[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs.
Revision 1.74 by root, Tue Oct 24 17:22:17 2006 UTC

…		…
51	=head1 DESCRIPTION	51	=head1 DESCRIPTION
52		52
53	This module implements asynchronous I/O using whatever means your	53	This module implements asynchronous I/O using whatever means your
54	operating system supports.	54	operating system supports.
55		55
56	Currently, a number of threads are started that execute your read/writes	56	In this version, a number of threads are started that execute your
57	and signal their completion. You don't need thread support in perl, and	57	requests and signal their completion. You don't need thread support
58	the threads created by this module will not be visible to perl. In the	58	in perl, and the threads created by this module will not be visible
59	future, this module might make use of the native aio functions available	59	to perl. In the future, this module might make use of the native aio
60	on many operating systems. However, they are often not well-supported	60	functions available on many operating systems. However, they are often
61	(Linux doesn't allow them on normal files currently, for example),	61	not well-supported or restricted (Linux doesn't allow them on normal
62	and they would only support aio_read and aio_write, so the remaining	62	files currently, for example), and they would only support aio_read and
63	functionality would have to be implemented using threads anyway.	63	aio_write, so the remaining functionality would have to be implemented
		64	using threads anyway.
64		65
65	Although the module will work with in the presence of other threads,	66	Although the module will work with in the presence of other (Perl-)
66	it is currently not reentrant in any way, so use appropriate locking	67	threads, it is currently not reentrant in any way, so use appropriate
67	yourself, always call C<poll_cb> from within the same thread, or never	68	locking yourself, always call C<poll_cb> from within the same thread, or
68	call C<poll_cb> (or other C<aio_> functions) recursively.	69	never call C<poll_cb> (or other C<aio_> functions) recursively.
		70
		71	=head1 REQUEST ANATOMY AND LIFETIME
		72
		73	Every C<aio_*> function creates a request. which is a C data structure not
		74	directly visible to Perl.
		75
		76	If called in non-void context, every request function returns a Perl
		77	object representing the request. In void context, nothing is returned,
		78	which saves a bit of memory.
		79
		80	The perl object is a fairly standard ref-to-hash object. The hash contents
		81	are not used by IO::AIO so you are free to store anything you like in it.
		82
		83	During their existance, aio requests travel through the following states,
		84	in order:
		85
		86	=over 4
		87
		88	=item ready
		89
		90	Immediately after a request is created it is put into the ready state,
		91	waiting for a thread to execute it.
		92
		93	=item execute
		94
		95	A thread has accepted the request for processing and is currently
		96	executing it (e.g. blocking in read).
		97
		98	=item pending
		99
		100	The request has been executed and is waiting for result processing.
		101
		102	While request submission and execution is fully asynchronous, result
		103	processing is not and relies on the perl interpreter calling C<poll_cb>
		104	(or another function with the same effect).
		105
		106	=item result
		107
		108	The request results are processed synchronously by C<poll_cb>.
		109
		110	The C<poll_cb> function will process all outstanding aio requests by
		111	calling their callbacks, freeing memory associated with them and managing
		112	any groups they are contained in.
		113
		114	=item done
		115
		116	Request has reached the end of its lifetime and holds no resources anymore
		117	(except possibly for the Perl object, but its connection to the actual
		118	aio request is severed and calling its methods will either do nothing or
		119	result in a runtime error).
69		120
70	=cut	121	=cut
71		122
72	package IO::AIO;	123	package IO::AIO;
73		124
…		…
469	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	520	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
470	@$entries];	521	@$entries];
471		522
472	my (@dirs, @nondirs);	523	my (@dirs, @nondirs);
473		524
474	my ($statcb, $schedcb);
475	my $nreq = 0;
476
477	my $statgrp = add $grp aio_group;	525	my $statgrp = add $grp aio_group sub {
		526	$grp->result (\@dirs, \@nondirs);
		527	};
478		528
479	$schedcb = sub {	529	limit $statgrp $maxreq;
480	if (@$entries) {	530	feed $statgrp sub {
481	if ($nreq < $maxreq) {	531	return unless @$entries;
482	my $ent = pop @$entries;	532	my $entry = pop @$entries;
		533
		534	add $statgrp aio_stat "$path/$entry/.", sub {
		535	if ($_[0] < 0) {
		536	push @nondirs, $entry;
		537	} else {
		538	# need to check for real directory
		539	add $statgrp aio_lstat "$path/$entry", sub {
		540	if (-d _) {
		541	push @dirs, $entry;
		542
		543	if (!--$ndirs) {
		544	push @nondirs, @$entries;
		545	$statgrp->cancel_subs;
		546	}
		547	} else {
		548	push @nondirs, $entry;
		549	}
483	$nreq++;	550	}
484	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
485	}	551	}
486	} elsif (!$nreq) {
487	# finished
488	$statgrp->cancel;
489	undef $statcb;
490	undef $schedcb;
491	$grp->result (\@dirs, \@nondirs);
492	}	552	};
493	};	553	};
494	$statcb = sub {
495	my ($status, $entry) = @_;
496
497	if ($status < 0) {
498	$nreq--;
499	push @nondirs, $entry;
500	&$schedcb;
501	} else {
502	# need to check for real directory
503	add $grp aio_lstat "$path/$entry", sub {
504	$nreq--;
505
506	if (-d _) {
507	push @dirs, $entry;
508
509	if (!--$ndirs) {
510	push @nondirs, @$entries;
511	$entries = [];
512	}
513	} else {
514	push @nondirs, $entry;
515	}
516
517	&$schedcb;
518	}
519	}
520	};
521
522	&$schedcb while @$entries && $nreq < $maxreq;
523	};	554	};
524	};	555	};
525	};	556	};
526		557
527	$grp	558	$grp
…		…
539		570
540	If this call isn't available because your OS lacks it or it couldn't be	571	If this call isn't available because your OS lacks it or it couldn't be
541	detected, it will be emulated by calling C<fsync> instead.	572	detected, it will be emulated by calling C<fsync> instead.
542		573
543	=item aio_group $callback->(...)	574	=item aio_group $callback->(...)
544
545	[EXPERIMENTAL]
546		575
547	This is a very special aio request: Instead of doing something, it is a	576	This is a very special aio request: Instead of doing something, it is a
548	container for other aio requests, which is useful if you want to bundle	577	container for other aio requests, which is useful if you want to bundle
549	many requests into a single, composite, request with a definite callback	578	many requests into a single, composite, request with a definite callback
550	and the ability to cancel the whole request with its subrequests.	579	and the ability to cancel the whole request with its subrequests.
…		…
591	=head2 IO::AIO::REQ CLASS	620	=head2 IO::AIO::REQ CLASS
592		621
593	All non-aggregate C<aio_*> functions return an object of this class when	622	All non-aggregate C<aio_*> functions return an object of this class when
594	called in non-void context.	623	called in non-void context.
595		624
596	A request always moves through the following five states in its lifetime,
597	in order: B<ready> (request has been created, but has not been executed
598	yet), B<execute> (request is currently being executed), B<pending>
599	(request has been executed but callback has not been called yet),
600	B<result> (results are being processed synchronously, includes calling the
601	callback) and B<done> (request has reached the end of its lifetime and
602	holds no resources anymore).
603
604	=over 4	625	=over 4
605		626
606	=item cancel $req	627	=item cancel $req
607		628
608	Cancels the request, if possible. Has the effect of skipping execution	629	Cancels the request, if possible. Has the effect of skipping execution
…		…
689	be added, including other groups, as long as you do not create circular	710	be added, including other groups, as long as you do not create circular
690	dependencies.	711	dependencies.
691		712
692	Returns all its arguments.	713	Returns all its arguments.
693		714
		715	=item $grp->cancel_subs
		716
		717	Cancel all subrequests and clears any feeder, but not the group request
		718	itself. Useful when you queued a lot of events but got a result early.
		719
694	=item $grp->result (...)	720	=item $grp->result (...)
695		721
696	Set the result value(s) that will be passed to the group callback when all	722	Set the result value(s) that will be passed to the group callback when all
697	subrequests have finished. By default, no argument will be passed.	723	subrequests have finished. By default, no argument will be passed.
698		724
699	=item feed $grp $callback->($grp)	725	=item feed $grp $callback->($grp)
700
701	[VERY EXPERIMENTAL]
702		726
703	Sets a feeder/generator on this group: every group can have an attached	727	Sets a feeder/generator on this group: every group can have an attached
704	generator that generates requests if idle. The idea behind this is that,	728	generator that generates requests if idle. The idea behind this is that,
705	although you could just queue as many requests as you want in a group,	729	although you could just queue as many requests as you want in a group,
706	this might starve other requests for a potentially long time. For	730	this might starve other requests for a potentially long time. For
…		…
888	This module should do "the right thing" when the process using it forks:	912	This module should do "the right thing" when the process using it forks:
889		913
890	Before the fork, IO::AIO enters a quiescent state where no requests	914	Before the fork, IO::AIO enters a quiescent state where no requests
891	can be added in other threads and no results will be processed. After	915	can be added in other threads and no results will be processed. After
892	the fork the parent simply leaves the quiescent state and continues	916	the fork the parent simply leaves the quiescent state and continues
893	request/result processing, while the child clears the request/result	917	request/result processing, while the child frees the request/result queue
894	queue (so the requests started before the fork will only be handled in	918	(so that the requests started before the fork will only be handled in the
895	the parent). Threads will be started on demand until the limit ste in the	919	parent). Threads will be started on demand until the limit set in the
896	parent process has been reached again.	920	parent process has been reached again.
897		921
898	In short: the parent will, after a short pause, continue as if fork had	922	In short: the parent will, after a short pause, continue as if fork had
899	not been called, while the child will act as if IO::AIO has not been used	923	not been called, while the child will act as if IO::AIO has not been used
900	yet.	924	yet.
901		925
902	=head2 MEMORY USAGE	926	=head2 MEMORY USAGE
903		927
		928	Per-request usage:
		929
904	Each aio request uses - depending on your architecture - around 128 bytes	930	Each aio request uses - depending on your architecture - around 100-200
905	of memory. In addition, stat requests need a stat buffer (possibly a few	931	bytes of memory. In addition, stat requests need a stat buffer (possibly
906	hundred bytes). Perl scalars and other data passed into aio requests will	932	a few hundred bytes), readdir requires a result buffer and so on. Perl
907	also be locked.	933	scalars and other data passed into aio requests will also be locked and
		934	will consume memory till the request has entered the done state.
908		935
909	This is now awfully much, so queuing lots of requests is not usually a	936	This is now awfully much, so queuing lots of requests is not usually a
910	problem.	937	problem.
911		938
912	Each thread needs a stack area which is usually around 16k, sometimes much	939	Per-thread usage:
913	larger, depending on the OS.	940
		941	In the execution phase, some aio requests require more memory for
		942	temporary buffers, and each thread requires a stack and other data
		943	structures (usually around 16k-128k, depending on the OS).
		944
		945	=head1 KNOWN BUGS
		946
		947	Known bugs will be fixed in the next release.
914		948
915	=head1 SEE ALSO	949	=head1 SEE ALSO
916		950
917	L<Coro::AIO>.	951	L<Coro::AIO>.
918		952

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs. Revision 1.74 by root, Tue Oct 24 17:22:17 2006 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs.
Revision 1.74 by root, Tue Oct 24 17:22:17 2006 UTC