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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 = '3.55'; |
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 $self->{destroy_cb}) || []}; |
156 | } |
158 | } |
157 | |
159 | |
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160 | sub _do_trace_sub { |
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161 | &{$current->{_trace_sub_cb}} |
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162 | } |
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163 | |
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164 | sub _do_trace_line { |
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165 | &{$current->{_trace_line_cb}} |
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166 | } |
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167 | |
158 | # this coroutine is necessary because a coroutine |
168 | # this coroutine is necessary because a coroutine |
159 | # cannot destroy itself. |
169 | # cannot destroy itself. |
160 | my @destroy; |
170 | my @destroy; |
161 | my $manager; |
171 | my $manager; |
162 | |
172 | |
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166 | while @destroy; |
176 | while @destroy; |
167 | |
177 | |
168 | &schedule; |
178 | &schedule; |
169 | } |
179 | } |
170 | }; |
180 | }; |
171 | |
181 | $manager->desc ("[coro manager]"); |
172 | $manager->prio (PRIO_MAX); |
182 | $manager->prio (PRIO_MAX); |
173 | |
183 | |
174 | # static methods. not really. |
184 | # static methods. not really. |
175 | |
185 | |
176 | =back |
186 | =back |
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185 | |
195 | |
186 | Create a new asynchronous coroutine and return it's coroutine object |
196 | Create a new asynchronous coroutine and return it's coroutine object |
187 | (usually unused). When the sub returns the new coroutine is automatically |
197 | (usually unused). When the sub returns the new coroutine is automatically |
188 | terminated. |
198 | terminated. |
189 | |
199 | |
190 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
200 | Calling C<exit> in a coroutine will do the same as calling exit outside |
191 | |
201 | 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 |
202 | just as it would in the main program. |
193 | program. |
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194 | |
203 | |
195 | # create a new coroutine that just prints its arguments |
204 | # create a new coroutine that just prints its arguments |
196 | async { |
205 | async { |
197 | print "@_\n"; |
206 | print "@_\n"; |
198 | } 1,2,3,4; |
207 | } 1,2,3,4; |
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223 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
232 | 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 |
233 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
225 | required. |
234 | required. |
226 | |
235 | |
227 | If you are concerned about pooled coroutines growing a lot because a |
236 | 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 { |
237 | 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. |
238 | { terminate }> once per second or so to slowly replenish the pool. In |
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239 | addition to that, when the stacks used by a handler grows larger than 16kb |
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240 | (adjustable with $Coro::POOL_RSS) it will also exit. |
230 | |
241 | |
231 | =cut |
242 | =cut |
232 | |
243 | |
233 | our $POOL_SIZE = 8; |
244 | our $POOL_SIZE = 8; |
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245 | our $POOL_RSS = 16 * 1024; |
234 | our @pool; |
246 | our @async_pool; |
235 | |
247 | |
236 | sub pool_handler { |
248 | sub pool_handler { |
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249 | my $cb; |
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250 | |
237 | while () { |
251 | while () { |
238 | eval { |
252 | eval { |
239 | my ($cb, @arg) = @{ delete $current->{_invoke} or return }; |
253 | while () { |
240 | $cb->(@arg); |
254 | _pool_1 $cb; |
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255 | &$cb; |
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256 | _pool_2 $cb; |
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257 | &schedule; |
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258 | } |
241 | }; |
259 | }; |
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260 | |
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261 | last if $@ eq "\3terminate\2\n"; |
242 | warn $@ if $@; |
262 | 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->save (Coro::State::SAVE_DEF); |
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248 | $current->prio (0); |
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249 | schedule; |
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250 | } |
263 | } |
251 | } |
264 | } |
252 | |
265 | |
253 | sub async_pool(&@) { |
266 | sub async_pool(&@) { |
254 | # this is also inlined into the unlock_scheduler |
267 | # this is also inlined into the unlock_scheduler |
255 | my $coro = (pop @pool or new Coro \&pool_handler); |
268 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
256 | |
269 | |
257 | $coro->{_invoke} = [@_]; |
270 | $coro->{_invoke} = [@_]; |
258 | $coro->ready; |
271 | $coro->ready; |
259 | |
272 | |
260 | $coro |
273 | $coro |
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278 | # wake up sleeping coroutine |
291 | # wake up sleeping coroutine |
279 | $current->ready; |
292 | $current->ready; |
280 | undef $current; |
293 | undef $current; |
281 | }; |
294 | }; |
282 | |
295 | |
283 | # call schedule until event occured. |
296 | # call schedule until event occurred. |
284 | # in case we are woken up for other reasons |
297 | # in case we are woken up for other reasons |
285 | # (current still defined), loop. |
298 | # (current still defined), loop. |
286 | Coro::schedule while $current; |
299 | Coro::schedule while $current; |
287 | } |
300 | } |
288 | |
301 | |
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326 | Create a new coroutine and return it. When the sub returns the coroutine |
339 | 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 |
340 | 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 |
341 | called. To make the coroutine run you must first put it into the ready queue |
329 | by calling the ready method. |
342 | by calling the ready method. |
330 | |
343 | |
331 | Calling C<exit> in a coroutine will not work correctly, so do not do that. |
344 | See C<async> for additional discussion. |
332 | |
345 | |
333 | =cut |
346 | =cut |
334 | |
347 | |
335 | sub _run_coro { |
348 | sub _run_coro { |
336 | terminate &{+shift}; |
349 | terminate &{+shift}; |
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459 | =over 4 |
472 | =over 4 |
460 | |
473 | |
461 | =item Coro::nready |
474 | =item Coro::nready |
462 | |
475 | |
463 | Returns the number of coroutines that are currently in the ready state, |
476 | 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 |
477 | 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, |
478 | 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 |
479 | and C<schedule> would cause a deadlock unless there is an idle handler |
467 | that wakes up some coroutines. |
480 | that wakes up some coroutines. |
468 | |
481 | |
469 | =item my $guard = Coro::guard { ... } |
482 | =item my $guard = Coro::guard { ... } |
470 | |
483 | |
471 | This creates and returns a guard object. Nothing happens until the objetc |
484 | 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 |
485 | 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 |
486 | 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 |
487 | 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, |
488 | guard block will be executed. The guard object supports only one method, |
476 | C<< ->cancel >>, which will keep the codeblock from being executed. |
489 | 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, |
518 | 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 |
519 | returning the new coderef. This means that the new coderef will return |
507 | immediately without blocking, returning nothing, while the original code |
520 | immediately without blocking, returning nothing, while the original code |
508 | ref will be called (with parameters) from within its own coroutine. |
521 | ref will be called (with parameters) from within its own coroutine. |
509 | |
522 | |
510 | The reason this fucntion exists is that many event libraries (such as the |
523 | 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 |
524 | 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, |
525 | of thread-safety). This means you must not block within event callbacks, |
513 | otherwise you might suffer from crashes or worse. |
526 | otherwise you might suffer from crashes or worse. |
514 | |
527 | |
515 | This function allows your callbacks to block by executing them in another |
528 | This function allows your callbacks to block by executing them in another |
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526 | |
539 | |
527 | # we create a special coro because we want to cede, |
540 | # we create a special coro because we want to cede, |
528 | # to reduce pressure on the coro pool (because most callbacks |
541 | # to reduce pressure on the coro pool (because most callbacks |
529 | # return immediately and can be reused) and because we cannot cede |
542 | # return immediately and can be reused) and because we cannot cede |
530 | # inside an event callback. |
543 | # inside an event callback. |
531 | our $unblock_scheduler = async { |
544 | our $unblock_scheduler = new Coro sub { |
532 | while () { |
545 | while () { |
533 | while (my $cb = pop @unblock_queue) { |
546 | while (my $cb = pop @unblock_queue) { |
534 | # this is an inlined copy of async_pool |
547 | # this is an inlined copy of async_pool |
535 | my $coro = (pop @pool or new Coro \&pool_handler); |
548 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
536 | |
549 | |
537 | $coro->{_invoke} = $cb; |
550 | $coro->{_invoke} = $cb; |
538 | $coro->ready; |
551 | $coro->ready; |
539 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
552 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
540 | } |
553 | } |
541 | schedule; # sleep well |
554 | schedule; # sleep well |
542 | } |
555 | } |
543 | }; |
556 | }; |
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557 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
544 | |
558 | |
545 | sub unblock_sub(&) { |
559 | sub unblock_sub(&) { |
546 | my $cb = shift; |
560 | my $cb = shift; |
547 | |
561 | |
548 | sub { |
562 | sub { |
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561 | |
575 | |
562 | - you must make very sure that no coro is still active on global |
576 | - you must make very sure that no coro is still active on global |
563 | destruction. very bad things might happen otherwise (usually segfaults). |
577 | destruction. very bad things might happen otherwise (usually segfaults). |
564 | |
578 | |
565 | - this module is not thread-safe. You should only ever use this module |
579 | - 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 |
580 | 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 |
581 | to allow per-thread schedulers, but Coro::State does not yet allow |
568 | this). |
582 | this). |
569 | |
583 | |
570 | =head1 SEE ALSO |
584 | =head1 SEE ALSO |
571 | |
585 | |