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Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC vs.
Revision 1.132 by root, Thu Sep 20 22:53:23 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 = '3.56'; 55our $VERSION = '3.7';
56 56
57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
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108 108
109The current coroutine (the last coroutine switched to). The initial value 109The current coroutine (the last coroutine switched to). The initial value
110is C<$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 try to do the same as calling exit 192Calling C<exit> in a coroutine will do the same as calling exit outside
191outside the coroutine, but this is experimental. It is best not to rely on 193the coroutine. Likewise, when the coroutine dies, the program will exit,
192exit doing any cleanups or even not crashing. 194just as it would in the main program.
193
194When the coroutine dies, the program will exit, just as in the main
195program.
196 195
197 # create a new coroutine that just prints its arguments 196 # create a new coroutine that just prints its arguments
198 async { 197 async {
199 print "@_\n"; 198 print "@_\n";
200 } 1,2,3,4; 199 } 1,2,3,4;
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231terminate }> once per second or so to slowly replenish the pool. 230terminate }> once per second or so to slowly replenish the pool.
232 231
233=cut 232=cut
234 233
235our $POOL_SIZE = 8; 234our $POOL_SIZE = 8;
235our $MAX_POOL_RSS = 64 * 1024;
236our @pool; 236our @pool;
237 237
238sub pool_handler { 238sub pool_handler {
239 while () { 239 while () {
240 $current->{desc} = "[async_pool]";
241
240 eval { 242 eval {
241 my ($cb, @arg) = @{ delete $current->{_invoke} or return }; 243 my ($cb, @arg) = @{ delete $current->{_invoke} or return };
242 $cb->(@arg); 244 $cb->(@arg);
243 }; 245 };
244 warn $@ if $@; 246 warn $@ if $@;
245 247
246 last if @pool >= $POOL_SIZE; 248 last if @pool >= $POOL_SIZE || $current->rss >= $MAX_POOL_RSS;
249
247 push @pool, $current; 250 push @pool, $current;
248 251 $current->{desc} = "[async_pool idle]";
249 $current->save (Coro::State::SAVE_DEF); 252 $current->save (Coro::State::SAVE_DEF);
250 $current->prio (0); 253 $current->prio (0);
251 schedule; 254 schedule;
252 } 255 }
253} 256}
254 257
255sub async_pool(&@) { 258sub async_pool(&@) {
256 # this is also inlined into the unlock_scheduler 259 # this is also inlined into the unlock_scheduler
257 my $coro = (pop @pool or new Coro \&pool_handler); 260 my $coro = (pop @pool) || new Coro \&pool_handler;;
258 261
259 $coro->{_invoke} = [@_]; 262 $coro->{_invoke} = [@_];
260 $coro->ready; 263 $coro->ready;
261 264
262 $coro 265 $coro
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280 # wake up sleeping coroutine 283 # wake up sleeping coroutine
281 $current->ready; 284 $current->ready;
282 undef $current; 285 undef $current;
283 }; 286 };
284 287
285 # call schedule until event occured. 288 # call schedule until event occurred.
286 # in case we are woken up for other reasons 289 # in case we are woken up for other reasons
287 # (current still defined), loop. 290 # (current still defined), loop.
288 Coro::schedule while $current; 291 Coro::schedule while $current;
289 } 292 }
290 293
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461=over 4 464=over 4
462 465
463=item Coro::nready 466=item Coro::nready
464 467
465Returns the number of coroutines that are currently in the ready state, 468Returns the number of coroutines that are currently in the ready state,
466i.e. that can be swicthed to. The value C<0> means that the only runnable 469i.e. that can be switched to. The value C<0> means that the only runnable
467coroutine is the currently running one, so C<cede> would have no effect, 470coroutine is the currently running one, so C<cede> would have no effect,
468and C<schedule> would cause a deadlock unless there is an idle handler 471and C<schedule> would cause a deadlock unless there is an idle handler
469that wakes up some coroutines. 472that wakes up some coroutines.
470 473
471=item my $guard = Coro::guard { ... } 474=item my $guard = Coro::guard { ... }
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507This utility function takes a BLOCK or code reference and "unblocks" it, 510This utility function takes a BLOCK or code reference and "unblocks" it,
508returning the new coderef. This means that the new coderef will return 511returning the new coderef. This means that the new coderef will return
509immediately without blocking, returning nothing, while the original code 512immediately without blocking, returning nothing, while the original code
510ref will be called (with parameters) from within its own coroutine. 513ref will be called (with parameters) from within its own coroutine.
511 514
512The reason this fucntion exists is that many event libraries (such as the 515The reason this function exists is that many event libraries (such as the
513venerable L<Event|Event> module) are not coroutine-safe (a weaker form 516venerable L<Event|Event> module) are not coroutine-safe (a weaker form
514of thread-safety). This means you must not block within event callbacks, 517of thread-safety). This means you must not block within event callbacks,
515otherwise you might suffer from crashes or worse. 518otherwise you might suffer from crashes or worse.
516 519
517This function allows your callbacks to block by executing them in another 520This function allows your callbacks to block by executing them in another
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528 531
529# we create a special coro because we want to cede, 532# we create a special coro because we want to cede,
530# to reduce pressure on the coro pool (because most callbacks 533# to reduce pressure on the coro pool (because most callbacks
531# return immediately and can be reused) and because we cannot cede 534# return immediately and can be reused) and because we cannot cede
532# inside an event callback. 535# inside an event callback.
533our $unblock_scheduler = async { 536our $unblock_scheduler = new Coro sub {
534 while () { 537 while () {
535 while (my $cb = pop @unblock_queue) { 538 while (my $cb = pop @unblock_queue) {
536 # this is an inlined copy of async_pool 539 # this is an inlined copy of async_pool
537 my $coro = (pop @pool or new Coro \&pool_handler); 540 my $coro = (pop @pool or new Coro \&pool_handler);
538 541
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541 cede; # for short-lived callbacks, this reduces pressure on the coro pool 544 cede; # for short-lived callbacks, this reduces pressure on the coro pool
542 } 545 }
543 schedule; # sleep well 546 schedule; # sleep well
544 } 547 }
545}; 548};
549$unblock_scheduler->desc ("[unblock_sub scheduler]");
546 550
547sub unblock_sub(&) { 551sub unblock_sub(&) {
548 my $cb = shift; 552 my $cb = shift;
549 553
550 sub { 554 sub {
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563 567
564 - you must make very sure that no coro is still active on global 568 - you must make very sure that no coro is still active on global
565 destruction. very bad things might happen otherwise (usually segfaults). 569 destruction. very bad things might happen otherwise (usually segfaults).
566 570
567 - this module is not thread-safe. You should only ever use this module 571 - this module is not thread-safe. You should only ever use this module
568 from the same thread (this requirement might be losened in the future 572 from the same thread (this requirement might be loosened in the future
569 to allow per-thread schedulers, but Coro::State does not yet allow 573 to allow per-thread schedulers, but Coro::State does not yet allow
570 this). 574 this).
571 575
572=head1 SEE ALSO 576=head1 SEE ALSO
573 577

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