[ViewVC] Diff of: cvs/Coro/Coro.pm

Comparing Coro/Coro.pm (file contents):
Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs.
Revision 1.134 by root, Sat Sep 22 14:42:56 2007 UTC

…		…
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 $VERSION = '3.7';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		62
…		…
108		108
109	The current coroutine (the last coroutine switched to). The initial value	109	The current coroutine (the last coroutine switched to). The initial value
110	is C<$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
		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
…		…
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
…		…
185		187
186	Create a new asynchronous coroutine and return it's coroutine object	188	Create 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
188	terminated.	190	terminated.
189		191
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	192	Calling C<exit> in a coroutine will do the same as calling exit outside
191		193	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	194	just as it would in the main program.
193	program.
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;
…		…
200	=cut	201	=cut
201		202
202	sub async(&@) {	203	sub async(&@) {
203	my $coro = new Coro @_;	204	my $coro = new Coro @_;
204	$coro->ready;	205	$coro->ready;
		206	$coro
		207	}
		208
		209	=item async_pool { ... } [@args...]
		210
		211	Similar to C<async>, but uses a coroutine pool, so you should not call
		212	terminate or join (although you are allowed to), and you get a coroutine
		213	that might have executed other code already (which can be good or bad :).
		214
		215	Also, the block is executed in an C<eval> context and a warning will be
		216	issued in case of an exception instead of terminating the program, as
		217	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		218	will not work in the expected way, unless you call terminate or cancel,
		219	which somehow defeats the purpose of pooling.
		220
		221	The priority will be reset to C<0> after each job, otherwise the coroutine
		222	will be re-used "as-is".
		223
		224	The pool size is limited to 8 idle coroutines (this can be adjusted by
		225	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		226	required.
		227
		228	If you are concerned about pooled coroutines growing a lot because a
		229	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		230	{ terminate }> once per second or so to slowly replenish the pool. In
		231	addition to that, when the stacks used by a handler grows larger than 16kb
		232	(adjustable with $Coro::POOL_RSS) it will also exit.
		233
		234	=cut
		235
		236	our $POOL_SIZE = 8;
		237	our $POOL_RSS = 16 * 1024;
		238	our @async_pool;
		239
		240	sub pool_handler {
		241	my $cb;
		242
		243	while () {
		244	eval {
		245	while () {
		246	$cb = &_pool_1
		247	or return;
		248
		249	&$cb;
		250
		251	return if &_pool_2;
		252
		253	undef $cb;
		254	schedule;
		255	}
		256	};
		257
		258	warn $@ if $@;
		259	}
		260	}
		261
		262	sub async_pool(&@) {
		263	# this is also inlined into the unlock_scheduler
		264	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;;
		265
		266	$coro->{_invoke} = [@_];
		267	$coro->ready;
		268
205	$coro	269	$coro
206	}	270	}
207		271
208	=item schedule	272	=item schedule
209		273
…		…
223	# wake up sleeping coroutine	287	# wake up sleeping coroutine
224	$current->ready;	288	$current->ready;
225	undef $current;	289	undef $current;
226	};	290	};
227		291
228	# call schedule until event occured.	292	# call schedule until event occurred.
229	# in case we are woken up for other reasons	293	# in case we are woken up for other reasons
230	# (current still defined), loop.	294	# (current still defined), loop.
231	Coro::schedule while $current;	295	Coro::schedule while $current;
232	}	296	}
233		297
…		…
235		299
236	"Cede" to other coroutines. This function puts the current coroutine into the	300	"Cede" to other coroutines. This function puts the current coroutine into the
237	ready queue and calls C<schedule>, which has the effect of giving up the	301	ready queue and calls C<schedule>, which has the effect of giving up the
238	current "timeslice" to other coroutines of the same or higher priority.	302	current "timeslice" to other coroutines of the same or higher priority.
239		303
		304	Returns true if at least one coroutine switch has happened.
		305
240	=item Coro::cede_notself	306	=item Coro::cede_notself
241		307
242	Works like cede, but is not exported by default and will cede to any	308	Works like cede, but is not exported by default and will cede to any
243	coroutine, regardless of priority, once.	309	coroutine, regardless of priority, once.
		310
		311	Returns true if at least one coroutine switch has happened.
244		312
245	=item terminate [arg...]	313	=item terminate [arg...]
246		314
247	Terminates the current coroutine with the given status values (see L<cancel>).	315	Terminates the current coroutine with the given status values (see L<cancel>).
248		316
…		…
267	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
268	automatically terminates as if C<terminate> with the returned values were	336	automatically terminates as if C<terminate> with the returned values were
269	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
270	by calling the ready method.	338	by calling the ready method.
271		339
272	Calling C<exit> in a coroutine will not work correctly, so do not do that.	340	See C<async> for additional discussion.
273		341
274	=cut	342	=cut
275		343
276	sub _run_coro {	344	sub _run_coro {
277	terminate &{+shift};	345	terminate &{+shift};
…		…
400	=over 4	468	=over 4
401		469
402	=item Coro::nready	470	=item Coro::nready
403		471
404	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,
405	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
406	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,
407	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
408	that wakes up some coroutines.	476	that wakes up some coroutines.
409		477
410	=item my $guard = Coro::guard { ... }	478	=item my $guard = Coro::guard { ... }
411		479
412	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
413	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
414	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
415	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
416	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,
417	C<< ->cancel >>, which will keep the codeblock from being executed.	485	C<< ->cancel >>, which will keep the codeblock from being executed.
…		…
446	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,
447	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
448	immediately without blocking, returning nothing, while the original code	516	immediately without blocking, returning nothing, while the original code
449	ref will be called (with parameters) from within its own coroutine.	517	ref will be called (with parameters) from within its own coroutine.
450		518
451	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
452	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
453	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,
454	otherwise you might suffer from crashes or worse.	522	otherwise you might suffer from crashes or worse.
455		523
456	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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461	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	529	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
462	creating event callbacks that want to block.	530	creating event callbacks that want to block.
463		531
464	=cut	532	=cut
465		533
466	our @unblock_pool;
467	our @unblock_queue;	534	our @unblock_queue;
468	our $UNBLOCK_POOL_SIZE = 2;
469		535
470	sub unblock_handler_ {	536	# we create a special coro because we want to cede,
471	while () {	537	# to reduce pressure on the coro pool (because most callbacks
472	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	538	# return immediately and can be reused) and because we cannot cede
473	$cb->(@arg);	539	# inside an event callback.
474
475	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
476	push @unblock_pool, $Coro::current;
477	schedule;
478	}
479	}
480
481	our $unblock_scheduler = async {	540	our $unblock_scheduler = new Coro sub {
482	while () {	541	while () {
483	while (my $cb = pop @unblock_queue) {	542	while (my $cb = pop @unblock_queue) {
484	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	543	# this is an inlined copy of async_pool
485	$handler->{arg} = $cb;	544	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		545
		546	$coro->{_invoke} = $cb;
486	$handler->ready;	547	$coro->ready;
487	cede;	548	cede; # for short-lived callbacks, this reduces pressure on the coro pool
488	}	549	}
489		550	schedule; # sleep well
490	schedule;
491	}	551	}
492	};	552	};
		553	$unblock_scheduler->desc ("[unblock_sub scheduler]");
493		554
494	sub unblock_sub(&) {	555	sub unblock_sub(&) {
495	my $cb = shift;	556	my $cb = shift;
496		557
497	sub {	558	sub {
498	push @unblock_queue, [$cb, @_];	559	unshift @unblock_queue, [$cb, @_];
499	$unblock_scheduler->ready;	560	$unblock_scheduler->ready;
500	}	561	}
501	}	562	}
502		563
503	=back	564	=back
…		…
510		571
511	- 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
512	destruction. very bad things might happen otherwise (usually segfaults).	573	destruction. very bad things might happen otherwise (usually segfaults).
513		574
514	- 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
515	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
516	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
517	this).	578	this).
518		579
519	=head1 SEE ALSO	580	=head1 SEE ALSO
520		581

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Comparing Coro/Coro.pm (file contents): Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs. Revision 1.134 by root, Sat Sep 22 14:42:56 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs.
Revision 1.134 by root, Sat Sep 22 14:42:56 2007 UTC