[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 1.69 by root, Tue Oct 24 03:40:25 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);
…		…
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
…		…
179	print "read $_[0] bytes: <$buffer>\n";	213	print "read $_[0] bytes: <$buffer>\n";
180	};	214	};
181		215
182	=item aio_move $srcpath, $dstpath, $callback->($status)	216	=item aio_move $srcpath, $dstpath, $callback->($status)
183		217
		218	[EXPERIMENTAL due to internal aio_group use]
		219
184	Try to move the I<file> (directories not supported as either source or	220	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	221	destination) from C<$srcpath> to C<$dstpath> and call the callback with
186	the C<0> (error) or C<-1> ok.	222	the C<0> (error) or C<-1> ok.
187		223
188	This is a composite request that tries to rename(2) the file first. If	224	This is a composite request that tries to rename(2) the file first. If
…		…
198	=cut	234	=cut
199		235
200	sub aio_move($$$) {	236	sub aio_move($$$) {
201	my ($src, $dst, $cb) = @_;	237	my ($src, $dst, $cb) = @_;
202		238
203	my $grp = aio_group;	239	my $grp = aio_group $cb;
204		240
205	add $grp aio_rename $src, $dst, sub {	241	add $grp aio_rename $src, $dst, sub {
206	if ($_[0] && $! == EXDEV) {	242	if ($_[0] && $! == EXDEV) {
207	add $grp aio_open $src, O_RDONLY, 0, sub {	243	add $grp aio_open $src, O_RDONLY, 0, sub {
208	if (my $src_fh = $_[0]) {	244	if (my $src_fh = $_[0]) {
…		…
218	chmod $stat[2] & 07777, $dst_fh;	254	chmod $stat[2] & 07777, $dst_fh;
219	chown $stat[4], $stat[5], $dst_fh;	255	chown $stat[4], $stat[5], $dst_fh;
220	close $dst_fh;	256	close $dst_fh;
221		257
222	add $grp aio_unlink $src, sub {	258	add $grp aio_unlink $src, sub {
223	$cb->($_[0]);	259	$grp->result ($_[0]);
224	};	260	};
225	} else {	261	} else {
226	my $errno = $!;	262	my $errno = $!;
227	add $grp aio_unlink $dst, sub {	263	add $grp aio_unlink $dst, sub {
228	$! = $errno;	264	$! = $errno;
229	$cb->(-1);	265	$grp->result (-1);
230	};	266	};
231	}	267	}
232	};	268	};
233	} else {	269	} else {
234	$cb->(-1);	270	$grp->result (-1);
235	}	271	}
236	},	272	},
237		273
238	} else {	274	} else {
239	$cb->(-1);	275	$grp->result (-1);
240	}	276	}
241	};	277	};
242	} else {	278	} else {
243	$cb->($_[0]);	279	$grp->result ($_[0]);
244	}	280	}
245	};	281	};
246		282
247	$grp	283	$grp
248	}	284	}
…		…
340	The callback a single argument which is either C<undef> or an array-ref	376	The callback a single argument which is either C<undef> or an array-ref
341	with the filenames.	377	with the filenames.
342		378
343	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	379	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
344		380
		381	[EXPERIMENTAL due to internal aio_group use]
		382
345	Scans a directory (similar to C<aio_readdir>) but additionally tries to	383	Scans a directory (similar to C<aio_readdir>) but additionally tries to
346	separate the entries of directory C<$path> into two sets of names, ones	384	separate the entries of directory C<$path> into two sets of names, ones
347	you can recurse into (directories or links to them), and ones you cannot	385	you can recurse into (directories or links to them), and ones you cannot
348	recurse into (everything else).	386	recurse into (everything else).
349		387
350	C<aio_scandir> is a composite request that consists of many sub	388	C<aio_scandir> is a composite request that creates of many sub requests_
351	requests. C<$maxreq> specifies the maximum number of outstanding aio	389	C<$maxreq> specifies the maximum number of outstanding aio requests that
352	requests that this function generates. If it is C<< <= 0 >>, then a	390	this function generates. If it is C<< <= 0 >>, then a suitable default
353	suitable default will be chosen (currently 8).	391	will be chosen (currently 6).
354		392
355	On error, the callback is called without arguments, otherwise it receives	393	On error, the callback is called without arguments, otherwise it receives
356	two array-refs with path-relative entry names.	394	two array-refs with path-relative entry names.
357		395
358	Example:	396	Example:
…		…
395	=cut	433	=cut
396		434
397	sub aio_scandir($$$) {	435	sub aio_scandir($$$) {
398	my ($path, $maxreq, $cb) = @_;	436	my ($path, $maxreq, $cb) = @_;
399		437
400	my $grp = aio_group;	438	my $grp = aio_group $cb;
401		439
402	$maxreq = 8 if $maxreq <= 0;	440	$maxreq = 6 if $maxreq <= 0;
403		441
404	# stat once	442	# stat once
405	add $grp aio_stat $path, sub {	443	add $grp aio_stat $path, sub {
406	return $cb->() if $_[0];	444	return $grp->result () if $_[0];
407	my $now = time;	445	my $now = time;
408	my $hash1 = join ":", (stat _)[0,1,3,7,9];	446	my $hash1 = join ":", (stat _)[0,1,3,7,9];
409		447
410	# read the directory entries	448	# read the directory entries
411	add $grp aio_readdir $path, sub {	449	add $grp aio_readdir $path, sub {
412	my $entries = shift	450	my $entries = shift
413	or return $cb->();	451	or return $grp->result ();
414		452
415	# stat the dir another time	453	# stat the dir another time
416	add $grp aio_stat $path, sub {	454	add $grp aio_stat $path, sub {
417	my $hash2 = join ":", (stat _)[0,1,3,7,9];	455	my $hash2 = join ":", (stat _)[0,1,3,7,9];
418		456
…		…
423	$ndirs = -1;	461	$ndirs = -1;
424	} else {	462	} else {
425	# if nlink == 2, we are finished	463	# if nlink == 2, we are finished
426	# on non-posix-fs's, we rely on nlink < 2	464	# on non-posix-fs's, we rely on nlink < 2
427	$ndirs = (stat _)[3] - 2	465	$ndirs = (stat _)[3] - 2
428	or return $cb->([], $entries);	466	or return $grp->result ([], $entries);
429	}	467	}
430		468
431	# sort into likely dirs and likely nondirs	469	# sort into likely dirs and likely nondirs
432	# dirs == files without ".", short entries first	470	# dirs == files without ".", short entries first
433	$entries = [map $_->[0],	471	$entries = [map $_->[0],
…		…
438	my (@dirs, @nondirs);	476	my (@dirs, @nondirs);
439		477
440	my ($statcb, $schedcb);	478	my ($statcb, $schedcb);
441	my $nreq = 0;	479	my $nreq = 0;
442		480
		481	my $statgrp = add $grp aio_group;
		482
443	$schedcb = sub {	483	$schedcb = sub {
444	if (@$entries) {	484	if (@$entries) {
445	if ($nreq < $maxreq) {	485	if ($nreq < $maxreq) {
446	my $ent = pop @$entries;	486	my $ent = pop @$entries;
447	$nreq++;	487	$nreq++;
448	add $grp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };	488	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
449	}	489	}
450	} elsif (!$nreq) {	490	} elsif (!$nreq) {
451	# finished	491	# finished
		492	$statgrp->cancel;
452	undef $statcb;	493	undef $statcb;
453	undef $schedcb;	494	undef $schedcb;
454	$cb->(\@dirs, \@nondirs) if $cb;	495	$grp->result (\@dirs, \@nondirs);
455	undef $cb;
456	}	496	}
457	};	497	};
458	$statcb = sub {	498	$statcb = sub {
459	my ($status, $entry) = @_;	499	my ($status, $entry) = @_;
460		500
…		…
502	callback with the fdatasync result code.	542	callback with the fdatasync result code.
503		543
504	If this call isn't available because your OS lacks it or it couldn't be	544	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.	545	detected, it will be emulated by calling C<fsync> instead.
506		546
507	=item aio_group $callback->()	547	=item aio_group $callback->(...)
508		548
509	[EXPERIMENTAL]	549	[EXPERIMENTAL]
510		550
511	This is a very special aio request: Instead of doing something, it is a	551	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	552	container for other aio requests, which is useful if you want to bundle
…		…
524	add $grp	564	add $grp
525	(aio_stat ...),	565	(aio_stat ...),
526	(aio_stat ...),	566	(aio_stat ...),
527	...;	567	...;
528		568
		569	=item aio_nop $callback->()
		570
		571	This is a special request - it does nothing in itself and is only used for
		572	side effects, such as when you want to add a dummy request to a group so
		573	that finishing the requests in the group depends on executing the given
		574	code.
		575
		576	While this request does nothing, it still goes through the execution
		577	phase and still requires a worker thread. Thus, the callback will not
		578	be executed immediately but only after other requests in the queue have
		579	entered their execution phase. This can be used to measure request
		580	latency.
		581
529	=item aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	582	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED
530		583
531	Mainly used for debugging and benchmarking, this aio request puts one of	584	Mainly used for debugging and benchmarking, this aio request puts one of
532	the request workers to sleep for the given time.	585	the request workers to sleep for the given time.
		586
		587	While it is theoretically handy to have simple I/O scheduling requests
		588	like sleep and file handle readable/writable, the overhead this creates
		589	is immense, so do not use this function except to put your application
		590	under artificial I/O pressure.
533		591
534	=back	592	=back
535		593
536	=head2 IO::AIO::REQ CLASS	594	=head2 IO::AIO::REQ CLASS
537		595
…		…
546	callback) and B<done> (request has reached the end of its lifetime and	604	callback) and B<done> (request has reached the end of its lifetime and
547	holds no resources anymore).	605	holds no resources anymore).
548		606
549	=over 4	607	=over 4
550		608
551	=item $req->cancel	609	=item cancel $req
552		610
553	Cancels the request, if possible. Has the effect of skipping execution	611	Cancels the request, if possible. Has the effect of skipping execution
554	when entering the B<execute> state and skipping calling the callback when	612	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	613	entering the the B<result> state, but will leave the request otherwise
556	untouched. That means that requests that currently execute will not be	614	untouched. That means that requests that currently execute will not be
557	stopped and resources held by the request will not be freed prematurely.	615	stopped and resources held by the request will not be freed prematurely.
558		616
		617	=item cb $req $callback->(...)
		618
		619	Replace (or simply set) the callback registered to the request.
		620
559	=back	621	=back
560		622
561	=head2 IO::AIO::GRP CLASS	623	=head2 IO::AIO::GRP CLASS
562		624
563	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to	625	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	639	You add requests by calling the C<add> method with one or more
578	C<IO::AIO::REQ> objects:	640	C<IO::AIO::REQ> objects:
579		641
580	$grp->add (aio_unlink "...");	642	$grp->add (aio_unlink "...");
581		643
582	add $grp aio_stat "...", sub { ... };	644	add $grp aio_stat "...", sub {
		645	$_[0] or return $grp->result ("error");
		646
		647	# add another request dynamically, if first succeeded
		648	add $grp aio_open "...", sub {
		649	$grp->result ("ok");
		650	};
		651	};
583		652
584	This makes it very easy to create composite requests (see the source of	653	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.	654	C<aio_move> for an application) that work and feel like simple requests.
586		655
		656	=over 4
		657
587	The IO::AIO::GRP objects will be cleaned up during calls to	658	=item * The IO::AIO::GRP objects will be cleaned up during calls to
588	C<IO::AIO::poll_cb>, just like any other request.	659	C<IO::AIO::poll_cb>, just like any other request.
589		660
590	They can be canceled like any other request. Canceling will cancel not	661	=item * They can be canceled like any other request. Canceling will cancel not
591	just the request itself, but also all requests it contains.	662	only the request itself, but also all requests it contains.
592		663
593	They can also can also be added to other IO::AIO::GRP objects.	664	=item * They can also can also be added to other IO::AIO::GRP objects.
		665
		666	=item * You must not add requests to a group from within the group callback (or
		667	any later time).
		668
		669	=item * This does not harmonise well with C<max_outstanding>, so best do
		670	not combine C<aio_group> with it. Groups and feeders are recommended for
		671	this kind of concurrency-limiting.
		672
		673	=back
594		674
595	Their lifetime, simplified, looks like this: when they are empty, they	675	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	676	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	677	C<done> state, they will also finish. Otherwise they will continue to
598	exist.	678	exist.
599		679
		680	That means after creating a group you have some time to add requests. And
		681	in the callbacks of those requests, you can add further requests to the
		682	group. And only when all those requests have finished will the the group
		683	itself finish.
		684
600	=over 4	685	=over 4
601		686
		687	=item add $grp ...
		688
602	=item $grp->add (...)	689	=item $grp->add (...)
603		690
604	=item add $grp ...	691	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
		692	be added, including other groups, as long as you do not create circular
		693	dependencies.
605		694
606	Add one or more	695	Returns all its arguments.
607	Cancels the request, if possible. Has the effect of skipping execution	696
608	when entering the B<execute> state and skipping calling the callback when	697	=item $grp->result (...)
609	entering the the B<result> state, but will leave the request otherwise	698
610	untouched. That means that requests that currently execute will not be	699	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.	700	subrequests have finished. By default, no argument will be passed.
		701
		702	=item feed $grp $callback->($grp)
		703
		704	[VERY EXPERIMENTAL]
		705
		706	Sets a feeder/generator on this group: every group can have an attached
		707	generator that generates requests if idle. The idea behind this is that,
		708	although you could just queue as many requests as you want in a group,
		709	this might starve other requests for a potentially long time. For
		710	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
		711	requests, delaying any later requests for a long time.
		712
		713	To avoid this, and allow incremental generation of requests, you can
		714	instead a group and set a feeder on it that generates those requests. The
		715	feed callback will be called whenever there are few enough (see C<limit>,
		716	below) requests active in the group itself and is expected to queue more
		717	requests.
		718
		719	The feed callback can queue as many requests as it likes (i.e. C<add> does
		720	not impose any limits).
		721
		722	If the feed does not queue more requests when called, it will be
		723	automatically removed from the group.
		724
		725	If the feed limit is C<0>, it will be set to C<2> automatically.
		726
		727	Example:
		728
		729	# stat all files in @files, but only ever use four aio requests concurrently:
		730
		731	my $grp = aio_group sub { print "finished\n" };
		732	limit $grp 4;
		733	feed $grp sub {
		734	my $file = pop @files
		735	or return;
		736
		737	add $grp aio_stat $file, sub { ... };
		738	};
		739
		740	=item limit $grp $num
		741
		742	Sets the feeder limit for the group: The feeder will be called whenever
		743	the group contains less than this many requests.
		744
		745	Setting the limit to C<0> will pause the feeding process.
612		746
613	=back	747	=back
614		748
615	=head2 SUPPORT FUNCTIONS	749	=head2 SUPPORT FUNCTIONS
616		750
…		…
674	IO::AIO::poll_wait, IO::AIO::poll_cb	808	IO::AIO::poll_wait, IO::AIO::poll_cb
675	if IO::AIO::nreqs;	809	if IO::AIO::nreqs;
676		810
677	=item IO::AIO::min_parallel $nthreads	811	=item IO::AIO::min_parallel $nthreads
678		812
679	Set the minimum number of AIO threads to C<$nthreads>. The current default	813	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	814	default is C<8>, which means eight asynchronous operations can execute
681	(the number of outstanding operations, however, is unlimited).	815	concurrently at any one time (the number of outstanding requests,
		816	however, is unlimited).
682		817
683	IO::AIO starts threads only on demand, when an AIO request is queued and	818	IO::AIO starts threads only on demand, when an AIO request is queued and
684	no free thread exists.	819	no free thread exists.
685		820
686	It is recommended to keep the number of threads low, as some Linux	821	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	822	Linux kernel versions will scale negatively with the number of threads
688	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	823	(higher parallelity => MUCH higher latency). With current Linux 2.6
689	threads should be fine.	824	versions, 4-32 threads should be fine.
690		825
691	Under most circumstances you don't need to call this function, as the	826	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.	827	module selects a default that is suitable for low to moderate load.
693		828
694	=item IO::AIO::max_parallel $nthreads	829	=item IO::AIO::max_parallel $nthreads
…		…
705		840
706	Under normal circumstances you don't need to call this function.	841	Under normal circumstances you don't need to call this function.
707		842
708	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	843	=item $oldnreqs = IO::AIO::max_outstanding $nreqs
709		844
		845	[DEPRECATED]
		846
710	Sets the maximum number of outstanding requests to C<$nreqs>. If you	847	Sets the maximum number of outstanding requests to C<$nreqs>. If you
711	try to queue up more than this number of requests, the caller will block until	848	try to queue up more than this number of requests, the caller will block until
712	some requests have been handled.	849	some requests have been handled.
713		850
714	The default is very large, so normally there is no practical limit. If you	851	The default is very large, so normally there is no practical limit. If you
715	queue up many requests in a loop it often improves speed if you set	852	queue up many requests in a loop it often improves speed if you set
716	this to a relatively low number, such as C<100>.	853	this to a relatively low number, such as C<100>.
		854
		855	This function does not work well together with C<aio_group>'s, and their
		856	feeder interface is better suited to limiting concurrency, so do not use
		857	this function.
717		858
718	Under normal circumstances you don't need to call this function.	859	Under normal circumstances you don't need to call this function.
719		860
720	=back	861	=back
721		862
…		…
735	or return undef;	876	or return undef;
736		877
737	*$sym	878	*$sym
738	}	879	}
739		880
740	min_parallel 4;	881	min_parallel 8;
741		882
742	END {	883	END {
743	max_parallel 0;	884	max_parallel 0;
744	}	885	}
745		886
…		…
759		900
760	In short: the parent will, after a short pause, continue as if fork had	901	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	902	not been called, while the child will act as if IO::AIO has not been used
762	yet.	903	yet.
763		904
		905	=head2 MEMORY USAGE
		906
		907	Each aio request uses - depending on your architecture - around 128 bytes
		908	of memory. In addition, stat requests need a stat buffer (possibly a few
		909	hundred bytes). Perl scalars and other data passed into aio requests will
		910	also be locked.
		911
		912	This is now awfully much, so queuing lots of requests is not usually a
		913	problem.
		914
		915	Each thread needs a stack area which is usually around 16k, sometimes much
		916	larger, depending on the OS.
		917
764	=head1 SEE ALSO	918	=head1 SEE ALSO
765		919
766	L<Coro>, L<Linux::AIO> (obsolete).	920	L<Coro::AIO>.
767		921
768	=head1 AUTHOR	922	=head1 AUTHOR
769		923
770	Marc Lehmann <schmorp@schmorp.de>	924	Marc Lehmann <schmorp@schmorp.de>
771	http://home.schmorp.de/	925	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 1.69 by root, Tue Oct 24 03:40:25 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 1.69 by root, Tue Oct 24 03:40:25 2006 UTC