<exit> in a coroutine will do the same as calling exit outside |
191 | |
193 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
192 | When the coroutine dies, the program will exit, just as in the main |
194 | just as it would in the main program. |
193 | program. |
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194 | |
195 | |
195 | # create a new coroutine that just prints its arguments |
196 | # create a new coroutine that just prints its arguments |
196 | async { |
197 | async { |
197 | print "@_\n"; |
198 | print "@_\n"; |
198 | } 1,2,3,4; |
199 | } 1,2,3,4; |
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223 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
224 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
224 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
225 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
225 | required. |
226 | required. |
226 | |
227 | |
227 | If you are concerned about pooled coroutines growing a lot because a |
228 | If you are concerned about pooled coroutines growing a lot because a |
228 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool { |
229 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
229 | terminate }> once per second or so to slowly replenish the pool. |
230 | { terminate }> once per second or so to slowly replenish the pool. In |
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231 | addition to that, when the stacks used by a handler grows larger than 16kb |
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232 | (adjustable with $Coro::POOL_RSS) it will also exit. |
230 | |
233 | |
231 | =cut |
234 | =cut |
232 | |
235 | |
233 | our $POOL_SIZE = 8; |
236 | our $POOL_SIZE = 8; |
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237 | our $POOL_RSS = 16 * 1024; |
234 | our @pool; |
238 | our @async_pool; |
235 | |
239 | |
236 | sub pool_handler { |
240 | sub pool_handler { |
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241 | my $cb; |
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242 | |
237 | while () { |
243 | while () { |
238 | eval { |
244 | eval { |
239 | my ($cb, @arg) = @{ delete $current->{_invoke} or return }; |
245 | while () { |
240 | $cb->(@arg); |
246 | _pool_1 $cb; |
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247 | &$cb; |
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248 | _pool_2 $cb; |
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249 | &schedule; |
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250 | } |
241 | }; |
251 | }; |
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252 | |
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253 | last if $@ eq "\3terminate\2\n"; |
242 | warn $@ if $@; |
254 | warn $@ if $@; |
243 | |
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244 | last if @pool >= $POOL_SIZE; |
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245 | push @pool, $current; |
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246 | |
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247 | $current->prio (0); |
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248 | schedule; |
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249 | } |
255 | } |
250 | } |
256 | } |
251 | |
257 | |
252 | sub async_pool(&@) { |
258 | sub async_pool(&@) { |
253 | # this is also inlined into the unlock_scheduler |
259 | # this is also inlined into the unlock_scheduler |
254 | my $coro = (pop @pool or new Coro \&pool_handler); |
260 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
255 | |
261 | |
256 | $coro->{_invoke} = [@_]; |
262 | $coro->{_invoke} = [@_]; |
257 | $coro->ready; |
263 | $coro->ready; |
258 | |
264 | |
259 | $coro |
265 | $coro |
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277 | # wake up sleeping coroutine |
283 | # wake up sleeping coroutine |
278 | $current->ready; |
284 | $current->ready; |
279 | undef $current; |
285 | undef $current; |
280 | }; |
286 | }; |
281 | |
287 | |
282 | # call schedule until event occured. |
288 | # call schedule until event occurred. |
283 | # in case we are woken up for other reasons |
289 | # in case we are woken up for other reasons |
284 | # (current still defined), loop. |
290 | # (current still defined), loop. |
285 | Coro::schedule while $current; |
291 | Coro::schedule while $current; |
286 | } |
292 | } |
287 | |
293 | |
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302 | |
308 | |
303 | =item terminate [arg...] |
309 | =item terminate [arg...] |
304 | |
310 | |
305 | Terminates the current coroutine with the given status values (see L<cancel>). |
311 | Terminates the current coroutine with the given status values (see L<cancel>). |
306 | |
312 | |
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313 | =item killall |
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314 | |
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315 | Kills/terminates/cancels all coroutines except the currently running |
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316 | one. This is useful after a fork, either in the child or the parent, as |
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317 | usually only one of them should inherit the running coroutines. |
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318 | |
307 | =cut |
319 | =cut |
308 | |
320 | |
309 | sub terminate { |
321 | sub terminate { |
310 | $current->cancel (@_); |
322 | $current->cancel (@_); |
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323 | } |
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324 | |
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325 | sub killall { |
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326 | for (Coro::State::list) { |
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327 | $_->cancel |
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328 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
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329 | } |
311 | } |
330 | } |
312 | |
331 | |
313 | =back |
332 | =back |
314 | |
333 | |
315 | # dynamic methods |
334 | # dynamic methods |
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325 | Create a new coroutine and return it. When the sub returns the coroutine |
344 | Create a new coroutine and return it. When the sub returns the coroutine |
326 | automatically terminates as if C<terminate> with the returned values were |
345 | automatically terminates as if C<terminate> with the returned values were |
327 | called. To make the coroutine run you must first put it into the ready queue |
346 | called. To make the coroutine run you must first put it into the ready queue |
328 | by calling the ready method. |
347 | by calling the ready method. |
329 | |
348 | |
330 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
349 | See C<async> for additional discussion. |
331 | |
350 | |
332 | =cut |
351 | =cut |
333 | |
352 | |
334 | sub _run_coro { |
353 | sub _run_coro { |
335 | terminate &{+shift}; |
354 | terminate &{+shift}; |
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458 | =over 4 |
477 | =over 4 |
459 | |
478 | |
460 | =item Coro::nready |
479 | =item Coro::nready |
461 | |
480 | |
462 | Returns the number of coroutines that are currently in the ready state, |
481 | Returns the number of coroutines that are currently in the ready state, |
463 | i.e. that can be swicthed to. The value C<0> means that the only runnable |
482 | i.e. that can be switched to. The value C<0> means that the only runnable |
464 | coroutine is the currently running one, so C<cede> would have no effect, |
483 | coroutine is the currently running one, so C<cede> would have no effect, |
465 | and C<schedule> would cause a deadlock unless there is an idle handler |
484 | and C<schedule> would cause a deadlock unless there is an idle handler |
466 | that wakes up some coroutines. |
485 | that wakes up some coroutines. |
467 | |
486 | |
468 | =item my $guard = Coro::guard { ... } |
487 | =item my $guard = Coro::guard { ... } |
469 | |
488 | |
470 | This creates and returns a guard object. Nothing happens until the objetc |
489 | This creates and returns a guard object. Nothing happens until the object |
471 | gets destroyed, in which case the codeblock given as argument will be |
490 | gets destroyed, in which case the codeblock given as argument will be |
472 | executed. This is useful to free locks or other resources in case of a |
491 | executed. This is useful to free locks or other resources in case of a |
473 | runtime error or when the coroutine gets canceled, as in both cases the |
492 | runtime error or when the coroutine gets canceled, as in both cases the |
474 | guard block will be executed. The guard object supports only one method, |
493 | guard block will be executed. The guard object supports only one method, |
475 | C<< ->cancel >>, which will keep the codeblock from being executed. |
494 | C<< ->cancel >>, which will keep the codeblock from being executed. |
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504 | This utility function takes a BLOCK or code reference and "unblocks" it, |
523 | This utility function takes a BLOCK or code reference and "unblocks" it, |
505 | returning the new coderef. This means that the new coderef will return |
524 | returning the new coderef. This means that the new coderef will return |
506 | immediately without blocking, returning nothing, while the original code |
525 | immediately without blocking, returning nothing, while the original code |
507 | ref will be called (with parameters) from within its own coroutine. |
526 | ref will be called (with parameters) from within its own coroutine. |
508 | |
527 | |
509 | The reason this fucntion exists is that many event libraries (such as the |
528 | The reason this function exists is that many event libraries (such as the |
510 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
529 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
511 | of thread-safety). This means you must not block within event callbacks, |
530 | of thread-safety). This means you must not block within event callbacks, |
512 | otherwise you might suffer from crashes or worse. |
531 | otherwise you might suffer from crashes or worse. |
513 | |
532 | |
514 | This function allows your callbacks to block by executing them in another |
533 | This function allows your callbacks to block by executing them in another |
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525 | |
544 | |
526 | # we create a special coro because we want to cede, |
545 | # we create a special coro because we want to cede, |
527 | # to reduce pressure on the coro pool (because most callbacks |
546 | # to reduce pressure on the coro pool (because most callbacks |
528 | # return immediately and can be reused) and because we cannot cede |
547 | # return immediately and can be reused) and because we cannot cede |
529 | # inside an event callback. |
548 | # inside an event callback. |
530 | our $unblock_scheduler = async { |
549 | our $unblock_scheduler = new Coro sub { |
531 | while () { |
550 | while () { |
532 | while (my $cb = pop @unblock_queue) { |
551 | while (my $cb = pop @unblock_queue) { |
533 | # this is an inlined copy of async_pool |
552 | # this is an inlined copy of async_pool |
534 | my $coro = (pop @pool or new Coro \&pool_handler); |
553 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
535 | |
554 | |
536 | $coro->{_invoke} = $cb; |
555 | $coro->{_invoke} = $cb; |
537 | $coro->ready; |
556 | $coro->ready; |
538 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
557 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
539 | } |
558 | } |
540 | schedule; # sleep well |
559 | schedule; # sleep well |
541 | } |
560 | } |
542 | }; |
561 | }; |
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562 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
543 | |
563 | |
544 | sub unblock_sub(&) { |
564 | sub unblock_sub(&) { |
545 | my $cb = shift; |
565 | my $cb = shift; |
546 | |
566 | |
547 | sub { |
567 | sub { |
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560 | |
580 | |
561 | - you must make very sure that no coro is still active on global |
581 | - you must make very sure that no coro is still active on global |
562 | destruction. very bad things might happen otherwise (usually segfaults). |
582 | destruction. very bad things might happen otherwise (usually segfaults). |
563 | |
583 | |
564 | - this module is not thread-safe. You should only ever use this module |
584 | - this module is not thread-safe. You should only ever use this module |
565 | from the same thread (this requirement might be losened in the future |
585 | from the same thread (this requirement might be loosened in the future |
566 | to allow per-thread schedulers, but Coro::State does not yet allow |
586 | to allow per-thread schedulers, but Coro::State does not yet allow |
567 | this). |
587 | this). |
568 | |
588 | |
569 | =head1 SEE ALSO |
589 | =head1 SEE ALSO |
570 | |
590 | |