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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 = '3.501'; |
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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153 | # call all destruction callbacks |
155 | # call all destruction callbacks |
154 | $_->(@{$self->{status}}) |
156 | $_->(@{$self->{status}}) |
155 | for @{(delete $self->{destroy_cb}) || []}; |
157 | for @{(delete $self->{destroy_cb}) || []}; |
156 | } |
158 | } |
157 | |
159 | |
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160 | sub _do_trace { |
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161 | $current->{_trace_cb}->(); |
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162 | } |
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163 | |
158 | # this coroutine is necessary because a coroutine |
164 | # this coroutine is necessary because a coroutine |
159 | # cannot destroy itself. |
165 | # cannot destroy itself. |
160 | my @destroy; |
166 | my @destroy; |
161 | my $manager; |
167 | my $manager; |
162 | |
168 | |
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166 | while @destroy; |
172 | while @destroy; |
167 | |
173 | |
168 | &schedule; |
174 | &schedule; |
169 | } |
175 | } |
170 | }; |
176 | }; |
171 | |
177 | $manager->desc ("[coro manager]"); |
172 | $manager->prio (PRIO_MAX); |
178 | $manager->prio (PRIO_MAX); |
173 | |
179 | |
174 | # static methods. not really. |
180 | # static methods. not really. |
175 | |
181 | |
176 | =back |
182 | =back |
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185 | |
191 | |
186 | Create a new asynchronous coroutine and return it's coroutine object |
192 | Create a new asynchronous coroutine and return it's coroutine object |
187 | (usually unused). When the sub returns the new coroutine is automatically |
193 | (usually unused). When the sub returns the new coroutine is automatically |
188 | terminated. |
194 | terminated. |
189 | |
195 | |
190 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
196 | Calling C<exit> in a coroutine will do the same as calling exit outside |
191 | |
197 | 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 |
198 | just as it would in the main program. |
193 | program. |
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194 | |
199 | |
195 | # create a new coroutine that just prints its arguments |
200 | # create a new coroutine that just prints its arguments |
196 | async { |
201 | async { |
197 | print "@_\n"; |
202 | print "@_\n"; |
198 | } 1,2,3,4; |
203 | } 1,2,3,4; |
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223 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
228 | 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 |
229 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
225 | required. |
230 | required. |
226 | |
231 | |
227 | If you are concerned about pooled coroutines growing a lot because a |
232 | 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 { |
233 | 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. |
234 | { terminate }> once per second or so to slowly replenish the pool. In |
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235 | addition to that, when the stacks used by a handler grows larger than 16kb |
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236 | (adjustable with $Coro::POOL_RSS) it will also exit. |
230 | |
237 | |
231 | =cut |
238 | =cut |
232 | |
239 | |
233 | our $POOL_SIZE = 8; |
240 | our $POOL_SIZE = 8; |
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241 | our $POOL_RSS = 16 * 1024; |
234 | our @pool; |
242 | our @async_pool; |
235 | |
243 | |
236 | sub pool_handler { |
244 | sub pool_handler { |
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245 | my $cb; |
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246 | |
237 | while () { |
247 | while () { |
238 | eval { |
248 | eval { |
239 | my ($cb, @arg) = @{ delete $current->{_invoke} or return }; |
249 | while () { |
240 | $cb->(@arg); |
250 | _pool_1 $cb; |
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251 | &$cb; |
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252 | _pool_2 $cb; |
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253 | &schedule; |
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254 | } |
241 | }; |
255 | }; |
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256 | |
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257 | last if $@ eq "\3terminate\2\n"; |
242 | warn $@ if $@; |
258 | 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 | } |
259 | } |
250 | } |
260 | } |
251 | |
261 | |
252 | sub async_pool(&@) { |
262 | sub async_pool(&@) { |
253 | # this is also inlined into the unlock_scheduler |
263 | # this is also inlined into the unlock_scheduler |
254 | my $coro = (pop @pool or new Coro \&pool_handler); |
264 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
255 | |
265 | |
256 | $coro->{_invoke} = [@_]; |
266 | $coro->{_invoke} = [@_]; |
257 | $coro->ready; |
267 | $coro->ready; |
258 | |
268 | |
259 | $coro |
269 | $coro |
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277 | # wake up sleeping coroutine |
287 | # wake up sleeping coroutine |
278 | $current->ready; |
288 | $current->ready; |
279 | undef $current; |
289 | undef $current; |
280 | }; |
290 | }; |
281 | |
291 | |
282 | # call schedule until event occured. |
292 | # call schedule until event occurred. |
283 | # in case we are woken up for other reasons |
293 | # in case we are woken up for other reasons |
284 | # (current still defined), loop. |
294 | # (current still defined), loop. |
285 | Coro::schedule while $current; |
295 | Coro::schedule while $current; |
286 | } |
296 | } |
287 | |
297 | |
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325 | Create a new coroutine and return it. When the sub returns the coroutine |
335 | 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 |
336 | 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 |
337 | called. To make the coroutine run you must first put it into the ready queue |
328 | by calling the ready method. |
338 | by calling the ready method. |
329 | |
339 | |
330 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
340 | See C<async> for additional discussion. |
331 | |
341 | |
332 | =cut |
342 | =cut |
333 | |
343 | |
334 | sub _run_coro { |
344 | sub _run_coro { |
335 | terminate &{+shift}; |
345 | terminate &{+shift}; |
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458 | =over 4 |
468 | =over 4 |
459 | |
469 | |
460 | =item Coro::nready |
470 | =item Coro::nready |
461 | |
471 | |
462 | Returns the number of coroutines that are currently in the ready state, |
472 | 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 |
473 | 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, |
474 | 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 |
475 | and C<schedule> would cause a deadlock unless there is an idle handler |
466 | that wakes up some coroutines. |
476 | that wakes up some coroutines. |
467 | |
477 | |
468 | =item my $guard = Coro::guard { ... } |
478 | =item my $guard = Coro::guard { ... } |
469 | |
479 | |
470 | This creates and returns a guard object. Nothing happens until the objetc |
480 | 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 |
481 | 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 |
482 | 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 |
483 | 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, |
484 | guard block will be executed. The guard object supports only one method, |
475 | C<< ->cancel >>, which will keep the codeblock from being executed. |
485 | 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, |
514 | 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 |
515 | returning the new coderef. This means that the new coderef will return |
506 | immediately without blocking, returning nothing, while the original code |
516 | immediately without blocking, returning nothing, while the original code |
507 | ref will be called (with parameters) from within its own coroutine. |
517 | ref will be called (with parameters) from within its own coroutine. |
508 | |
518 | |
509 | The reason this fucntion exists is that many event libraries (such as the |
519 | 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 |
520 | 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, |
521 | of thread-safety). This means you must not block within event callbacks, |
512 | otherwise you might suffer from crashes or worse. |
522 | otherwise you might suffer from crashes or worse. |
513 | |
523 | |
514 | This function allows your callbacks to block by executing them in another |
524 | This function allows your callbacks to block by executing them in another |
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525 | |
535 | |
526 | # we create a special coro because we want to cede, |
536 | # we create a special coro because we want to cede, |
527 | # to reduce pressure on the coro pool (because most callbacks |
537 | # to reduce pressure on the coro pool (because most callbacks |
528 | # return immediately and can be reused) and because we cannot cede |
538 | # return immediately and can be reused) and because we cannot cede |
529 | # inside an event callback. |
539 | # inside an event callback. |
530 | our $unblock_scheduler = async { |
540 | our $unblock_scheduler = new Coro sub { |
531 | while () { |
541 | while () { |
532 | while (my $cb = pop @unblock_queue) { |
542 | while (my $cb = pop @unblock_queue) { |
533 | # this is an inlined copy of async_pool |
543 | # this is an inlined copy of async_pool |
534 | my $coro = (pop @pool or new Coro \&pool_handler); |
544 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
535 | |
545 | |
536 | $coro->{_invoke} = $cb; |
546 | $coro->{_invoke} = $cb; |
537 | $coro->ready; |
547 | $coro->ready; |
538 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
548 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
539 | } |
549 | } |
540 | schedule; # sleep well |
550 | schedule; # sleep well |
541 | } |
551 | } |
542 | }; |
552 | }; |
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553 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
543 | |
554 | |
544 | sub unblock_sub(&) { |
555 | sub unblock_sub(&) { |
545 | my $cb = shift; |
556 | my $cb = shift; |
546 | |
557 | |
547 | sub { |
558 | sub { |
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560 | |
571 | |
561 | - you must make very sure that no coro is still active on global |
572 | - you must make very sure that no coro is still active on global |
562 | destruction. very bad things might happen otherwise (usually segfaults). |
573 | destruction. very bad things might happen otherwise (usually segfaults). |
563 | |
574 | |
564 | - this module is not thread-safe. You should only ever use this module |
575 | - 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 |
576 | 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 |
577 | to allow per-thread schedulers, but Coro::State does not yet allow |
567 | this). |
578 | this). |
568 | |
579 | |
569 | =head1 SEE ALSO |
580 | =head1 SEE ALSO |
570 | |
581 | |