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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 = '3.3'; |
55 | our $VERSION = '3.7'; |
56 | |
56 | |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
58 | our %EXPORT_TAGS = ( |
58 | our %EXPORT_TAGS = ( |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
60 | ); |
60 | ); |
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108 | |
108 | |
109 | The current coroutine (the last coroutine switched to). The initial value |
109 | The current coroutine (the last coroutine switched to). The initial value |
110 | is C<$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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159 | # cannot destroy itself. |
161 | # cannot destroy itself. |
160 | my @destroy; |
162 | my @destroy; |
161 | my $manager; |
163 | my $manager; |
162 | |
164 | |
163 | $manager = new Coro sub { |
165 | $manager = new Coro sub { |
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166 | $current->desc ("[coro manager]"); |
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167 | |
164 | while () { |
168 | while () { |
165 | (shift @destroy)->_cancel |
169 | (shift @destroy)->_cancel |
166 | while @destroy; |
170 | while @destroy; |
167 | |
171 | |
168 | &schedule; |
172 | &schedule; |
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185 | |
189 | |
186 | Create a new asynchronous coroutine and return it's coroutine object |
190 | Create a new asynchronous coroutine and return it's coroutine object |
187 | (usually unused). When the sub returns the new coroutine is automatically |
191 | (usually unused). When the sub returns the new coroutine is automatically |
188 | terminated. |
192 | terminated. |
189 | |
193 | |
190 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
194 | Calling C<exit> in a coroutine will do the same as calling exit outside |
191 | |
195 | 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 |
196 | just as it would in the main program. |
193 | program. |
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194 | |
197 | |
195 | # create a new coroutine that just prints its arguments |
198 | # create a new coroutine that just prints its arguments |
196 | async { |
199 | async { |
197 | print "@_\n"; |
200 | print "@_\n"; |
198 | } 1,2,3,4; |
201 | } 1,2,3,4; |
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229 | terminate }> once per second or so to slowly replenish the pool. |
232 | terminate }> once per second or so to slowly replenish the pool. |
230 | |
233 | |
231 | =cut |
234 | =cut |
232 | |
235 | |
233 | our $POOL_SIZE = 8; |
236 | our $POOL_SIZE = 8; |
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237 | our $MAX_POOL_RSS = 64 * 1024; |
234 | our @pool; |
238 | our @pool; |
235 | |
239 | |
236 | sub pool_handler { |
240 | sub pool_handler { |
237 | while () { |
241 | while () { |
238 | my ($cb, @arg) = @{ delete $current->{_invoke} }; |
242 | $current->{desc} = "[async_pool]"; |
239 | |
243 | |
240 | eval { |
244 | eval { |
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245 | my ($cb, @arg) = @{ delete $current->{_invoke} or return }; |
241 | $cb->(@arg); |
246 | $cb->(@arg); |
242 | }; |
247 | }; |
243 | warn $@ if $@; |
248 | warn $@ if $@; |
244 | |
249 | |
245 | last if @pool >= $POOL_SIZE; |
250 | last if @pool >= $POOL_SIZE || $current->rss >= $MAX_POOL_RSS; |
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251 | |
246 | push @pool, $current; |
252 | push @pool, $current; |
247 | |
253 | $current->{desc} = "[async_pool idle]"; |
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254 | $current->save (Coro::State::SAVE_DEF); |
248 | $current->prio (0); |
255 | $current->prio (0); |
249 | schedule; |
256 | schedule; |
250 | } |
257 | } |
251 | } |
258 | } |
252 | |
259 | |
253 | sub async_pool(&@) { |
260 | sub async_pool(&@) { |
254 | # this is also inlined into the unlock_scheduler |
261 | # this is also inlined into the unlock_scheduler |
255 | my $coro = (pop @pool or new Coro \&pool_handler); |
262 | my $coro = (pop @pool) || new Coro \&pool_handler;; |
256 | |
263 | |
257 | $coro->{_invoke} = [@_]; |
264 | $coro->{_invoke} = [@_]; |
258 | $coro->ready; |
265 | $coro->ready; |
259 | |
266 | |
260 | $coro |
267 | $coro |
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278 | # wake up sleeping coroutine |
285 | # wake up sleeping coroutine |
279 | $current->ready; |
286 | $current->ready; |
280 | undef $current; |
287 | undef $current; |
281 | }; |
288 | }; |
282 | |
289 | |
283 | # call schedule until event occured. |
290 | # call schedule until event occurred. |
284 | # in case we are woken up for other reasons |
291 | # in case we are woken up for other reasons |
285 | # (current still defined), loop. |
292 | # (current still defined), loop. |
286 | Coro::schedule while $current; |
293 | Coro::schedule while $current; |
287 | } |
294 | } |
288 | |
295 | |
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326 | Create a new coroutine and return it. When the sub returns the coroutine |
333 | Create a new coroutine and return it. When the sub returns the coroutine |
327 | automatically terminates as if C<terminate> with the returned values were |
334 | automatically terminates as if C<terminate> with the returned values were |
328 | called. To make the coroutine run you must first put it into the ready queue |
335 | called. To make the coroutine run you must first put it into the ready queue |
329 | by calling the ready method. |
336 | by calling the ready method. |
330 | |
337 | |
331 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
338 | See C<async> for additional discussion. |
332 | |
339 | |
333 | =cut |
340 | =cut |
334 | |
341 | |
335 | sub _run_coro { |
342 | sub _run_coro { |
336 | terminate &{+shift}; |
343 | terminate &{+shift}; |
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459 | =over 4 |
466 | =over 4 |
460 | |
467 | |
461 | =item Coro::nready |
468 | =item Coro::nready |
462 | |
469 | |
463 | Returns the number of coroutines that are currently in the ready state, |
470 | Returns the number of coroutines that are currently in the ready state, |
464 | i.e. that can be swicthed to. The value C<0> means that the only runnable |
471 | i.e. that can be switched to. The value C<0> means that the only runnable |
465 | coroutine is the currently running one, so C<cede> would have no effect, |
472 | coroutine is the currently running one, so C<cede> would have no effect, |
466 | and C<schedule> would cause a deadlock unless there is an idle handler |
473 | and C<schedule> would cause a deadlock unless there is an idle handler |
467 | that wakes up some coroutines. |
474 | that wakes up some coroutines. |
468 | |
475 | |
469 | =item my $guard = Coro::guard { ... } |
476 | =item my $guard = Coro::guard { ... } |
470 | |
477 | |
471 | This creates and returns a guard object. Nothing happens until the objetc |
478 | This creates and returns a guard object. Nothing happens until the object |
472 | gets destroyed, in which case the codeblock given as argument will be |
479 | gets destroyed, in which case the codeblock given as argument will be |
473 | executed. This is useful to free locks or other resources in case of a |
480 | executed. This is useful to free locks or other resources in case of a |
474 | runtime error or when the coroutine gets canceled, as in both cases the |
481 | runtime error or when the coroutine gets canceled, as in both cases the |
475 | guard block will be executed. The guard object supports only one method, |
482 | guard block will be executed. The guard object supports only one method, |
476 | C<< ->cancel >>, which will keep the codeblock from being executed. |
483 | C<< ->cancel >>, which will keep the codeblock from being executed. |
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505 | This utility function takes a BLOCK or code reference and "unblocks" it, |
512 | This utility function takes a BLOCK or code reference and "unblocks" it, |
506 | returning the new coderef. This means that the new coderef will return |
513 | returning the new coderef. This means that the new coderef will return |
507 | immediately without blocking, returning nothing, while the original code |
514 | immediately without blocking, returning nothing, while the original code |
508 | ref will be called (with parameters) from within its own coroutine. |
515 | ref will be called (with parameters) from within its own coroutine. |
509 | |
516 | |
510 | The reason this fucntion exists is that many event libraries (such as the |
517 | The reason this function exists is that many event libraries (such as the |
511 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
518 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
512 | of thread-safety). This means you must not block within event callbacks, |
519 | of thread-safety). This means you must not block within event callbacks, |
513 | otherwise you might suffer from crashes or worse. |
520 | otherwise you might suffer from crashes or worse. |
514 | |
521 | |
515 | This function allows your callbacks to block by executing them in another |
522 | This function allows your callbacks to block by executing them in another |
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527 | # we create a special coro because we want to cede, |
534 | # we create a special coro because we want to cede, |
528 | # to reduce pressure on the coro pool (because most callbacks |
535 | # to reduce pressure on the coro pool (because most callbacks |
529 | # return immediately and can be reused) and because we cannot cede |
536 | # return immediately and can be reused) and because we cannot cede |
530 | # inside an event callback. |
537 | # inside an event callback. |
531 | our $unblock_scheduler = async { |
538 | our $unblock_scheduler = async { |
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539 | $current->desc ("[unblock_sub scheduler]"); |
532 | while () { |
540 | while () { |
533 | while (my $cb = pop @unblock_queue) { |
541 | while (my $cb = pop @unblock_queue) { |
534 | # this is an inlined copy of async_pool |
542 | # this is an inlined copy of async_pool |
535 | my $coro = (pop @pool or new Coro \&pool_handler); |
543 | my $coro = (pop @pool or new Coro \&pool_handler); |
536 | |
544 | |
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561 | |
569 | |
562 | - you must make very sure that no coro is still active on global |
570 | - you must make very sure that no coro is still active on global |
563 | destruction. very bad things might happen otherwise (usually segfaults). |
571 | destruction. very bad things might happen otherwise (usually segfaults). |
564 | |
572 | |
565 | - this module is not thread-safe. You should only ever use this module |
573 | - this module is not thread-safe. You should only ever use this module |
566 | from the same thread (this requirement might be losened in the future |
574 | from the same thread (this requirement might be loosened in the future |
567 | to allow per-thread schedulers, but Coro::State does not yet allow |
575 | to allow per-thread schedulers, but Coro::State does not yet allow |
568 | this). |
576 | this). |
569 | |
577 | |
570 | =head1 SEE ALSO |
578 | =head1 SEE ALSO |
571 | |
579 | |