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Revision 1.108 by root, Fri Jan 5 20:00:49 2007 UTC vs.
Revision 1.141 by root, Tue Oct 2 10:38:17 2007 UTC

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20 20
21=head1 DESCRIPTION 21=head1 DESCRIPTION
22 22
23This module collection manages coroutines. Coroutines are similar 23This module collection manages coroutines. Coroutines are similar
24to threads but don't run in parallel at the same time even on SMP 24to threads but don't run in parallel at the same time even on SMP
25machines. The specific flavor of coroutine use din this module also 25machines. The specific flavor of coroutine used in this module also
26guarentees you that it will not switch between coroutines unless 26guarantees you that it will not switch between coroutines unless
27necessary, at easily-identified points in your program, so locking and 27necessary, at easily-identified points in your program, so locking and
28parallel access are rarely an issue, making coroutine programming much 28parallel access are rarely an issue, making coroutine programming much
29safer than threads programming. 29safer 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
51our $idle; # idle handler 51our $idle; # idle handler
52our $main; # main coroutine 52our $main; # main coroutine
53our $current; # current coroutine 53our $current; # current coroutine
54 54
55our $VERSION = '3.3'; 55our $VERSION = '3.8';
56 56
57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
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108 108
109The current coroutine (the last coroutine switched to). The initial value 109The current coroutine (the last coroutine switched to). The initial value
110is C<$main> (of course). 110is C<$main> (of course).
111 111
112This variable is B<strictly> I<read-only>. It is provided for performance 112This variable is B<strictly> I<read-only>. It is provided for performance
113reasons. If performance is not essentiel you are encouraged to use the 113reasons. If performance is not essential you are encouraged to use the
114C<Coro::current> function instead. 114C<Coro::current> function instead.
115 115
116=cut 116=cut
117
118$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
186Create a new asynchronous coroutine and return it's coroutine object 188Create 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
188terminated. 190terminated.
189 191
190Calling C<exit> in a coroutine will not work correctly, so do not do that. 192Calling C<exit> in a coroutine will do the same as calling exit outside
191 193the coroutine. Likewise, when the coroutine dies, the program will exit,
192When the coroutine dies, the program will exit, just as in the main 194just as it would in the main program.
193program.
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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223The pool size is limited to 8 idle coroutines (this can be adjusted by 224The pool size is limited to 8 idle coroutines (this can be adjusted by
224changing $Coro::POOL_SIZE), and there can be as many non-idle coros as 225changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
225required. 226required.
226 227
227If you are concerned about pooled coroutines growing a lot because a 228If you are concerned about pooled coroutines growing a lot because a
228single C<async_pool> used a lot of stackspace you can e.g. C<async_pool { 229single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
229terminate }> once per second or so to slowly replenish the pool. 230{ terminate }> once per second or so to slowly replenish the pool. In
231addition to that, when the stacks used by a handler grows larger than 16kb
232(adjustable with $Coro::POOL_RSS) it will also exit.
230 233
231=cut 234=cut
232 235
233our $POOL_SIZE = 8; 236our $POOL_SIZE = 8;
237our $POOL_RSS = 16 * 1024;
234our @pool; 238our @async_pool;
235 239
236sub pool_handler { 240sub pool_handler {
241 my $cb;
242
237 while () { 243 while () {
238 my ($cb, @arg) = @{ delete $current->{_invoke} };
239
240 eval { 244 eval {
241 $cb->(@arg); 245 while () {
246 _pool_1 $cb;
247 &$cb;
248 _pool_2 $cb;
249 &schedule;
250 }
242 }; 251 };
252
253 last if $@ eq "\3terminate\2\n";
243 warn $@ if $@; 254 warn $@ if $@;
244
245 last if @pool >= $POOL_SIZE;
246 push @pool, $current;
247
248 $current->prio (0);
249 schedule;
250 } 255 }
251} 256}
252 257
253sub async_pool(&@) { 258sub async_pool(&@) {
254 # this is also inlined into the unlock_scheduler 259 # this is also inlined into the unlock_scheduler
255 my $coro = (pop @pool or new Coro \&pool_handler); 260 my $coro = (pop @async_pool) || new Coro \&pool_handler;
256 261
257 $coro->{_invoke} = [@_]; 262 $coro->{_invoke} = [@_];
258 $coro->ready; 263 $coro->ready;
259 264
260 $coro 265 $coro
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278 # wake up sleeping coroutine 283 # wake up sleeping coroutine
279 $current->ready; 284 $current->ready;
280 undef $current; 285 undef $current;
281 }; 286 };
282 287
283 # call schedule until event occured. 288 # call schedule until event occurred.
284 # in case we are woken up for other reasons 289 # in case we are woken up for other reasons
285 # (current still defined), loop. 290 # (current still defined), loop.
286 Coro::schedule while $current; 291 Coro::schedule while $current;
287 } 292 }
288 293
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303 308
304=item terminate [arg...] 309=item terminate [arg...]
305 310
306Terminates the current coroutine with the given status values (see L<cancel>). 311Terminates the current coroutine with the given status values (see L<cancel>).
307 312
313=item killall
314
315Kills/terminates/cancels all coroutines except the currently running
316one. This is useful after a fork, either in the child or the parent, as
317usually only one of them should inherit the running coroutines.
318
308=cut 319=cut
309 320
310sub terminate { 321sub terminate {
311 $current->cancel (@_); 322 $current->cancel (@_);
323}
324
325sub killall {
326 for (Coro::State::list) {
327 $_->cancel
328 if $_ != $current && UNIVERSAL::isa $_, "Coro";
329 }
312} 330}
313 331
314=back 332=back
315 333
316# dynamic methods 334# dynamic methods
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326Create a new coroutine and return it. When the sub returns the coroutine 344Create a new coroutine and return it. When the sub returns the coroutine
327automatically terminates as if C<terminate> with the returned values were 345automatically terminates as if C<terminate> with the returned values were
328called. To make the coroutine run you must first put it into the ready queue 346called. To make the coroutine run you must first put it into the ready queue
329by calling the ready method. 347by calling the ready method.
330 348
331Calling C<exit> in a coroutine will not work correctly, so do not do that. 349See C<async> for additional discussion.
332 350
333=cut 351=cut
334 352
335sub _run_coro { 353sub _run_coro {
336 terminate &{+shift}; 354 terminate &{+shift};
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459=over 4 477=over 4
460 478
461=item Coro::nready 479=item Coro::nready
462 480
463Returns the number of coroutines that are currently in the ready state, 481Returns the number of coroutines that are currently in the ready state,
464i.e. that can be swicthed to. The value C<0> means that the only runnable 482i.e. that can be switched to. The value C<0> means that the only runnable
465coroutine is the currently running one, so C<cede> would have no effect, 483coroutine is the currently running one, so C<cede> would have no effect,
466and C<schedule> would cause a deadlock unless there is an idle handler 484and C<schedule> would cause a deadlock unless there is an idle handler
467that wakes up some coroutines. 485that wakes up some coroutines.
468 486
469=item my $guard = Coro::guard { ... } 487=item my $guard = Coro::guard { ... }
470 488
471This creates and returns a guard object. Nothing happens until the objetc 489This creates and returns a guard object. Nothing happens until the object
472gets destroyed, in which case the codeblock given as argument will be 490gets destroyed, in which case the codeblock given as argument will be
473executed. This is useful to free locks or other resources in case of a 491executed. This is useful to free locks or other resources in case of a
474runtime error or when the coroutine gets canceled, as in both cases the 492runtime error or when the coroutine gets canceled, as in both cases the
475guard block will be executed. The guard object supports only one method, 493guard block will be executed. The guard object supports only one method,
476C<< ->cancel >>, which will keep the codeblock from being executed. 494C<< ->cancel >>, which will keep the codeblock from being executed.
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505This utility function takes a BLOCK or code reference and "unblocks" it, 523This utility function takes a BLOCK or code reference and "unblocks" it,
506returning the new coderef. This means that the new coderef will return 524returning the new coderef. This means that the new coderef will return
507immediately without blocking, returning nothing, while the original code 525immediately without blocking, returning nothing, while the original code
508ref will be called (with parameters) from within its own coroutine. 526ref will be called (with parameters) from within its own coroutine.
509 527
510The reason this fucntion exists is that many event libraries (such as the 528The reason this function exists is that many event libraries (such as the
511venerable L<Event|Event> module) are not coroutine-safe (a weaker form 529venerable L<Event|Event> module) are not coroutine-safe (a weaker form
512of thread-safety). This means you must not block within event callbacks, 530of thread-safety). This means you must not block within event callbacks,
513otherwise you might suffer from crashes or worse. 531otherwise you might suffer from crashes or worse.
514 532
515This function allows your callbacks to block by executing them in another 533This function allows your callbacks to block by executing them in another
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526 544
527# we create a special coro because we want to cede, 545# we create a special coro because we want to cede,
528# to reduce pressure on the coro pool (because most callbacks 546# to reduce pressure on the coro pool (because most callbacks
529# return immediately and can be reused) and because we cannot cede 547# return immediately and can be reused) and because we cannot cede
530# inside an event callback. 548# inside an event callback.
531our $unblock_scheduler = async { 549our $unblock_scheduler = new Coro sub {
532 while () { 550 while () {
533 while (my $cb = pop @unblock_queue) { 551 while (my $cb = pop @unblock_queue) {
534 # this is an inlined copy of async_pool 552 # this is an inlined copy of async_pool
535 my $coro = (pop @pool or new Coro \&pool_handler); 553 my $coro = (pop @async_pool) || new Coro \&pool_handler;
536 554
537 $coro->{_invoke} = $cb; 555 $coro->{_invoke} = $cb;
538 $coro->ready; 556 $coro->ready;
539 cede; # for short-lived callbacks, this reduces pressure on the coro pool 557 cede; # for short-lived callbacks, this reduces pressure on the coro pool
540 } 558 }
541 schedule; # sleep well 559 schedule; # sleep well
542 } 560 }
543}; 561};
562$unblock_scheduler->desc ("[unblock_sub scheduler]");
544 563
545sub unblock_sub(&) { 564sub unblock_sub(&) {
546 my $cb = shift; 565 my $cb = shift;
547 566
548 sub { 567 sub {
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561 580
562 - 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
563 destruction. very bad things might happen otherwise (usually segfaults). 582 destruction. very bad things might happen otherwise (usually segfaults).
564 583
565 - 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
566 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
567 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
568 this). 587 this).
569 588
570=head1 SEE ALSO 589=head1 SEE ALSO
571 590

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