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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.56 by root, Sun Oct 22 00:53:47 2006 UTC vs.
Revision 1.64 by root, Mon Oct 23 00:50:10 2006 UTC

…		…
79	our $VERSION = '2.0';	79	our $VERSION = '2.0';
80		80
81	our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	81	our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
82	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	82	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
83	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	83	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
84	aio_group);	84	aio_group aio_nop);
85	our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	85	our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
86		86
87	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	87	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
88		88
89	require XSLoader;	89	require XSLoader;
…		…
182	print "read $_[0] bytes: <$buffer>\n";	182	print "read $_[0] bytes: <$buffer>\n";
183	};	183	};
184		184
185	=item aio_move $srcpath, $dstpath, $callback->($status)	185	=item aio_move $srcpath, $dstpath, $callback->($status)
186		186
		187	[EXPERIMENTAL due to internal aio_group use]
		188
187	Try to move the I<file> (directories not supported as either source or	189	Try to move the I<file> (directories not supported as either source or
188	destination) from C<$srcpath> to C<$dstpath> and call the callback with	190	destination) from C<$srcpath> to C<$dstpath> and call the callback with
189	the C<0> (error) or C<-1> ok.	191	the C<0> (error) or C<-1> ok.
190		192
191	This is a composite request that tries to rename(2) the file first. If	193	This is a composite request that tries to rename(2) the file first. If
…		…
201	=cut	203	=cut
202		204
203	sub aio_move($$$) {	205	sub aio_move($$$) {
204	my ($src, $dst, $cb) = @_;	206	my ($src, $dst, $cb) = @_;
205		207
206	my $grp = aio_group;	208	my $grp = aio_group $cb;
207		209
208	add $grp aio_rename $src, $dst, sub {	210	add $grp aio_rename $src, $dst, sub {
209	if ($_[0] && $! == EXDEV) {	211	if ($_[0] && $! == EXDEV) {
210	add $grp aio_open $src, O_RDONLY, 0, sub {	212	add $grp aio_open $src, O_RDONLY, 0, sub {
211	if (my $src_fh = $_[0]) {	213	if (my $src_fh = $_[0]) {
…		…
221	chmod $stat[2] & 07777, $dst_fh;	223	chmod $stat[2] & 07777, $dst_fh;
222	chown $stat[4], $stat[5], $dst_fh;	224	chown $stat[4], $stat[5], $dst_fh;
223	close $dst_fh;	225	close $dst_fh;
224		226
225	add $grp aio_unlink $src, sub {	227	add $grp aio_unlink $src, sub {
226	$cb->($_[0]);	228	$grp->result ($_[0]);
227	};	229	};
228	} else {	230	} else {
229	my $errno = $!;	231	my $errno = $!;
230	add $grp aio_unlink $dst, sub {	232	add $grp aio_unlink $dst, sub {
231	$! = $errno;	233	$! = $errno;
232	$cb->(-1);	234	$grp->result (-1);
233	};	235	};
234	}	236	}
235	};	237	};
236	} else {	238	} else {
237	$cb->(-1);	239	$grp->result (-1);
238	}	240	}
239	},	241	},
240		242
241	} else {	243	} else {
242	$cb->(-1);	244	$grp->result (-1);
243	}	245	}
244	};	246	};
245	} else {	247	} else {
246	$cb->($_[0]);	248	$grp->result ($_[0]);
247	}	249	}
248	};	250	};
249		251
250	$grp	252	$grp
251	}	253	}
…		…
343	The callback a single argument which is either C<undef> or an array-ref	345	The callback a single argument which is either C<undef> or an array-ref
344	with the filenames.	346	with the filenames.
345		347
346	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	348	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
347		349
		350	[EXPERIMENTAL due to internal aio_group use]
		351
348	Scans a directory (similar to C<aio_readdir>) but additionally tries to	352	Scans a directory (similar to C<aio_readdir>) but additionally tries to
349	separate the entries of directory C<$path> into two sets of names, ones	353	separate the entries of directory C<$path> into two sets of names, ones
350	you can recurse into (directories or links to them), and ones you cannot	354	you can recurse into (directories or links to them), and ones you cannot
351	recurse into (everything else).	355	recurse into (everything else).
352		356
353	C<aio_scandir> is a composite request that consists of many sub	357	C<aio_scandir> is a composite request that creates of many sub requests_
354	requests. C<$maxreq> specifies the maximum number of outstanding aio	358	C<$maxreq> specifies the maximum number of outstanding aio requests that
355	requests that this function generates. If it is C<< <= 0 >>, then a	359	this function generates. If it is C<< <= 0 >>, then a suitable default
356	suitable default will be chosen (currently 8).	360	will be chosen (currently 6).
357		361
358	On error, the callback is called without arguments, otherwise it receives	362	On error, the callback is called without arguments, otherwise it receives
359	two array-refs with path-relative entry names.	363	two array-refs with path-relative entry names.
360		364
361	Example:	365	Example:
…		…
398	=cut	402	=cut
399		403
400	sub aio_scandir($$$) {	404	sub aio_scandir($$$) {
401	my ($path, $maxreq, $cb) = @_;	405	my ($path, $maxreq, $cb) = @_;
402		406
403	my $grp = aio_group;	407	my $grp = aio_group $cb;
404		408
405	$maxreq = 8 if $maxreq <= 0;	409	$maxreq = 6 if $maxreq <= 0;
406		410
407	# stat once	411	# stat once
408	add $grp aio_stat $path, sub {	412	add $grp aio_stat $path, sub {
409	return $cb->() if $_[0];	413	return $grp->result () if $_[0];
410	my $now = time;	414	my $now = time;
411	my $hash1 = join ":", (stat _)[0,1,3,7,9];	415	my $hash1 = join ":", (stat _)[0,1,3,7,9];
412		416
413	# read the directory entries	417	# read the directory entries
414	add $grp aio_readdir $path, sub {	418	add $grp aio_readdir $path, sub {
415	my $entries = shift	419	my $entries = shift
416	or return $cb->();	420	or return $grp->result ();
417		421
418	# stat the dir another time	422	# stat the dir another time
419	add $grp aio_stat $path, sub {	423	add $grp aio_stat $path, sub {
420	my $hash2 = join ":", (stat _)[0,1,3,7,9];	424	my $hash2 = join ":", (stat _)[0,1,3,7,9];
421		425
…		…
426	$ndirs = -1;	430	$ndirs = -1;
427	} else {	431	} else {
428	# if nlink == 2, we are finished	432	# if nlink == 2, we are finished
429	# on non-posix-fs's, we rely on nlink < 2	433	# on non-posix-fs's, we rely on nlink < 2
430	$ndirs = (stat _)[3] - 2	434	$ndirs = (stat _)[3] - 2
431	or return $cb->([], $entries);	435	or return $grp->result ([], $entries);
432	}	436	}
433		437
434	# sort into likely dirs and likely nondirs	438	# sort into likely dirs and likely nondirs
435	# dirs == files without ".", short entries first	439	# dirs == files without ".", short entries first
436	$entries = [map $_->[0],	440	$entries = [map $_->[0],
…		…
441	my (@dirs, @nondirs);	445	my (@dirs, @nondirs);
442		446
443	my ($statcb, $schedcb);	447	my ($statcb, $schedcb);
444	my $nreq = 0;	448	my $nreq = 0;
445		449
		450	my $statgrp = add $grp aio_group;
		451
446	$schedcb = sub {	452	$schedcb = sub {
447	if (@$entries) {	453	if (@$entries) {
448	if ($nreq < $maxreq) {	454	if ($nreq < $maxreq) {
449	my $ent = pop @$entries;	455	my $ent = pop @$entries;
450	$nreq++;	456	$nreq++;
451	add $grp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };	457	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
452	}	458	}
453	} elsif (!$nreq) {	459	} elsif (!$nreq) {
454	# finished	460	# finished
		461	$statgrp->cancel;
455	undef $statcb;	462	undef $statcb;
456	undef $schedcb;	463	undef $schedcb;
457	$cb->(\@dirs, \@nondirs) if $cb;	464	$grp->result (\@dirs, \@nondirs);
458	undef $cb;
459	}	465	}
460	};	466	};
461	$statcb = sub {	467	$statcb = sub {
462	my ($status, $entry) = @_;	468	my ($status, $entry) = @_;
463		469
…		…
505	callback with the fdatasync result code.	511	callback with the fdatasync result code.
506		512
507	If this call isn't available because your OS lacks it or it couldn't be	513	If this call isn't available because your OS lacks it or it couldn't be
508	detected, it will be emulated by calling C<fsync> instead.	514	detected, it will be emulated by calling C<fsync> instead.
509		515
510	=item aio_group $callback->()	516	=item aio_group $callback->(...)
511		517
512	[EXPERIMENTAL]	518	[EXPERIMENTAL]
513		519
514	This is a very special aio request: Instead of doing something, it is a	520	This is a very special aio request: Instead of doing something, it is a
515	container for other aio requests, which is useful if you want to bundle	521	container for other aio requests, which is useful if you want to bundle
…		…
526		532
527	add $grp	533	add $grp
528	(aio_stat ...),	534	(aio_stat ...),
529	(aio_stat ...),	535	(aio_stat ...),
530	...;	536	...;
		537
		538	=item aio_nop $callback->()
		539
		540	This is a special request - it does nothing in itself and is only used for
		541	side effects, such as when you want to add a dummy request to a group so
		542	that finishing the requests in the group depends on executing the given
		543	code.
		544
		545	While this request does nothing, it still goes through the execution
		546	phase and still requires a worker thread. Thus, the callback will not
		547	be executed immediately but only after other requests in the queue have
		548	entered their execution phase. This can be used to measure request
		549	latency.
531		550
532	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	551	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED
533		552
534	Mainly used for debugging and benchmarking, this aio request puts one of	553	Mainly used for debugging and benchmarking, this aio request puts one of
535	the request workers to sleep for the given time.	554	the request workers to sleep for the given time.
…		…
585	You add requests by calling the C<add> method with one or more	604	You add requests by calling the C<add> method with one or more
586	C<IO::AIO::REQ> objects:	605	C<IO::AIO::REQ> objects:
587		606
588	$grp->add (aio_unlink "...");	607	$grp->add (aio_unlink "...");
589		608
590	add $grp aio_stat "...", sub { ... };	609	add $grp aio_stat "...", sub {
		610	$_[0] or return $grp->result ("error");
		611
		612	# add another request dynamically, if first succeeded
		613	add $grp aio_open "...", sub {
		614	$grp->result ("ok");
		615	};
		616	};
591		617
592	This makes it very easy to create composite requests (see the source of	618	This makes it very easy to create composite requests (see the source of
593	C<aio_move> for an application) that work and feel like simple requests.	619	C<aio_move> for an application) that work and feel like simple requests.
594		620
		621	=over 4
		622
595	The IO::AIO::GRP objects will be cleaned up during calls to	623	=item * The IO::AIO::GRP objects will be cleaned up during calls to
596	C<IO::AIO::poll_cb>, just like any other request.	624	C<IO::AIO::poll_cb>, just like any other request.
597		625
598	They can be canceled like any other request. Canceling will cancel not	626	=item * They can be canceled like any other request. Canceling will cancel not
599	just the request itself, but also all requests it contains.	627	only the request itself, but also all requests it contains.
600		628
601	They can also can also be added to other IO::AIO::GRP objects.	629	=item * They can also can also be added to other IO::AIO::GRP objects.
		630
		631	=item * You must not add requests to a group from within the group callback (or
		632	any later time).
		633
		634	=item * This does not harmonise well with C<max_outstanding>, so best do
		635	not combine C<aio_group> with it. Groups and feeders are recommended for
		636	this kind of concurrency-limiting.
		637
		638	=back
602		639
603	Their lifetime, simplified, looks like this: when they are empty, they	640	Their lifetime, simplified, looks like this: when they are empty, they
604	will finish very quickly. If they contain only requests that are in the	641	will finish very quickly. If they contain only requests that are in the
605	C<done> state, they will also finish. Otherwise they will continue to	642	C<done> state, they will also finish. Otherwise they will continue to
606	exist.	643	exist.
607		644
		645	That means after creating a group you have some time to add requests. And
		646	in the callbacks of those requests, you can add further requests to the
		647	group. And only when all those requests have finished will the the group
		648	itself finish.
		649
608	=over 4	650	=over 4
609		651
610	=item $grp->add (...)	652	=item $grp->add (...)
611		653
612	=item add $grp ...	654	=item add $grp ...
613		655
614	Add one or more	656	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
615	Cancels the request, if possible. Has the effect of skipping execution	657	be added, including other groups, as long as you do not create circular
616	when entering the B<execute> state and skipping calling the callback when	658	dependencies.
617	entering the the B<result> state, but will leave the request otherwise	659
618	untouched. That means that requests that currently execute will not be	660	Returns all its arguments.
619	stopped and resources held by the request will not be freed prematurely.	661
		662	=item $grp->result (...)
		663
		664	Set the result value(s) that will be passed to the group callback when all
		665	subrequests have finished. By default, no argument will be passed.
		666
		667	=item $grp->set_feeder ($callback->($grp))
		668
		669	[VERY EXPERIMENTAL]
		670
		671	Sets a feeder/generator on this group: every group can have an attached
		672	generator that generates requests if idle. The idea behind this is that,
		673	although you could just queue as many requests as you want in a group,
		674	this might starve other requests for a potentially long time. For
		675	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
		676	requests, delaying any later requests for a long time.
		677
		678	To avoid this, and allow incremental generation of requests, you can
		679	instead a group and set a feeder on it that generates those requests. The
		680	feeder will be called whenever there are few enough (see C<feeder_limit>,
		681	below) requests active in the group itself and is expected to queue more
		682	requests.
		683
		684	The feeder can queue as many requests as it likes (i.e. C<add> does not
		685	impose any limits).
		686
		687	If the feeder does not queue more requests when called, it will be
		688	automatically removed from the group.
		689
		690	If the feeder limit is C<0>, it will be set to C<2> automatically.
		691
		692	Example:
		693
		694	# stat all files in @files, but only ever use four aio requests concurrently:
		695
		696	my $grp = aio_group sub { print "finished\n" };
		697	$grp->feeder_limit (4);
		698	$grp->set_feeder (sub {
		699	my $file = pop @files
		700	or return;
		701
		702	add $grp aio_stat $file, sub { ... };
		703	});
		704
		705	=item $grp->feeder_limit ($num)
		706
		707	Sets the feeder limit for the group: The feeder will be called whenever
		708	the group contains less than this many requests.
		709
		710	Setting the limit to C<0> will pause the feeding process.
620		711
621	=back	712	=back
622		713
623	=head2 SUPPORT FUNCTIONS	714	=head2 SUPPORT FUNCTIONS
624		715
…		…
682	IO::AIO::poll_wait, IO::AIO::poll_cb	773	IO::AIO::poll_wait, IO::AIO::poll_cb
683	if IO::AIO::nreqs;	774	if IO::AIO::nreqs;
684		775
685	=item IO::AIO::min_parallel $nthreads	776	=item IO::AIO::min_parallel $nthreads
686		777
687	Set the minimum number of AIO threads to C<$nthreads>. The current default	778	Set the minimum number of AIO threads to C<$nthreads>. The current
688	is C<4>, which means four asynchronous operations can be done at one time	779	default is C<8>, which means eight asynchronous operations can execute
689	(the number of outstanding operations, however, is unlimited).	780	concurrently at any one time (the number of outstanding requests,
		781	however, is unlimited).
690		782
691	IO::AIO starts threads only on demand, when an AIO request is queued and	783	IO::AIO starts threads only on demand, when an AIO request is queued and
692	no free thread exists.	784	no free thread exists.
693		785
694	It is recommended to keep the number of threads low, as some Linux	786	It is recommended to keep the number of threads relatively low, as some
695	kernel versions will scale negatively with the number of threads (higher	787	Linux kernel versions will scale negatively with the number of threads
696	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	788	(higher parallelity => MUCH higher latency). With current Linux 2.6
697	threads should be fine.	789	versions, 4-32 threads should be fine.
698		790
699	Under most circumstances you don't need to call this function, as the	791	Under most circumstances you don't need to call this function, as the
700	module selects a default that is suitable for low to moderate load.	792	module selects a default that is suitable for low to moderate load.
701		793
702	=item IO::AIO::max_parallel $nthreads	794	=item IO::AIO::max_parallel $nthreads
…		…
713		805
714	Under normal circumstances you don't need to call this function.	806	Under normal circumstances you don't need to call this function.
715		807
716	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	808	=item $oldnreqs = IO::AIO::max_outstanding $nreqs
717		809
		810	[DEPRECATED]
		811
718	Sets the maximum number of outstanding requests to C<$nreqs>. If you	812	Sets the maximum number of outstanding requests to C<$nreqs>. If you
719	try to queue up more than this number of requests, the caller will block until	813	try to queue up more than this number of requests, the caller will block until
720	some requests have been handled.	814	some requests have been handled.
721		815
722	The default is very large, so normally there is no practical limit. If you	816	The default is very large, so normally there is no practical limit. If you
723	queue up many requests in a loop it often improves speed if you set	817	queue up many requests in a loop it often improves speed if you set
724	this to a relatively low number, such as C<100>.	818	this to a relatively low number, such as C<100>.
		819
		820	This function does not work well together with C<aio_group>'s, and their
		821	feeder interface is better suited to limiting concurrency, so do not use
		822	this function.
725		823
726	Under normal circumstances you don't need to call this function.	824	Under normal circumstances you don't need to call this function.
727		825
728	=back	826	=back
729		827
…		…
743	or return undef;	841	or return undef;
744		842
745	*$sym	843	*$sym
746	}	844	}
747		845
748	min_parallel 4;	846	min_parallel 8;
749		847
750	END {	848	END {
751	max_parallel 0;	849	max_parallel 0;
752	}	850	}
753		851
…		…
767		865
768	In short: the parent will, after a short pause, continue as if fork had	866	In short: the parent will, after a short pause, continue as if fork had
769	not been called, while the child will act as if IO::AIO has not been used	867	not been called, while the child will act as if IO::AIO has not been used
770	yet.	868	yet.
771		869
		870	=head2 MEMORY USAGE
		871
		872	Each aio request uses - depending on your architecture - around 128 bytes
		873	of memory. In addition, stat requests need a stat buffer (possibly a few
		874	hundred bytes). Perl scalars and other data passed into aio requests will
		875	also be locked.
		876
		877	This is now awfully much, so queuing lots of requests is not usually a
		878	problem.
		879
		880	Each thread needs a stack area which is usually around 16k, sometimes much
		881	larger, depending on the OS.
		882
772	=head1 SEE ALSO	883	=head1 SEE ALSO
773		884
774	L<Coro>, L<Linux::AIO> (obsolete).	885	L<Coro>, L<Linux::AIO> (obsolete).
775		886
776	=head1 AUTHOR	887	=head1 AUTHOR

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.56 by root, Sun Oct 22 00:53:47 2006 UTC vs. Revision 1.64 by root, Mon Oct 23 00:50:10 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.56 by root, Sun Oct 22 00:53:47 2006 UTC vs.
Revision 1.64 by root, Mon Oct 23 00:50:10 2006 UTC