[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 1.68 by root, Tue Oct 24 03:17:39 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));
		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);
…		…
117	your pathnames to the locale (or other) encoding in effect in the user	123	your pathnames to the locale (or other) encoding in effect in the user
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
		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.
122		137
123	=item aio_open $pathname, $flags, $mode, $callback->($fh)	138	=item aio_open $pathname, $flags, $mode, $callback->($fh)
124		139
125	Asynchronously open or create a file and call the callback with a newly	140	Asynchronously open or create a file and call the callback with a newly
126	created filehandle for the file.	141	created filehandle for the file.
…		…
179	print "read $_[0] bytes: <$buffer>\n";	194	print "read $_[0] bytes: <$buffer>\n";
180	};	195	};
181		196
182	=item aio_move $srcpath, $dstpath, $callback->($status)	197	=item aio_move $srcpath, $dstpath, $callback->($status)
183		198
		199	[EXPERIMENTAL due to internal aio_group use]
		200
184	Try to move the I<file> (directories not supported as either source or	201	Try to move the I<file> (directories not supported as either source or
185	destination) from C<$srcpath> to C<$dstpath> and call the callback with	202	destination) from C<$srcpath> to C<$dstpath> and call the callback with
186	the C<0> (error) or C<-1> ok.	203	the C<0> (error) or C<-1> ok.
187		204
188	This is a composite request that tries to rename(2) the file first. If	205	This is a composite request that tries to rename(2) the file first. If
…		…
198	=cut	215	=cut
199		216
200	sub aio_move($$$) {	217	sub aio_move($$$) {
201	my ($src, $dst, $cb) = @_;	218	my ($src, $dst, $cb) = @_;
202		219
203	my $grp = aio_group;	220	my $grp = aio_group $cb;
204		221
205	add $grp aio_rename $src, $dst, sub {	222	add $grp aio_rename $src, $dst, sub {
206	if ($_[0] && $! == EXDEV) {	223	if ($_[0] && $! == EXDEV) {
207	add $grp aio_open $src, O_RDONLY, 0, sub {	224	add $grp aio_open $src, O_RDONLY, 0, sub {
208	if (my $src_fh = $_[0]) {	225	if (my $src_fh = $_[0]) {
…		…
218	chmod $stat[2] & 07777, $dst_fh;	235	chmod $stat[2] & 07777, $dst_fh;
219	chown $stat[4], $stat[5], $dst_fh;	236	chown $stat[4], $stat[5], $dst_fh;
220	close $dst_fh;	237	close $dst_fh;
221		238
222	add $grp aio_unlink $src, sub {	239	add $grp aio_unlink $src, sub {
223	$cb->($_[0]);	240	$grp->result ($_[0]);
224	};	241	};
225	} else {	242	} else {
226	my $errno = $!;	243	my $errno = $!;
227	add $grp aio_unlink $dst, sub {	244	add $grp aio_unlink $dst, sub {
228	$! = $errno;	245	$! = $errno;
229	$cb->(-1);	246	$grp->result (-1);
230	};	247	};
231	}	248	}
232	};	249	};
233	} else {	250	} else {
234	$cb->(-1);	251	$grp->result (-1);
235	}	252	}
236	},	253	},
237		254
238	} else {	255	} else {
239	$cb->(-1);	256	$grp->result (-1);
240	}	257	}
241	};	258	};
242	} else {	259	} else {
243	$cb->($_[0]);	260	$grp->result ($_[0]);
244	}	261	}
245	};	262	};
246		263
247	$grp	264	$grp
248	}	265	}
…		…
340	The callback a single argument which is either C<undef> or an array-ref	357	The callback a single argument which is either C<undef> or an array-ref
341	with the filenames.	358	with the filenames.
342		359
343	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	360	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
344		361
		362	[EXPERIMENTAL due to internal aio_group use]
		363
345	Scans a directory (similar to C<aio_readdir>) but additionally tries to	364	Scans a directory (similar to C<aio_readdir>) but additionally tries to
346	separate the entries of directory C<$path> into two sets of names, ones	365	separate the entries of directory C<$path> into two sets of names, ones
347	you can recurse into (directories or links to them), and ones you cannot	366	you can recurse into (directories or links to them), and ones you cannot
348	recurse into (everything else).	367	recurse into (everything else).
349		368
350	C<aio_scandir> is a composite request that consists of many sub	369	C<aio_scandir> is a composite request that creates of many sub requests_
351	requests. C<$maxreq> specifies the maximum number of outstanding aio	370	C<$maxreq> specifies the maximum number of outstanding aio requests that
352	requests that this function generates. If it is C<< <= 0 >>, then a	371	this function generates. If it is C<< <= 0 >>, then a suitable default
353	suitable default will be chosen (currently 8).	372	will be chosen (currently 6).
354		373
355	On error, the callback is called without arguments, otherwise it receives	374	On error, the callback is called without arguments, otherwise it receives
356	two array-refs with path-relative entry names.	375	two array-refs with path-relative entry names.
357		376
358	Example:	377	Example:
…		…
395	=cut	414	=cut
396		415
397	sub aio_scandir($$$) {	416	sub aio_scandir($$$) {
398	my ($path, $maxreq, $cb) = @_;	417	my ($path, $maxreq, $cb) = @_;
399		418
400	my $grp = aio_group;	419	my $grp = aio_group $cb;
401		420
402	$maxreq = 8 if $maxreq <= 0;	421	$maxreq = 6 if $maxreq <= 0;
403		422
404	# stat once	423	# stat once
405	add $grp aio_stat $path, sub {	424	add $grp aio_stat $path, sub {
406	return $cb->() if $_[0];	425	return $grp->result () if $_[0];
407	my $now = time;	426	my $now = time;
408	my $hash1 = join ":", (stat _)[0,1,3,7,9];	427	my $hash1 = join ":", (stat _)[0,1,3,7,9];
409		428
410	# read the directory entries	429	# read the directory entries
411	add $grp aio_readdir $path, sub {	430	add $grp aio_readdir $path, sub {
412	my $entries = shift	431	my $entries = shift
413	or return $cb->();	432	or return $grp->result ();
414		433
415	# stat the dir another time	434	# stat the dir another time
416	add $grp aio_stat $path, sub {	435	add $grp aio_stat $path, sub {
417	my $hash2 = join ":", (stat _)[0,1,3,7,9];	436	my $hash2 = join ":", (stat _)[0,1,3,7,9];
418		437
…		…
423	$ndirs = -1;	442	$ndirs = -1;
424	} else {	443	} else {
425	# if nlink == 2, we are finished	444	# if nlink == 2, we are finished
426	# on non-posix-fs's, we rely on nlink < 2	445	# on non-posix-fs's, we rely on nlink < 2
427	$ndirs = (stat _)[3] - 2	446	$ndirs = (stat _)[3] - 2
428	or return $cb->([], $entries);	447	or return $grp->result ([], $entries);
429	}	448	}
430		449
431	# sort into likely dirs and likely nondirs	450	# sort into likely dirs and likely nondirs
432	# dirs == files without ".", short entries first	451	# dirs == files without ".", short entries first
433	$entries = [map $_->[0],	452	$entries = [map $_->[0],
…		…
438	my (@dirs, @nondirs);	457	my (@dirs, @nondirs);
439		458
440	my ($statcb, $schedcb);	459	my ($statcb, $schedcb);
441	my $nreq = 0;	460	my $nreq = 0;
442		461
		462	my $statgrp = add $grp aio_group;
		463
443	$schedcb = sub {	464	$schedcb = sub {
444	if (@$entries) {	465	if (@$entries) {
445	if ($nreq < $maxreq) {	466	if ($nreq < $maxreq) {
446	my $ent = pop @$entries;	467	my $ent = pop @$entries;
447	$nreq++;	468	$nreq++;
448	add $grp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };	469	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
449	}	470	}
450	} elsif (!$nreq) {	471	} elsif (!$nreq) {
451	# finished	472	# finished
		473	$statgrp->cancel;
452	undef $statcb;	474	undef $statcb;
453	undef $schedcb;	475	undef $schedcb;
454	$cb->(\@dirs, \@nondirs) if $cb;	476	$grp->result (\@dirs, \@nondirs);
455	undef $cb;
456	}	477	}
457	};	478	};
458	$statcb = sub {	479	$statcb = sub {
459	my ($status, $entry) = @_;	480	my ($status, $entry) = @_;
460		481
…		…
502	callback with the fdatasync result code.	523	callback with the fdatasync result code.
503		524
504	If this call isn't available because your OS lacks it or it couldn't be	525	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.	526	detected, it will be emulated by calling C<fsync> instead.
506		527
507	=item aio_group $callback->()	528	=item aio_group $callback->(...)
508		529
509	[EXPERIMENTAL]	530	[EXPERIMENTAL]
510		531
511	This is a very special aio request: Instead of doing something, it is a	532	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	533	container for other aio requests, which is useful if you want to bundle
…		…
524	add $grp	545	add $grp
525	(aio_stat ...),	546	(aio_stat ...),
526	(aio_stat ...),	547	(aio_stat ...),
527	...;	548	...;
528		549
		550	=item aio_nop $callback->()
		551
		552	This is a special request - it does nothing in itself and is only used for
		553	side effects, such as when you want to add a dummy request to a group so
		554	that finishing the requests in the group depends on executing the given
		555	code.
		556
		557	While this request does nothing, it still goes through the execution
		558	phase and still requires a worker thread. Thus, the callback will not
		559	be executed immediately but only after other requests in the queue have
		560	entered their execution phase. This can be used to measure request
		561	latency.
		562
529	=item aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	563	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED
530		564
531	Mainly used for debugging and benchmarking, this aio request puts one of	565	Mainly used for debugging and benchmarking, this aio request puts one of
532	the request workers to sleep for the given time.	566	the request workers to sleep for the given time.
		567
		568	While it is theoretically handy to have simple I/O scheduling requests
		569	like sleep and file handle readable/writable, the overhead this creates
		570	is immense, so do not use this function except to put your application
		571	under artificial I/O pressure.
533		572
534	=back	573	=back
535		574
536	=head2 IO::AIO::REQ CLASS	575	=head2 IO::AIO::REQ CLASS
537		576
…		…
546	callback) and B<done> (request has reached the end of its lifetime and	585	callback) and B<done> (request has reached the end of its lifetime and
547	holds no resources anymore).	586	holds no resources anymore).
548		587
549	=over 4	588	=over 4
550		589
551	=item $req->cancel	590	=item cancel $req
552		591
553	Cancels the request, if possible. Has the effect of skipping execution	592	Cancels the request, if possible. Has the effect of skipping execution
554	when entering the B<execute> state and skipping calling the callback when	593	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	594	entering the the B<result> state, but will leave the request otherwise
556	untouched. That means that requests that currently execute will not be	595	untouched. That means that requests that currently execute will not be
557	stopped and resources held by the request will not be freed prematurely.	596	stopped and resources held by the request will not be freed prematurely.
558		597
		598	=item cb $req $callback->(...)
		599
		600	Replace (or simply set) the callback registered to the request.
		601
559	=back	602	=back
560		603
561	=head2 IO::AIO::GRP CLASS	604	=head2 IO::AIO::GRP CLASS
562		605
563	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to	606	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	620	You add requests by calling the C<add> method with one or more
578	C<IO::AIO::REQ> objects:	621	C<IO::AIO::REQ> objects:
579		622
580	$grp->add (aio_unlink "...");	623	$grp->add (aio_unlink "...");
581		624
582	add $grp aio_stat "...", sub { ... };	625	add $grp aio_stat "...", sub {
		626	$_[0] or return $grp->result ("error");
		627
		628	# add another request dynamically, if first succeeded
		629	add $grp aio_open "...", sub {
		630	$grp->result ("ok");
		631	};
		632	};
583		633
584	This makes it very easy to create composite requests (see the source of	634	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.	635	C<aio_move> for an application) that work and feel like simple requests.
586		636
		637	=over 4
		638
587	The IO::AIO::GRP objects will be cleaned up during calls to	639	=item * The IO::AIO::GRP objects will be cleaned up during calls to
588	C<IO::AIO::poll_cb>, just like any other request.	640	C<IO::AIO::poll_cb>, just like any other request.
589		641
590	They can be canceled like any other request. Canceling will cancel not	642	=item * They can be canceled like any other request. Canceling will cancel not
591	just the request itself, but also all requests it contains.	643	only the request itself, but also all requests it contains.
592		644
593	They can also can also be added to other IO::AIO::GRP objects.	645	=item * They can also can also be added to other IO::AIO::GRP objects.
		646
		647	=item * You must not add requests to a group from within the group callback (or
		648	any later time).
		649
		650	=item * This does not harmonise well with C<max_outstanding>, so best do
		651	not combine C<aio_group> with it. Groups and feeders are recommended for
		652	this kind of concurrency-limiting.
		653
		654	=back
594		655
595	Their lifetime, simplified, looks like this: when they are empty, they	656	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	657	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	658	C<done> state, they will also finish. Otherwise they will continue to
598	exist.	659	exist.
599		660
		661	That means after creating a group you have some time to add requests. And
		662	in the callbacks of those requests, you can add further requests to the
		663	group. And only when all those requests have finished will the the group
		664	itself finish.
		665
600	=over 4	666	=over 4
601		667
		668	=item add $grp ...
		669
602	=item $grp->add (...)	670	=item $grp->add (...)
603		671
604	=item add $grp ...	672	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
		673	be added, including other groups, as long as you do not create circular
		674	dependencies.
605		675
606	Add one or more	676	Returns all its arguments.
607	Cancels the request, if possible. Has the effect of skipping execution	677
608	when entering the B<execute> state and skipping calling the callback when	678	=item $grp->result (...)
609	entering the the B<result> state, but will leave the request otherwise	679
610	untouched. That means that requests that currently execute will not be	680	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.	681	subrequests have finished. By default, no argument will be passed.
		682
		683	=item feed $grp $callback->($grp)
		684
		685	[VERY EXPERIMENTAL]
		686
		687	Sets a feeder/generator on this group: every group can have an attached
		688	generator that generates requests if idle. The idea behind this is that,
		689	although you could just queue as many requests as you want in a group,
		690	this might starve other requests for a potentially long time. For
		691	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
		692	requests, delaying any later requests for a long time.
		693
		694	To avoid this, and allow incremental generation of requests, you can
		695	instead a group and set a feeder on it that generates those requests. The
		696	feed callback will be called whenever there are few enough (see C<limit>,
		697	below) requests active in the group itself and is expected to queue more
		698	requests.
		699
		700	The feed callback can queue as many requests as it likes (i.e. C<add> does
		701	not impose any limits).
		702
		703	If the feed does not queue more requests when called, it will be
		704	automatically removed from the group.
		705
		706	If the feed limit is C<0>, it will be set to C<2> automatically.
		707
		708	Example:
		709
		710	# stat all files in @files, but only ever use four aio requests concurrently:
		711
		712	my $grp = aio_group sub { print "finished\n" };
		713	limit $grp 4;
		714	feed $grp sub {
		715	my $file = pop @files
		716	or return;
		717
		718	add $grp aio_stat $file, sub { ... };
		719	};
		720
		721	=item limit $grp $num
		722
		723	Sets the feeder limit for the group: The feeder will be called whenever
		724	the group contains less than this many requests.
		725
		726	Setting the limit to C<0> will pause the feeding process.
612		727
613	=back	728	=back
614		729
615	=head2 SUPPORT FUNCTIONS	730	=head2 SUPPORT FUNCTIONS
616		731
…		…
674	IO::AIO::poll_wait, IO::AIO::poll_cb	789	IO::AIO::poll_wait, IO::AIO::poll_cb
675	if IO::AIO::nreqs;	790	if IO::AIO::nreqs;
676		791
677	=item IO::AIO::min_parallel $nthreads	792	=item IO::AIO::min_parallel $nthreads
678		793
679	Set the minimum number of AIO threads to C<$nthreads>. The current default	794	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	795	default is C<8>, which means eight asynchronous operations can execute
681	(the number of outstanding operations, however, is unlimited).	796	concurrently at any one time (the number of outstanding requests,
		797	however, is unlimited).
682		798
683	IO::AIO starts threads only on demand, when an AIO request is queued and	799	IO::AIO starts threads only on demand, when an AIO request is queued and
684	no free thread exists.	800	no free thread exists.
685		801
686	It is recommended to keep the number of threads low, as some Linux	802	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	803	Linux kernel versions will scale negatively with the number of threads
688	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	804	(higher parallelity => MUCH higher latency). With current Linux 2.6
689	threads should be fine.	805	versions, 4-32 threads should be fine.
690		806
691	Under most circumstances you don't need to call this function, as the	807	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.	808	module selects a default that is suitable for low to moderate load.
693		809
694	=item IO::AIO::max_parallel $nthreads	810	=item IO::AIO::max_parallel $nthreads
…		…
705		821
706	Under normal circumstances you don't need to call this function.	822	Under normal circumstances you don't need to call this function.
707		823
708	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	824	=item $oldnreqs = IO::AIO::max_outstanding $nreqs
709		825
		826	[DEPRECATED]
		827
710	Sets the maximum number of outstanding requests to C<$nreqs>. If you	828	Sets the maximum number of outstanding requests to C<$nreqs>. If you
711	try to queue up more than this number of requests, the caller will block until	829	try to queue up more than this number of requests, the caller will block until
712	some requests have been handled.	830	some requests have been handled.
713		831
714	The default is very large, so normally there is no practical limit. If you	832	The default is very large, so normally there is no practical limit. If you
715	queue up many requests in a loop it often improves speed if you set	833	queue up many requests in a loop it often improves speed if you set
716	this to a relatively low number, such as C<100>.	834	this to a relatively low number, such as C<100>.
		835
		836	This function does not work well together with C<aio_group>'s, and their
		837	feeder interface is better suited to limiting concurrency, so do not use
		838	this function.
717		839
718	Under normal circumstances you don't need to call this function.	840	Under normal circumstances you don't need to call this function.
719		841
720	=back	842	=back
721		843
…		…
735	or return undef;	857	or return undef;
736		858
737	*$sym	859	*$sym
738	}	860	}
739		861
740	min_parallel 4;	862	min_parallel 8;
741		863
742	END {	864	END {
743	max_parallel 0;	865	max_parallel 0;
744	}	866	}
745		867
…		…
759		881
760	In short: the parent will, after a short pause, continue as if fork had	882	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	883	not been called, while the child will act as if IO::AIO has not been used
762	yet.	884	yet.
763		885
		886	=head2 MEMORY USAGE
		887
		888	Each aio request uses - depending on your architecture - around 128 bytes
		889	of memory. In addition, stat requests need a stat buffer (possibly a few
		890	hundred bytes). Perl scalars and other data passed into aio requests will
		891	also be locked.
		892
		893	This is now awfully much, so queuing lots of requests is not usually a
		894	problem.
		895
		896	Each thread needs a stack area which is usually around 16k, sometimes much
		897	larger, depending on the OS.
		898
764	=head1 SEE ALSO	899	=head1 SEE ALSO
765		900
766	L<Coro>, L<Linux::AIO> (obsolete).	901	L<Coro::AIO>.
767		902
768	=head1 AUTHOR	903	=head1 AUTHOR
769		904
770	Marc Lehmann <schmorp@schmorp.de>	905	Marc Lehmann <schmorp@schmorp.de>
771	http://home.schmorp.de/	906	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 1.68 by root, Tue Oct 24 03:17:39 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 1.68 by root, Tue Oct 24 03:17:39 2006 UTC