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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.55 by root, Sun Oct 22 00:49:29 2006 UTC vs.
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC

…		…
15		15
16	aio_read $fh, 30000, 1024, $buffer, 0, sub {	16	aio_read $fh, 30000, 1024, $buffer, 0, sub {
17	$_[0] > 0 or die "read error: $!";	17	$_[0] > 0 or die "read error: $!";
18	};	18	};
19		19
20	use IO::AIO 2; # version has aio objects	20	# version 2+ has request and group objects
		21	use IO::AIO 2;
21		22
		23	aioreq_pri 4; # give next request a very high priority
22	my $req = aio_unlink "/tmp/file", sub { };	24	my $req = aio_unlink "/tmp/file", sub { };
23	$req->cancel; # cancel request if still in queue	25	$req->cancel; # cancel request if still in queue
24		26
25	# AnyEvent	27	my $grp = aio_group sub { print "all stats done\n" };
		28	add $grp aio_stat "..." for ...;
		29
		30	# AnyEvent integration
26	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";	31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
27	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });	32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
28		33
29	# Event	34	# Event integration
30	Event->io (fd => IO::AIO::poll_fileno,	35	Event->io (fd => IO::AIO::poll_fileno,
31	poll => 'r',	36	poll => 'r',
32	cb => \&IO::AIO::poll_cb);	37	cb => \&IO::AIO::poll_cb);
33		38
34	# Glib/Gtk2	39	# Glib/Gtk2 integration
35	add_watch Glib::IO IO::AIO::poll_fileno,	40	add_watch Glib::IO IO::AIO::poll_fileno,
36	in => sub { IO::AIO::poll_cb; 1 };	41	in => sub { IO::AIO::poll_cb; 1 };
37		42
38	# Tk	43	# Tk integration
39	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",	44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
40	readable => \&IO::AIO::poll_cb);	45	readable => \&IO::AIO::poll_cb);
41		46
42	# Danga::Socket	47	# Danga::Socket integration
43	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
44	\&IO::AIO::poll_cb);	49	\&IO::AIO::poll_cb);
45		50
46
47	=head1 DESCRIPTION	51	=head1 DESCRIPTION
48		52
49	This module implements asynchronous I/O using whatever means your	53	This module implements asynchronous I/O using whatever means your
50	operating system supports.	54	operating system supports.
51		55
52	Currently, a number of threads are started that execute your read/writes	56	Currently, a number of threads are started that execute your read/writes
53	and signal their completion. You don't need thread support in your libc or	57	and signal their completion. You don't need thread support in perl, and
54	perl, and the threads created by this module will not be visible to the	58	the threads created by this module will not be visible to perl. In the
55	pthreads library. In the future, this module might make use of the native	59	future, this module might make use of the native aio functions available
56	aio functions available on many operating systems. However, they are often	60	on many operating systems. However, they are often not well-supported
57	not well-supported (Linux doesn't allow them on normal files currently,	61	(Linux doesn't allow them on normal files currently, for example),
58	for example), and they would only support aio_read and aio_write, so the	62	and they would only support aio_read and aio_write, so the remaining
59	remaining functionality would have to be implemented using threads anyway.	63	functionality would have to be implemented using threads anyway.
60		64
61	Although the module will work with in the presence of other threads, it is	65	Although the module will work with in the presence of other threads,
62	currently not reentrant, so use appropriate locking yourself, always call	66	it is currently not reentrant in any way, so use appropriate locking
63	C<poll_cb> from within the same thread, or never call C<poll_cb> (or other	67	yourself, always call C<poll_cb> from within the same thread, or never
64	C<aio_> functions) recursively.	68	call C<poll_cb> (or other C<aio_> functions) recursively.
65		69
66	=cut	70	=cut
67		71
68	package IO::AIO;	72	package IO::AIO;
69		73
…		…
73	use base 'Exporter';	77	use base 'Exporter';
74		78
75	BEGIN {	79	BEGIN {
76	our $VERSION = '2.0';	80	our $VERSION = '2.0';
77		81
78	our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	82	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
79	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	83	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
80	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	84	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
81	aio_group);	85	aio_group aio_nop);
82	our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	86	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
		87	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
		88	min_parallel max_parallel max_outstanding nreqs);
83		89
84	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	90	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
85		91
86	require XSLoader;	92	require XSLoader;
87	XSLoader::load ("IO::AIO", $VERSION);	93	XSLoader::load ("IO::AIO", $VERSION);
…		…
118	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	124	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
119	use something else.	125	use something else.
120		126
121	=over 4	127	=over 4
122		128
		129	=item aioreq_pri $pri
		130
		131	Sets the priority for the next aio request. The default priority
		132	is C<0>, the minimum and maximum priorities are C<-4> and C<4>,
		133	respectively. Requests with higher priority will be serviced first.
		134
		135	The priority will be reset to C<0> after each call to one of the C<aio_>
		136	functions.
		137
		138	Example: open a file with low priority, then read something from it with
		139	higher priority so the read request is serviced before other low priority
		140	open requests (potentially spamming the cache):
		141
		142	aioreq_pri -3;
		143	aio_open ..., sub {
		144	return unless $_[0];
		145
		146	aioreq_pri -2;
		147	aio_read $_[0], ..., sub {
		148	...
		149	};
		150	};
		151
		152	=item aioreq_nice $pri_adjust
		153
		154	Similar to C<aioreq_pri>, but subtracts the given value from the current
		155	priority, so effects are cumulative.
		156
123	=item aio_open $pathname, $flags, $mode, $callback->($fh)	157	=item aio_open $pathname, $flags, $mode, $callback->($fh)
124		158
125	Asynchronously open or create a file and call the callback with a newly	159	Asynchronously open or create a file and call the callback with a newly
126	created filehandle for the file.	160	created filehandle for the file.
127		161
…		…
198	=cut	232	=cut
199		233
200	sub aio_move($$$) {	234	sub aio_move($$$) {
201	my ($src, $dst, $cb) = @_;	235	my ($src, $dst, $cb) = @_;
202		236
203	my $grp = aio_group;	237	my $grp = aio_group $cb;
204		238
205	add $grp aio_rename $src, $dst, sub {	239	add $grp aio_rename $src, $dst, sub {
206	if ($_[0] && $! == EXDEV) {	240	if ($_[0] && $! == EXDEV) {
207	add $grp aio_open $src, O_RDONLY, 0, sub {	241	add $grp aio_open $src, O_RDONLY, 0, sub {
208	if (my $src_fh = $_[0]) {	242	if (my $src_fh = $_[0]) {
…		…
218	chmod $stat[2] & 07777, $dst_fh;	252	chmod $stat[2] & 07777, $dst_fh;
219	chown $stat[4], $stat[5], $dst_fh;	253	chown $stat[4], $stat[5], $dst_fh;
220	close $dst_fh;	254	close $dst_fh;
221		255
222	add $grp aio_unlink $src, sub {	256	add $grp aio_unlink $src, sub {
223	$cb->($_[0]);	257	$grp->result ($_[0]);
224	};	258	};
225	} else {	259	} else {
226	my $errno = $!;	260	my $errno = $!;
227	add $grp aio_unlink $dst, sub {	261	add $grp aio_unlink $dst, sub {
228	$! = $errno;	262	$! = $errno;
229	$cb->(-1);	263	$grp->result (-1);
230	};	264	};
231	}	265	}
232	};	266	};
233	} else {	267	} else {
234	$cb->(-1);	268	$grp->result (-1);
235	}	269	}
236	},	270	},
237		271
238	} else {	272	} else {
239	$cb->(-1);	273	$grp->result (-1);
240	}	274	}
241	};	275	};
242	} else {	276	} else {
243	$cb->($_[0]);	277	$grp->result ($_[0]);
244	}	278	}
245	};	279	};
246		280
247	$grp	281	$grp
248	}	282	}
…		…
345	Scans a directory (similar to C<aio_readdir>) but additionally tries to	379	Scans a directory (similar to C<aio_readdir>) but additionally tries to
346	separate the entries of directory C<$path> into two sets of names, ones	380	separate the entries of directory C<$path> into two sets of names, ones
347	you can recurse into (directories or links to them), and ones you cannot	381	you can recurse into (directories or links to them), and ones you cannot
348	recurse into (everything else).	382	recurse into (everything else).
349		383
350	C<aio_scandir> is a composite request that consists of many sub	384	C<aio_scandir> is a composite request that creates of many sub requests_
351	requests. C<$maxreq> specifies the maximum number of outstanding aio	385	C<$maxreq> specifies the maximum number of outstanding aio requests that
352	requests that this function generates. If it is C<< <= 0 >>, then a	386	this function generates. If it is C<< <= 0 >>, then a suitable default
353	suitable default will be chosen (currently 8).	387	will be chosen (currently 6).
354		388
355	On error, the callback is called without arguments, otherwise it receives	389	On error, the callback is called without arguments, otherwise it receives
356	two array-refs with path-relative entry names.	390	two array-refs with path-relative entry names.
357		391
358	Example:	392	Example:
…		…
395	=cut	429	=cut
396		430
397	sub aio_scandir($$$) {	431	sub aio_scandir($$$) {
398	my ($path, $maxreq, $cb) = @_;	432	my ($path, $maxreq, $cb) = @_;
399		433
400	my $grp = aio_group;	434	my $grp = aio_group $cb;
401		435
402	$maxreq = 8 if $maxreq <= 0;	436	$maxreq = 6 if $maxreq <= 0;
403		437
404	# stat once	438	# stat once
405	add $grp aio_stat $path, sub {	439	add $grp aio_stat $path, sub {
406	return $cb->() if $_[0];	440	return $grp->result () if $_[0];
407	my $now = time;	441	my $now = time;
408	my $hash1 = join ":", (stat _)[0,1,3,7,9];	442	my $hash1 = join ":", (stat _)[0,1,3,7,9];
409		443
410	# read the directory entries	444	# read the directory entries
411	add $grp aio_readdir $path, sub {	445	add $grp aio_readdir $path, sub {
412	my $entries = shift	446	my $entries = shift
413	or return $cb->();	447	or return $grp->result ();
414		448
415	# stat the dir another time	449	# stat the dir another time
416	add $grp aio_stat $path, sub {	450	add $grp aio_stat $path, sub {
417	my $hash2 = join ":", (stat _)[0,1,3,7,9];	451	my $hash2 = join ":", (stat _)[0,1,3,7,9];
418		452
…		…
423	$ndirs = -1;	457	$ndirs = -1;
424	} else {	458	} else {
425	# if nlink == 2, we are finished	459	# if nlink == 2, we are finished
426	# on non-posix-fs's, we rely on nlink < 2	460	# on non-posix-fs's, we rely on nlink < 2
427	$ndirs = (stat _)[3] - 2	461	$ndirs = (stat _)[3] - 2
428	or return $cb->([], $entries);	462	or return $grp->result ([], $entries);
429	}	463	}
430		464
431	# sort into likely dirs and likely nondirs	465	# sort into likely dirs and likely nondirs
432	# dirs == files without ".", short entries first	466	# dirs == files without ".", short entries first
433	$entries = [map $_->[0],	467	$entries = [map $_->[0],
…		…
438	my (@dirs, @nondirs);	472	my (@dirs, @nondirs);
439		473
440	my ($statcb, $schedcb);	474	my ($statcb, $schedcb);
441	my $nreq = 0;	475	my $nreq = 0;
442		476
		477	my $statgrp = add $grp aio_group;
		478
443	$schedcb = sub {	479	$schedcb = sub {
444	if (@$entries) {	480	if (@$entries) {
445	if ($nreq < $maxreq) {	481	if ($nreq < $maxreq) {
446	my $ent = pop @$entries;	482	my $ent = pop @$entries;
447	$nreq++;	483	$nreq++;
448	add $grp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };	484	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
449	}	485	}
450	} elsif (!$nreq) {	486	} elsif (!$nreq) {
451	# finished	487	# finished
		488	$statgrp->cancel;
452	undef $statcb;	489	undef $statcb;
453	undef $schedcb;	490	undef $schedcb;
454	$cb->(\@dirs, \@nondirs) if $cb;	491	$grp->result (\@dirs, \@nondirs);
455	undef $cb;
456	}	492	}
457	};	493	};
458	$statcb = sub {	494	$statcb = sub {
459	my ($status, $entry) = @_;	495	my ($status, $entry) = @_;
460		496
…		…
502	callback with the fdatasync result code.	538	callback with the fdatasync result code.
503		539
504	If this call isn't available because your OS lacks it or it couldn't be	540	If this call isn't available because your OS lacks it or it couldn't be
505	detected, it will be emulated by calling C<fsync> instead.	541	detected, it will be emulated by calling C<fsync> instead.
506		542
507	=item aio_group $callback->()	543	=item aio_group $callback->(...)
508		544
509	[EXPERIMENTAL]	545	[EXPERIMENTAL]
510		546
511	This is a very special aio request: Instead of doing something, it is a	547	This is a very special aio request: Instead of doing something, it is a
512	container for other aio requests, which is useful if you want to bundle	548	container for other aio requests, which is useful if you want to bundle
513	many requests into a single, composite, request.	549	many requests into a single, composite, request with a definite callback
		550	and the ability to cancel the whole request with its subrequests.
514		551
515	Returns an object of class L<IO::AIO::GRP>. See its documentation below	552	Returns an object of class L<IO::AIO::GRP>. See its documentation below
516	for more info.	553	for more info.
517		554
518	Example:	555	Example:
…		…
524	add $grp	561	add $grp
525	(aio_stat ...),	562	(aio_stat ...),
526	(aio_stat ...),	563	(aio_stat ...),
527	...;	564	...;
528		565
		566	=item aio_nop $callback->()
		567
		568	This is a special request - it does nothing in itself and is only used for
		569	side effects, such as when you want to add a dummy request to a group so
		570	that finishing the requests in the group depends on executing the given
		571	code.
		572
		573	While this request does nothing, it still goes through the execution
		574	phase and still requires a worker thread. Thus, the callback will not
		575	be executed immediately but only after other requests in the queue have
		576	entered their execution phase. This can be used to measure request
		577	latency.
		578
529	=item aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	579	=item IO::AIO::aio_busy $fractional_seconds, $callback->() NOT EXPORTED
530		580
531	Mainly used for debugging and benchmarking, this aio request puts one of	581	Mainly used for debugging and benchmarking, this aio request puts one of
532	the request workers to sleep for the given time.	582	the request workers to sleep for the given time.
		583
		584	While it is theoretically handy to have simple I/O scheduling requests
		585	like sleep and file handle readable/writable, the overhead this creates is
		586	immense (it blocks a thread for a long time) so do not use this function
		587	except to put your application under artificial I/O pressure.
533		588
534	=back	589	=back
535		590
536	=head2 IO::AIO::REQ CLASS	591	=head2 IO::AIO::REQ CLASS
537		592
…		…
546	callback) and B<done> (request has reached the end of its lifetime and	601	callback) and B<done> (request has reached the end of its lifetime and
547	holds no resources anymore).	602	holds no resources anymore).
548		603
549	=over 4	604	=over 4
550		605
551	=item $req->cancel	606	=item cancel $req
552		607
553	Cancels the request, if possible. Has the effect of skipping execution	608	Cancels the request, if possible. Has the effect of skipping execution
554	when entering the B<execute> state and skipping calling the callback when	609	when entering the B<execute> state and skipping calling the callback when
555	entering the the B<result> state, but will leave the request otherwise	610	entering the the B<result> state, but will leave the request otherwise
556	untouched. That means that requests that currently execute will not be	611	untouched. That means that requests that currently execute will not be
557	stopped and resources held by the request will not be freed prematurely.	612	stopped and resources held by the request will not be freed prematurely.
558		613
		614	=item cb $req $callback->(...)
		615
		616	Replace (or simply set) the callback registered to the request.
		617
559	=back	618	=back
560		619
561	=head2 IO::AIO::GRP CLASS	620	=head2 IO::AIO::GRP CLASS
562		621
563	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to	622	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to
…		…
577	You add requests by calling the C<add> method with one or more	636	You add requests by calling the C<add> method with one or more
578	C<IO::AIO::REQ> objects:	637	C<IO::AIO::REQ> objects:
579		638
580	$grp->add (aio_unlink "...");	639	$grp->add (aio_unlink "...");
581		640
582	add $grp aio_stat "...", sub { ... };	641	add $grp aio_stat "...", sub {
		642	$_[0] or return $grp->result ("error");
		643
		644	# add another request dynamically, if first succeeded
		645	add $grp aio_open "...", sub {
		646	$grp->result ("ok");
		647	};
		648	};
583		649
584	This makes it very easy to create composite requests (see the source of	650	This makes it very easy to create composite requests (see the source of
585	C<aio_move> for an application) that work and feel like simple requests.	651	C<aio_move> for an application) that work and feel like simple requests.
586		652
		653	=over 4
		654
587	The IO::AIO::GRP objects will be cleaned up during calls to	655	=item * The IO::AIO::GRP objects will be cleaned up during calls to
588	C<IO::AIO::poll_cb>, just like any other request.	656	C<IO::AIO::poll_cb>, just like any other request.
589		657
590	They can be canceled like any other request. Canceling will cancel not	658	=item * They can be canceled like any other request. Canceling will cancel not
591	just the request itself, but also all requests it contains.	659	only the request itself, but also all requests it contains.
592		660
593	They can also can also be added to other IO::AIO::GRP objects.	661	=item * They can also can also be added to other IO::AIO::GRP objects.
		662
		663	=item * You must not add requests to a group from within the group callback (or
		664	any later time).
		665
		666	=item * This does not harmonise well with C<max_outstanding>, so best do
		667	not combine C<aio_group> with it. Groups and feeders are recommended for
		668	this kind of concurrency-limiting.
		669
		670	=back
594		671
595	Their lifetime, simplified, looks like this: when they are empty, they	672	Their lifetime, simplified, looks like this: when they are empty, they
596	will finish very quickly. If they contain only requests that are in the	673	will finish very quickly. If they contain only requests that are in the
597	C<done> state, they will also finish. Otherwise they will continue to	674	C<done> state, they will also finish. Otherwise they will continue to
598	exist.	675	exist.
599		676
		677	That means after creating a group you have some time to add requests. And
		678	in the callbacks of those requests, you can add further requests to the
		679	group. And only when all those requests have finished will the the group
		680	itself finish.
		681
600	=over 4	682	=over 4
601		683
		684	=item add $grp ...
		685
602	=item $grp->add (...)	686	=item $grp->add (...)
603		687
604	=item add $grp ...	688	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
		689	be added, including other groups, as long as you do not create circular
		690	dependencies.
605		691
606	Add one or more	692	Returns all its arguments.
607	Cancels the request, if possible. Has the effect of skipping execution	693
608	when entering the B<execute> state and skipping calling the callback when	694	=item $grp->result (...)
609	entering the the B<result> state, but will leave the request otherwise	695
610	untouched. That means that requests that currently execute will not be	696	Set the result value(s) that will be passed to the group callback when all
611	stopped and resources held by the request will not be freed prematurely.	697	subrequests have finished. By default, no argument will be passed.
		698
		699	=item feed $grp $callback->($grp)
		700
		701	[VERY EXPERIMENTAL]
		702
		703	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,
		705	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
		707	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
		708	requests, delaying any later requests for a long time.
		709
		710	To avoid this, and allow incremental generation of requests, you can
		711	instead a group and set a feeder on it that generates those requests. The
		712	feed callback will be called whenever there are few enough (see C<limit>,
		713	below) requests active in the group itself and is expected to queue more
		714	requests.
		715
		716	The feed callback can queue as many requests as it likes (i.e. C<add> does
		717	not impose any limits).
		718
		719	If the feed does not queue more requests when called, it will be
		720	automatically removed from the group.
		721
		722	If the feed limit is C<0>, it will be set to C<2> automatically.
		723
		724	Example:
		725
		726	# stat all files in @files, but only ever use four aio requests concurrently:
		727
		728	my $grp = aio_group sub { print "finished\n" };
		729	limit $grp 4;
		730	feed $grp sub {
		731	my $file = pop @files
		732	or return;
		733
		734	add $grp aio_stat $file, sub { ... };
		735	};
		736
		737	=item limit $grp $num
		738
		739	Sets the feeder limit for the group: The feeder will be called whenever
		740	the group contains less than this many requests.
		741
		742	Setting the limit to C<0> will pause the feeding process.
612		743
613	=back	744	=back
614		745
615	=head2 SUPPORT FUNCTIONS	746	=head2 SUPPORT FUNCTIONS
616		747
…		…
674	IO::AIO::poll_wait, IO::AIO::poll_cb	805	IO::AIO::poll_wait, IO::AIO::poll_cb
675	if IO::AIO::nreqs;	806	if IO::AIO::nreqs;
676		807
677	=item IO::AIO::min_parallel $nthreads	808	=item IO::AIO::min_parallel $nthreads
678		809
679	Set the minimum number of AIO threads to C<$nthreads>. The current default	810	Set the minimum number of AIO threads to C<$nthreads>. The current
680	is C<4>, which means four asynchronous operations can be done at one time	811	default is C<8>, which means eight asynchronous operations can execute
681	(the number of outstanding operations, however, is unlimited).	812	concurrently at any one time (the number of outstanding requests,
		813	however, is unlimited).
682		814
683	IO::AIO starts threads only on demand, when an AIO request is queued and	815	IO::AIO starts threads only on demand, when an AIO request is queued and
684	no free thread exists.	816	no free thread exists.
685		817
686	It is recommended to keep the number of threads low, as some Linux	818	It is recommended to keep the number of threads relatively low, as some
687	kernel versions will scale negatively with the number of threads (higher	819	Linux kernel versions will scale negatively with the number of threads
688	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	820	(higher parallelity => MUCH higher latency). With current Linux 2.6
689	threads should be fine.	821	versions, 4-32 threads should be fine.
690		822
691	Under most circumstances you don't need to call this function, as the	823	Under most circumstances you don't need to call this function, as the
692	module selects a default that is suitable for low to moderate load.	824	module selects a default that is suitable for low to moderate load.
693		825
694	=item IO::AIO::max_parallel $nthreads	826	=item IO::AIO::max_parallel $nthreads
…		…
705		837
706	Under normal circumstances you don't need to call this function.	838	Under normal circumstances you don't need to call this function.
707		839
708	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	840	=item $oldnreqs = IO::AIO::max_outstanding $nreqs
709		841
		842	[DEPRECATED]
		843
710	Sets the maximum number of outstanding requests to C<$nreqs>. If you	844	Sets the maximum number of outstanding requests to C<$nreqs>. If you
711	try to queue up more than this number of requests, the caller will block until	845	try to queue up more than this number of requests, the caller will block until
712	some requests have been handled.	846	some requests have been handled.
713		847
714	The default is very large, so normally there is no practical limit. If you	848	The default is very large, so normally there is no practical limit. If you
715	queue up many requests in a loop it often improves speed if you set	849	queue up many requests in a loop it often improves speed if you set
716	this to a relatively low number, such as C<100>.	850	this to a relatively low number, such as C<100>.
		851
		852	This function does not work well together with C<aio_group>'s, and their
		853	feeder interface is better suited to limiting concurrency, so do not use
		854	this function.
717		855
718	Under normal circumstances you don't need to call this function.	856	Under normal circumstances you don't need to call this function.
719		857
720	=back	858	=back
721		859
…		…
735	or return undef;	873	or return undef;
736		874
737	*$sym	875	*$sym
738	}	876	}
739		877
740	min_parallel 4;	878	min_parallel 8;
741		879
742	END {	880	END {
743	max_parallel 0;	881	max_parallel 0;
744	}	882	}
745		883
…		…
759		897
760	In short: the parent will, after a short pause, continue as if fork had	898	In short: the parent will, after a short pause, continue as if fork had
761	not been called, while the child will act as if IO::AIO has not been used	899	not been called, while the child will act as if IO::AIO has not been used
762	yet.	900	yet.
763		901
		902	=head2 MEMORY USAGE
		903
		904	Each aio request uses - depending on your architecture - around 128 bytes
		905	of memory. In addition, stat requests need a stat buffer (possibly a few
		906	hundred bytes). Perl scalars and other data passed into aio requests will
		907	also be locked.
		908
		909	This is now awfully much, so queuing lots of requests is not usually a
		910	problem.
		911
		912	Each thread needs a stack area which is usually around 16k, sometimes much
		913	larger, depending on the OS.
		914
764	=head1 SEE ALSO	915	=head1 SEE ALSO
765		916
766	L<Coro>, L<Linux::AIO> (obsolete).	917	L<Coro::AIO>.
767		918
768	=head1 AUTHOR	919	=head1 AUTHOR
769		920
770	Marc Lehmann <schmorp@schmorp.de>	921	Marc Lehmann <schmorp@schmorp.de>
771	http://home.schmorp.de/	922	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.55 by root, Sun Oct 22 00:49:29 2006 UTC vs. Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.55 by root, Sun Oct 22 00:49:29 2006 UTC vs.
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC