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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs.
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC

…		…
51	=head1 DESCRIPTION	51	=head1 DESCRIPTION
52		52
53	This module implements asynchronous I/O using whatever means your	53	This module implements asynchronous I/O using whatever means your
54	operating system supports.	54	operating system supports.
55		55
56	Currently, a number of threads are started that execute your read/writes	56	In this version, a number of threads are started that execute your
57	and signal their completion. You don't need thread support in perl, and	57	requests and signal their completion. You don't need thread support
58	the threads created by this module will not be visible to perl. In the	58	in perl, and the threads created by this module will not be visible
59	future, this module might make use of the native aio functions available	59	to perl. In the future, this module might make use of the native aio
60	on many operating systems. However, they are often not well-supported	60	functions available on many operating systems. However, they are often
61	(Linux doesn't allow them on normal files currently, for example),	61	not well-supported or restricted (Linux doesn't allow them on normal
62	and they would only support aio_read and aio_write, so the remaining	62	files currently, for example), and they would only support aio_read and
63	functionality would have to be implemented using threads anyway.	63	aio_write, so the remaining functionality would have to be implemented
		64	using threads anyway.
64		65
65	Although the module will work with in the presence of other threads,	66	Although the module will work with in the presence of other (Perl-)
66	it is currently not reentrant in any way, so use appropriate locking	67	threads, it is currently not reentrant in any way, so use appropriate
67	yourself, always call C<poll_cb> from within the same thread, or never	68	locking yourself, always call C<poll_cb> from within the same thread, or
68	call C<poll_cb> (or other C<aio_> functions) recursively.	69	never call C<poll_cb> (or other C<aio_> functions) recursively.
		70
		71	=head1 REQUEST ANATOMY AND LIFETIME
		72
		73	Every C<aio_*> function creates a request. which is a C data structure not
		74	directly visible to Perl.
		75
		76	If called in non-void context, every request function returns a Perl
		77	object representing the request. In void context, nothing is returned,
		78	which saves a bit of memory.
		79
		80	The perl object is a fairly standard ref-to-hash object. The hash contents
		81	are not used by IO::AIO so you are free to store anything you like in it.
		82
		83	During their existance, aio requests travel through the following states,
		84	in order:
		85
		86	=over 4
		87
		88	=item ready
		89
		90	Immediately after a request is created it is put into the ready state,
		91	waiting for a thread to execute it.
		92
		93	=item execute
		94
		95	A thread has accepted the request for processing and is currently
		96	executing it (e.g. blocking in read).
		97
		98	=item pending
		99
		100	The request has been executed and is waiting for result processing.
		101
		102	While request submission and execution is fully asynchronous, result
		103	processing is not and relies on the perl interpreter calling C<poll_cb>
		104	(or another function with the same effect).
		105
		106	=item result
		107
		108	The request results are processed synchronously by C<poll_cb>.
		109
		110	The C<poll_cb> function will process all outstanding aio requests by
		111	calling their callbacks, freeing memory associated with them and managing
		112	any groups they are contained in.
		113
		114	=item done
		115
		116	Request has reached the end of its lifetime and holds no resources anymore
		117	(except possibly for the Perl object, but its connection to the actual
		118	aio request is severed and calling its methods will either do nothing or
		119	result in a runtime error).
69		120
70	=cut	121	=cut
71		122
72	package IO::AIO;	123	package IO::AIO;
73		124
…		…
80	our $VERSION = '2.0';	131	our $VERSION = '2.0';
81		132
82	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
83	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
84	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
85	aio_group aio_nop);	136	aio_copy aio_group aio_nop aio_mknod);
86	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
87	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
88	min_parallel max_parallel max_outstanding nreqs);	139	min_parallel max_parallel nreqs nready npending);
89		140
90	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
91		142
92	require XSLoader;	143	require XSLoader;
93	XSLoader::load ("IO::AIO", $VERSION);	144	XSLoader::load ("IO::AIO", $VERSION);
…		…
124	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
125	use something else.	176	use something else.
126		177
127	=over 4	178	=over 4
128		179
129	=item aioreq_pri $pri	180	=item $prev_pri = aioreq_pri [$pri]
130		181
131	Sets the priority for the next aio request. The default priority	182	Returns the priority value that would be used for the next request and, if
		183	C<$pri> is given, sets the priority for the next aio request.
		184
132	is C<0>, the minimum and maximum priorities are C<-4> and C<4>,	185	The default priority is C<0>, the minimum and maximum priorities are C<-4>
133	respectively. Requests with higher priority will be serviced first.	186	and C<4>, respectively. Requests with higher priority will be serviced
		187	first.
134		188
135	The priority will be reset to C<0> after each call to one of the C<aio_>	189	The priority will be reset to C<0> after each call to one of the C<aio_*>
136	functions.	190	functions.
137		191
138	Example: open a file with low priority, then read something from it with	192	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	193	higher priority so the read request is serviced before other low priority
140	open requests (potentially spamming the cache):	194	open requests (potentially spamming the cache):
…		…
210		264
211	aio_read $fh, 7, 15, $buffer, 0, sub {	265	aio_read $fh, 7, 15, $buffer, 0, sub {
212	$_[0] > 0 or die "read error: $!";	266	$_[0] > 0 or die "read error: $!";
213	print "read $_[0] bytes: <$buffer>\n";	267	print "read $_[0] bytes: <$buffer>\n";
214	};	268	};
215
216	=item aio_move $srcpath, $dstpath, $callback->($status)
217
218	Try to move the I<file> (directories not supported as either source or
219	destination) from C<$srcpath> to C<$dstpath> and call the callback with
220	the C<0> (error) or C<-1> ok.
221
222	This is a composite request that tries to rename(2) the file first. If
223	rename files with C<EXDEV>, it creates the destination file with mode 0200
224	and copies the contents of the source file into it using C<aio_sendfile>,
225	followed by restoring atime, mtime, access mode and uid/gid, in that
226	order, and unlinking the C<$srcpath>.
227
228	If an error occurs, the partial destination file will be unlinked, if
229	possible, except when setting atime, mtime, access mode and uid/gid, where
230	errors are being ignored.
231
232	=cut
233
234	sub aio_move($$$) {
235	my ($src, $dst, $cb) = @_;
236
237	my $grp = aio_group $cb;
238
239	add $grp aio_rename $src, $dst, sub {
240	if ($_[0] && $! == EXDEV) {
241	add $grp aio_open $src, O_RDONLY, 0, sub {
242	if (my $src_fh = $_[0]) {
243	my @stat = stat $src_fh;
244
245	add $grp aio_open $dst, O_WRONLY, 0200, sub {
246	if (my $dst_fh = $_[0]) {
247	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
248	close $src_fh;
249
250	if ($_[0] == $stat[7]) {
251	utime $stat[8], $stat[9], $dst;
252	chmod $stat[2] & 07777, $dst_fh;
253	chown $stat[4], $stat[5], $dst_fh;
254	close $dst_fh;
255
256	add $grp aio_unlink $src, sub {
257	$grp->result ($_[0]);
258	};
259	} else {
260	my $errno = $!;
261	add $grp aio_unlink $dst, sub {
262	$! = $errno;
263	$grp->result (-1);
264	};
265	}
266	};
267	} else {
268	$grp->result (-1);
269	}
270	},
271
272	} else {
273	$grp->result (-1);
274	}
275	};
276	} else {
277	$grp->result ($_[0]);
278	}
279	};
280
281	$grp
282	}
283		269
284	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	270	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
285		271
286	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	272	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
287	reading at byte offset C<$in_offset>, and starts writing at the current	273	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
343	=item aio_unlink $pathname, $callback->($status)	329	=item aio_unlink $pathname, $callback->($status)
344		330
345	Asynchronously unlink (delete) a file and call the callback with the	331	Asynchronously unlink (delete) a file and call the callback with the
346	result code.	332	result code.
347		333
		334	=item aio_mknod $path, $mode, $dev, $callback->($status)
		335
		336	Asynchronously create a device node (or fifo). See mknod(2): the only
		337	portable value for C<$mode> is C<S_IFIFO> ored with permissions, and C<0>
		338	for C<$dev>.
		339
348	=item aio_link $srcpath, $dstpath, $callback->($status)	340	=item aio_link $srcpath, $dstpath, $callback->($status)
349		341
350	Asynchronously create a new link to the existing object at C<$srcpath> at	342	Asynchronously create a new link to the existing object at C<$srcpath> at
351	the path C<$dstpath> and call the callback with the result code.	343	the path C<$dstpath> and call the callback with the result code.
352		344
…		…
372	sorted, and will B<NOT> include the C<.> and C<..> entries.	364	sorted, and will B<NOT> include the C<.> and C<..> entries.
373		365
374	The callback a single argument which is either C<undef> or an array-ref	366	The callback a single argument which is either C<undef> or an array-ref
375	with the filenames.	367	with the filenames.
376		368
		369	=item aio_copy $srcpath, $dstpath, $callback->($status)
		370
		371	Try to copy the I<file> (directories not supported as either source or
		372	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		373	the C<0> (error) or C<-1> ok.
		374
		375	This is a composite request that it creates the destination file with
		376	mode 0200 and copies the contents of the source file into it using
		377	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		378	uid/gid, in that order.
		379
		380	If an error occurs, the partial destination file will be unlinked, if
		381	possible, except when setting atime, mtime, access mode and uid/gid, where
		382	errors are being ignored.
		383
		384	=cut
		385
		386	sub aio_copy($$;$) {
		387	my ($src, $dst, $cb) = @_;
		388
		389	my $pri = aioreq_pri;
		390	my $grp = aio_group $cb;
		391
		392	aioreq_pri $pri;
		393	add $grp aio_open $src, O_RDONLY, 0, sub {
		394	if (my $src_fh = $_[0]) {
		395	my @stat = stat $src_fh;
		396
		397	aioreq_pri $pri;
		398	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		399	if (my $dst_fh = $_[0]) {
		400	aioreq_pri $pri;
		401	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		402	if ($_[0] == $stat[7]) {
		403	$grp->result (0);
		404	close $src_fh;
		405
		406	# those should not normally block. should. should.
		407	utime $stat[8], $stat[9], $dst;
		408	chmod $stat[2] & 07777, $dst_fh;
		409	chown $stat[4], $stat[5], $dst_fh;
		410	close $dst_fh;
		411	} else {
		412	$grp->result (-1);
		413	close $src_fh;
		414	close $dst_fh;
		415
		416	aioreq $pri;
		417	add $grp aio_unlink $dst;
		418	}
		419	};
		420	} else {
		421	$grp->result (-1);
		422	}
		423	},
		424
		425	} else {
		426	$grp->result (-1);
		427	}
		428	};
		429
		430	$grp
		431	}
		432
		433	=item aio_move $srcpath, $dstpath, $callback->($status)
		434
		435	Try to move the I<file> (directories not supported as either source or
		436	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		437	the C<0> (error) or C<-1> ok.
		438
		439	This is a composite request that tries to rename(2) the file first. If
		440	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		441	that is successful, unlinking the C<$srcpath>.
		442
		443	=cut
		444
		445	sub aio_move($$;$) {
		446	my ($src, $dst, $cb) = @_;
		447
		448	my $pri = aioreq_pri;
		449	my $grp = aio_group $cb;
		450
		451	aioreq_pri $pri;
		452	add $grp aio_rename $src, $dst, sub {
		453	if ($_[0] && $! == EXDEV) {
		454	aioreq_pri $pri;
		455	add $grp aio_copy $src, $dst, sub {
		456	$grp->result ($_[0]);
		457
		458	if (!$_[0]) {
		459	aioreq_pri $pri;
		460	add $grp aio_unlink $src;
		461	}
		462	};
		463	} else {
		464	$grp->result ($_[0]);
		465	}
		466	};
		467
		468	$grp
		469	}
		470
377	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	471	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
378		472
379	Scans a directory (similar to C<aio_readdir>) but additionally tries to	473	Scans a directory (similar to C<aio_readdir>) but additionally tries to
380	separate the entries of directory C<$path> into two sets of names, ones	474	efficiently separate the entries of directory C<$path> into two sets of
381	you can recurse into (directories or links to them), and ones you cannot	475	names, directories you can recurse into (directories), and ones you cannot
382	recurse into (everything else).	476	recurse into (everything else, including symlinks to directories).
383		477
384	C<aio_scandir> is a composite request that creates of many sub requests_	478	C<aio_scandir> is a composite request that creates of many sub requests_
385	C<$maxreq> specifies the maximum number of outstanding aio requests that	479	C<$maxreq> specifies the maximum number of outstanding aio requests that
386	this function generates. If it is C<< <= 0 >>, then a suitable default	480	this function generates. If it is C<< <= 0 >>, then a suitable default
387	will be chosen (currently 6).	481	will be chosen (currently 4).
388		482
389	On error, the callback is called without arguments, otherwise it receives	483	On error, the callback is called without arguments, otherwise it receives
390	two array-refs with path-relative entry names.	484	two array-refs with path-relative entry names.
391		485
392	Example:	486	Example:
…		…
429	=cut	523	=cut
430		524
431	sub aio_scandir($$$) {	525	sub aio_scandir($$$) {
432	my ($path, $maxreq, $cb) = @_;	526	my ($path, $maxreq, $cb) = @_;
433		527
		528	my $pri = aioreq_pri;
		529
434	my $grp = aio_group $cb;	530	my $grp = aio_group $cb;
435		531
436	$maxreq = 6 if $maxreq <= 0;	532	$maxreq = 4 if $maxreq <= 0;
437		533
438	# stat once	534	# stat once
		535	aioreq_pri $pri;
439	add $grp aio_stat $path, sub {	536	add $grp aio_stat $path, sub {
440	return $grp->result () if $_[0];	537	return $grp->result () if $_[0];
441	my $now = time;	538	my $now = time;
442	my $hash1 = join ":", (stat _)[0,1,3,7,9];	539	my $hash1 = join ":", (stat _)[0,1,3,7,9];
443		540
444	# read the directory entries	541	# read the directory entries
		542	aioreq_pri $pri;
445	add $grp aio_readdir $path, sub {	543	add $grp aio_readdir $path, sub {
446	my $entries = shift	544	my $entries = shift
447	or return $grp->result ();	545	or return $grp->result ();
448		546
449	# stat the dir another time	547	# stat the dir another time
		548	aioreq_pri $pri;
450	add $grp aio_stat $path, sub {	549	add $grp aio_stat $path, sub {
451	my $hash2 = join ":", (stat _)[0,1,3,7,9];	550	my $hash2 = join ":", (stat _)[0,1,3,7,9];
452		551
453	my $ndirs;	552	my $ndirs;
454		553
…		…
469	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	568	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
470	@$entries];	569	@$entries];
471		570
472	my (@dirs, @nondirs);	571	my (@dirs, @nondirs);
473		572
474	my ($statcb, $schedcb);
475	my $nreq = 0;
476
477	my $statgrp = add $grp aio_group;	573	my $statgrp = add $grp aio_group sub {
		574	$grp->result (\@dirs, \@nondirs);
		575	};
478		576
479	$schedcb = sub {	577	limit $statgrp $maxreq;
480	if (@$entries) {	578	feed $statgrp sub {
481	if ($nreq < $maxreq) {	579	return unless @$entries;
482	my $ent = pop @$entries;	580	my $entry = pop @$entries;
		581
		582	aioreq_pri $pri;
		583	add $statgrp aio_stat "$path/$entry/.", sub {
		584	if ($_[0] < 0) {
		585	push @nondirs, $entry;
		586	} else {
		587	# need to check for real directory
		588	aioreq_pri $pri;
		589	add $statgrp aio_lstat "$path/$entry", sub {
		590	if (-d _) {
		591	push @dirs, $entry;
		592
		593	unless (--$ndirs) {
		594	push @nondirs, @$entries;
		595	feed $statgrp;
		596	}
		597	} else {
		598	push @nondirs, $entry;
		599	}
483	$nreq++;	600	}
484	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
485	}	601	}
486	} elsif (!$nreq) {
487	# finished
488	$statgrp->cancel;
489	undef $statcb;
490	undef $schedcb;
491	$grp->result (\@dirs, \@nondirs);
492	}	602	};
493	};	603	};
494	$statcb = sub {
495	my ($status, $entry) = @_;
496
497	if ($status < 0) {
498	$nreq--;
499	push @nondirs, $entry;
500	&$schedcb;
501	} else {
502	# need to check for real directory
503	add $grp aio_lstat "$path/$entry", sub {
504	$nreq--;
505
506	if (-d _) {
507	push @dirs, $entry;
508
509	if (!--$ndirs) {
510	push @nondirs, @$entries;
511	$entries = [];
512	}
513	} else {
514	push @nondirs, $entry;
515	}
516
517	&$schedcb;
518	}
519	}
520	};
521
522	&$schedcb while @$entries && $nreq < $maxreq;
523	};	604	};
524	};	605	};
525	};	606	};
526		607
527	$grp	608	$grp
…		…
539		620
540	If this call isn't available because your OS lacks it or it couldn't be	621	If this call isn't available because your OS lacks it or it couldn't be
541	detected, it will be emulated by calling C<fsync> instead.	622	detected, it will be emulated by calling C<fsync> instead.
542		623
543	=item aio_group $callback->(...)	624	=item aio_group $callback->(...)
544
545	[EXPERIMENTAL]
546		625
547	This is a very special aio request: Instead of doing something, it is a	626	This is a very special aio request: Instead of doing something, it is a
548	container for other aio requests, which is useful if you want to bundle	627	container for other aio requests, which is useful if you want to bundle
549	many requests into a single, composite, request with a definite callback	628	many requests into a single, composite, request with a definite callback
550	and the ability to cancel the whole request with its subrequests.	629	and the ability to cancel the whole request with its subrequests.
…		…
591	=head2 IO::AIO::REQ CLASS	670	=head2 IO::AIO::REQ CLASS
592		671
593	All non-aggregate C<aio_*> functions return an object of this class when	672	All non-aggregate C<aio_*> functions return an object of this class when
594	called in non-void context.	673	called in non-void context.
595		674
596	A request always moves through the following five states in its lifetime,
597	in order: B<ready> (request has been created, but has not been executed
598	yet), B<execute> (request is currently being executed), B<pending>
599	(request has been executed but callback has not been called yet),
600	B<result> (results are being processed synchronously, includes calling the
601	callback) and B<done> (request has reached the end of its lifetime and
602	holds no resources anymore).
603
604	=over 4	675	=over 4
605		676
606	=item cancel $req	677	=item cancel $req
607		678
608	Cancels the request, if possible. Has the effect of skipping execution	679	Cancels the request, if possible. Has the effect of skipping execution
…		…
661	=item * They can also can also be added to other IO::AIO::GRP objects.	732	=item * They can also can also be added to other IO::AIO::GRP objects.
662		733
663	=item * You must not add requests to a group from within the group callback (or	734	=item * You must not add requests to a group from within the group callback (or
664	any later time).	735	any later time).
665		736
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	737	=back
671		738
672	Their lifetime, simplified, looks like this: when they are empty, they	739	Their lifetime, simplified, looks like this: when they are empty, they
673	will finish very quickly. If they contain only requests that are in the	740	will finish very quickly. If they contain only requests that are in the
674	C<done> state, they will also finish. Otherwise they will continue to	741	C<done> state, they will also finish. Otherwise they will continue to
…		…
689	be added, including other groups, as long as you do not create circular	756	be added, including other groups, as long as you do not create circular
690	dependencies.	757	dependencies.
691		758
692	Returns all its arguments.	759	Returns all its arguments.
693		760
		761	=item $grp->cancel_subs
		762
		763	Cancel all subrequests and clears any feeder, but not the group request
		764	itself. Useful when you queued a lot of events but got a result early.
		765
694	=item $grp->result (...)	766	=item $grp->result (...)
695		767
696	Set the result value(s) that will be passed to the group callback when all	768	Set the result value(s) that will be passed to the group callback when all
697	subrequests have finished. By default, no argument will be passed.	769	subrequests have finished and set thre groups errno to the current value
		770	of errno (just like calling C<errno> without an error number). By default,
		771	no argument will be passed and errno is zero.
		772
		773	=item $grp->errno ([$errno])
		774
		775	Sets the group errno value to C<$errno>, or the current value of errno
		776	when the argument is missing.
		777
		778	Every aio request has an associated errno value that is restored when
		779	the callback is invoked. This method lets you change this value from its
		780	default (0).
		781
		782	Calling C<result> will also set errno, so make sure you either set C<$!>
		783	before the call to C<result>, or call c<errno> after it.
698		784
699	=item feed $grp $callback->($grp)	785	=item feed $grp $callback->($grp)
700
701	[VERY EXPERIMENTAL]
702		786
703	Sets a feeder/generator on this group: every group can have an attached	787	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,	788	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,	789	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	790	this might starve other requests for a potentially long time. For
…		…
760		844
761	Process all outstanding events on the result pipe. You have to call this	845	Process all outstanding events on the result pipe. You have to call this
762	regularly. Returns the number of events processed. Returns immediately	846	regularly. Returns the number of events processed. Returns immediately
763	when no events are outstanding.	847	when no events are outstanding.
764		848
		849	If not all requests were processed for whatever reason, the filehandle
		850	will still be ready when C<poll_cb> returns.
		851
765	Example: Install an Event watcher that automatically calls	852	Example: Install an Event watcher that automatically calls
766	IO::AIO::poll_cb with high priority:	853	IO::AIO::poll_cb with high priority:
767		854
768	Event->io (fd => IO::AIO::poll_fileno,	855	Event->io (fd => IO::AIO::poll_fileno,
769	poll => 'r', async => 1,	856	poll => 'r', async => 1,
770	cb => \&IO::AIO::poll_cb);	857	cb => \&IO::AIO::poll_cb);
771		858
		859	=item IO::AIO::poll_some $max_requests
		860
		861	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests
		862	at a time.
		863
		864	Useful if you want to ensure some level of interactiveness when perl is
		865	not fast enough to process all requests in time.
		866
		867	Example: Install an Event watcher that automatically calls
		868	IO::AIO::poll_some with low priority, to ensure that other parts of the
		869	program get the CPU sometimes even under high AIO load.
		870
		871	Event->io (fd => IO::AIO::poll_fileno,
		872	poll => 'r', nice => 1,
		873	cb => sub { IO::AIO::poll_some 256 });
		874
772	=item IO::AIO::poll_wait	875	=item IO::AIO::poll_wait
773		876
774	Wait till the result filehandle becomes ready for reading (simply does a	877	Wait till the result filehandle becomes ready for reading (simply does a
775	C<select> on the filehandle. This is useful if you want to synchronously wait	878	C<select> on the filehandle. This is useful if you want to synchronously wait
776	for some requests to finish).	879	for some requests to finish).
777		880
778	See C<nreqs> for an example.	881	See C<nreqs> for an example.
779		882
780	=item IO::AIO::nreqs	883	=item IO::AIO::nreqs
781		884
782	Returns the number of requests currently outstanding (i.e. for which their	885	Returns the number of requests currently in the ready, execute or pending
783	callback has not been invoked yet).	886	states (i.e. for which their callback has not been invoked yet).
784		887
785	Example: wait till there are no outstanding requests anymore:	888	Example: wait till there are no outstanding requests anymore:
786		889
787	IO::AIO::poll_wait, IO::AIO::poll_cb	890	IO::AIO::poll_wait, IO::AIO::poll_cb
788	while IO::AIO::nreqs;	891	while IO::AIO::nreqs;
		892
		893	=item IO::AIO::nready
		894
		895	Returns the number of requests currently in the ready state (not yet
		896	executed).
		897
		898	=item IO::AIO::npending
		899
		900	Returns the number of requests currently in the pending state (executed,
		901	but not yet processed by poll_cb).
789		902
790	=item IO::AIO::flush	903	=item IO::AIO::flush
791		904
792	Wait till all outstanding AIO requests have been handled.	905	Wait till all outstanding AIO requests have been handled.
793		906
…		…
835	This module automatically runs C<max_parallel 0> at program end, to ensure	948	This module automatically runs C<max_parallel 0> at program end, to ensure
836	that all threads are killed and that there are no outstanding requests.	949	that all threads are killed and that there are no outstanding requests.
837		950
838	Under normal circumstances you don't need to call this function.	951	Under normal circumstances you don't need to call this function.
839		952
840	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	953	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
841		954
842	[DEPRECATED]	955	This is a very bad function to use in interactive programs because it
		956	blocks, and a bad way to reduce concurrency because it is inexact: Better
		957	use an C<aio_group> together with a feed callback.
843		958
844	Sets the maximum number of outstanding requests to C<$nreqs>. If you	959	Sets the maximum number of outstanding requests to C<$nreqs>. If you
845	try to queue up more than this number of requests, the caller will block until	960	to queue up more than this number of requests, the next call to the
846	some requests have been handled.	961	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		962	function will block until the limit is no longer exceeded.
847		963
848	The default is very large, so normally there is no practical limit. If you	964	The default value is very large, so there is no practical limit on the
849	queue up many requests in a loop it often improves speed if you set	965	number of outstanding requests.
850	this to a relatively low number, such as C<100>.
851		966
852	This function does not work well together with C<aio_group>'s, and their	967	You can still queue as many requests as you want. Therefore,
853	feeder interface is better suited to limiting concurrency, so do not use	968	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
854	this function.	969	as a stop gap to shield against fatal memory overflow (with large values).
855
856	Under normal circumstances you don't need to call this function.
857		970
858	=back	971	=back
859		972
860	=cut	973	=cut
861		974
…		…
876	}	989	}
877		990
878	min_parallel 8;	991	min_parallel 8;
879		992
880	END {	993	END {
881	max_parallel 0;	994	flush;
882	}	995	};
883		996
884	1;	997	1;
885		998
886	=head2 FORK BEHAVIOUR	999	=head2 FORK BEHAVIOUR
887		1000
888	This module should do "the right thing" when the process using it forks:	1001	This module should do "the right thing" when the process using it forks:
889		1002
890	Before the fork, IO::AIO enters a quiescent state where no requests	1003	Before the fork, IO::AIO enters a quiescent state where no requests
891	can be added in other threads and no results will be processed. After	1004	can be added in other threads and no results will be processed. After
892	the fork the parent simply leaves the quiescent state and continues	1005	the fork the parent simply leaves the quiescent state and continues
893	request/result processing, while the child clears the request/result	1006	request/result processing, while the child frees the request/result queue
894	queue (so the requests started before the fork will only be handled in	1007	(so that the requests started before the fork will only be handled in the
895	the parent). Threads will be started on demand until the limit ste in the	1008	parent). Threads will be started on demand until the limit set in the
896	parent process has been reached again.	1009	parent process has been reached again.
897		1010
898	In short: the parent will, after a short pause, continue as if fork had	1011	In short: the parent will, after a short pause, continue as if fork had
899	not been called, while the child will act as if IO::AIO has not been used	1012	not been called, while the child will act as if IO::AIO has not been used
900	yet.	1013	yet.
901		1014
902	=head2 MEMORY USAGE	1015	=head2 MEMORY USAGE
903		1016
		1017	Per-request usage:
		1018
904	Each aio request uses - depending on your architecture - around 128 bytes	1019	Each aio request uses - depending on your architecture - around 100-200
905	of memory. In addition, stat requests need a stat buffer (possibly a few	1020	bytes of memory. In addition, stat requests need a stat buffer (possibly
906	hundred bytes). Perl scalars and other data passed into aio requests will	1021	a few hundred bytes), readdir requires a result buffer and so on. Perl
907	also be locked.	1022	scalars and other data passed into aio requests will also be locked and
		1023	will consume memory till the request has entered the done state.
908		1024
909	This is now awfully much, so queuing lots of requests is not usually a	1025	This is now awfully much, so queuing lots of requests is not usually a
910	problem.	1026	problem.
911		1027
912	Each thread needs a stack area which is usually around 16k, sometimes much	1028	Per-thread usage:
913	larger, depending on the OS.	1029
		1030	In the execution phase, some aio requests require more memory for
		1031	temporary buffers, and each thread requires a stack and other data
		1032	structures (usually around 16k-128k, depending on the OS).
		1033
		1034	=head1 KNOWN BUGS
		1035
		1036	Known bugs will be fixed in the next release.
914		1037
915	=head1 SEE ALSO	1038	=head1 SEE ALSO
916		1039
917	L<Coro::AIO>.	1040	L<Coro::AIO>.
918		1041

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs. Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs.
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC