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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.60 by root, Sun Oct 22 13:33:28 2006 UTC vs.
Revision 1.94 by root, Wed Nov 8 02:01:02 2006 UTC

…		…
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
18	};	19	};
19		20
20	# version 2+ has request and group objects	21	# version 2+ has request and group objects
21	use IO::AIO 2;	22	use IO::AIO 2;
22		23
		24	aioreq_pri 4; # give next request a very high priority
23	my $req = aio_unlink "/tmp/file", sub { };	25	my $req = aio_unlink "/tmp/file", sub { };
24	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
25		27
26	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
27	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
…		…
50	=head1 DESCRIPTION	52	=head1 DESCRIPTION
51		53
52	This module implements asynchronous I/O using whatever means your	54	This module implements asynchronous I/O using whatever means your
53	operating system supports.	55	operating system supports.
54		56
		57	Asynchronous means that operations that can normally block your program
		58	(e.g. reading from disk) will be done asynchronously: the operation
		59	will still block, but you can do something else in the meantime. This
		60	is extremely useful for programs that need to stay interactive even
		61	when doing heavy I/O (GUI programs, high performance network servers
		62	etc.), but can also be used to easily do operations in parallel that are
		63	normally done sequentially, e.g. stat'ing many files, which is much faster
		64	on a RAID volume or over NFS when you do a number of stat operations
		65	concurrently.
		66
		67	While most of this works on all types of file descriptors (for example
		68	sockets), using these functions on file descriptors that support
		69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or
		70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop
		71	for that (such as the L<Event\|Event> module): IO::AIO will naturally fit
		72	into such an event loop itself.
		73
55	Currently, a number of threads are started that execute your read/writes	74	In this version, a number of threads are started that execute your
56	and signal their completion. You don't need thread support in your libc or	75	requests and signal their completion. You don't need thread support
57	perl, and the threads created by this module will not be visible to the	76	in perl, and the threads created by this module will not be visible
58	pthreads library. In the future, this module might make use of the native	77	to perl. In the future, this module might make use of the native aio
59	aio functions available on many operating systems. However, they are often	78	functions available on many operating systems. However, they are often
60	not well-supported (Linux doesn't allow them on normal files currently,	79	not well-supported or restricted (GNU/Linux doesn't allow them on normal
61	for example), and they would only support aio_read and aio_write, so the	80	files currently, for example), and they would only support aio_read and
62	remaining functionality would have to be implemented using threads anyway.	81	aio_write, so the remaining functionality would have to be implemented
		82	using threads anyway.
63		83
64	Although the module will work with in the presence of other threads, it is	84	Although the module will work with in the presence of other (Perl-)
65	currently not reentrant, so use appropriate locking yourself, always call	85	threads, it is currently not reentrant in any way, so use appropriate
66	C<poll_cb> from within the same thread, or never call C<poll_cb> (or other	86	locking yourself, always call C<poll_cb> from within the same thread, or
67	C<aio_> functions) recursively.	87	never call C<poll_cb> (or other C<aio_> functions) recursively.
		88
		89	=head2 EXAMPLE
		90
		91	This is a simple example that uses the Event module and loads
		92	F</etc/passwd> asynchronously:
		93
		94	use Fcntl;
		95	use Event;
		96	use IO::AIO;
		97
		98	# register the IO::AIO callback with Event
		99	Event->io (fd => IO::AIO::poll_fileno,
		100	poll => 'r',
		101	cb => \&IO::AIO::poll_cb);
		102
		103	# queue the request to open /etc/passwd
		104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		105	my $fh = shift
		106	or die "error while opening: $!";
		107
		108	# stat'ing filehandles is generally non-blocking
		109	my $size = -s $fh;
		110
		111	# queue a request to read the file
		112	my $contents;
		113	aio_read $fh, 0, $size, $contents, 0, sub {
		114	$_[0] == $size
		115	or die "short read: $!";
		116
		117	close $fh;
		118
		119	# file contents now in $contents
		120	print $contents;
		121
		122	# exit event loop and program
		123	Event::unloop;
		124	};
		125	};
		126
		127	# possibly queue up other requests, or open GUI windows,
		128	# check for sockets etc. etc.
		129
		130	# process events as long as there are some:
		131	Event::loop;
		132
		133	=head1 REQUEST ANATOMY AND LIFETIME
		134
		135	Every C<aio_*> function creates a request. which is a C data structure not
		136	directly visible to Perl.
		137
		138	If called in non-void context, every request function returns a Perl
		139	object representing the request. In void context, nothing is returned,
		140	which saves a bit of memory.
		141
		142	The perl object is a fairly standard ref-to-hash object. The hash contents
		143	are not used by IO::AIO so you are free to store anything you like in it.
		144
		145	During their existance, aio requests travel through the following states,
		146	in order:
		147
		148	=over 4
		149
		150	=item ready
		151
		152	Immediately after a request is created it is put into the ready state,
		153	waiting for a thread to execute it.
		154
		155	=item execute
		156
		157	A thread has accepted the request for processing and is currently
		158	executing it (e.g. blocking in read).
		159
		160	=item pending
		161
		162	The request has been executed and is waiting for result processing.
		163
		164	While request submission and execution is fully asynchronous, result
		165	processing is not and relies on the perl interpreter calling C<poll_cb>
		166	(or another function with the same effect).
		167
		168	=item result
		169
		170	The request results are processed synchronously by C<poll_cb>.
		171
		172	The C<poll_cb> function will process all outstanding aio requests by
		173	calling their callbacks, freeing memory associated with them and managing
		174	any groups they are contained in.
		175
		176	=item done
		177
		178	Request has reached the end of its lifetime and holds no resources anymore
		179	(except possibly for the Perl object, but its connection to the actual
		180	aio request is severed and calling its methods will either do nothing or
		181	result in a runtime error).
		182
		183	=back
68		184
69	=cut	185	=cut
70		186
71	package IO::AIO;	187	package IO::AIO;
72		188
…		…
74	use strict 'vars';	190	use strict 'vars';
75		191
76	use base 'Exporter';	192	use base 'Exporter';
77		193
78	BEGIN {	194	BEGIN {
79	our $VERSION = '2.0';	195	our $VERSION = '2.2';
80		196
81	our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	197	our @AIO_REQ = 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	198	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	199	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
84	aio_group);	200	aio_move aio_copy aio_group aio_nop aio_mknod);
85	our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
		202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
		203	min_parallel max_parallel max_idle
		204	nreqs nready npending nthreads
		205	max_poll_time max_poll_reqs);
86		206
87	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
88		208
89	require XSLoader;	209	require XSLoader;
90	XSLoader::load ("IO::AIO", $VERSION);	210	XSLoader::load ("IO::AIO", $VERSION);
91	}	211	}
92		212
93	=head1 FUNCTIONS	213	=head1 FUNCTIONS
94		214
95	=head2 AIO FUNCTIONS	215	=head2 AIO REQUEST FUNCTIONS
96		216
97	All the C<aio_*> calls are more or less thin wrappers around the syscall	217	All the C<aio_*> calls are more or less thin wrappers around the syscall
98	with the same name (sans C<aio_>). The arguments are similar or identical,	218	with the same name (sans C<aio_>). The arguments are similar or identical,
99	and they all accept an additional (and optional) C<$callback> argument	219	and they all accept an additional (and optional) C<$callback> argument
100	which must be a code reference. This code reference will get called with	220	which must be a code reference. This code reference will get called with
…		…
103	syscall has been executed asynchronously.	223	syscall has been executed asynchronously.
104		224
105	All functions expecting a filehandle keep a copy of the filehandle	225	All functions expecting a filehandle keep a copy of the filehandle
106	internally until the request has finished.	226	internally until the request has finished.
107		227
108	All requests return objects of type L<IO::AIO::REQ> that allow further	228	All functions return request objects of type L<IO::AIO::REQ> that allow
109	manipulation of those requests while they are in-flight.	229	further manipulation of those requests while they are in-flight.
110		230
111	The pathnames you pass to these routines I<must> be absolute and	231	The pathnames you pass to these routines I<must> be absolute and
112	encoded in byte form. The reason for the former is that at the time the	232	encoded as octets. The reason for the former is that at the time the
113	request is being executed, the current working directory could have	233	request is being executed, the current working directory could have
114	changed. Alternatively, you can make sure that you never change the	234	changed. Alternatively, you can make sure that you never change the
115	current working directory.	235	current working directory anywhere in the program and then use relative
		236	paths.
116		237
117	To encode pathnames to byte form, either make sure you either: a)	238	To encode pathnames as octets, either make sure you either: a) always pass
118	always pass in filenames you got from outside (command line, readdir	239	in filenames you got from outside (command line, readdir etc.) without
119	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	240	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
120	your pathnames to the locale (or other) encoding in effect in the user	241	your pathnames to the locale (or other) encoding in effect in the user
121	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	242	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
122	use something else.	243	use something else to ensure your scalar has the correct contents.
		244
		245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		246	handles correctly wether it is set or not.
123		247
124	=over 4	248	=over 4
		249
		250	=item $prev_pri = aioreq_pri [$pri]
		251
		252	Returns the priority value that would be used for the next request and, if
		253	C<$pri> is given, sets the priority for the next aio request.
		254
		255	The default priority is C<0>, the minimum and maximum priorities are C<-4>
		256	and C<4>, respectively. Requests with higher priority will be serviced
		257	first.
		258
		259	The priority will be reset to C<0> after each call to one of the C<aio_*>
		260	functions.
		261
		262	Example: open a file with low priority, then read something from it with
		263	higher priority so the read request is serviced before other low priority
		264	open requests (potentially spamming the cache):
		265
		266	aioreq_pri -3;
		267	aio_open ..., sub {
		268	return unless $_[0];
		269
		270	aioreq_pri -2;
		271	aio_read $_[0], ..., sub {
		272	...
		273	};
		274	};
		275
		276	=item aioreq_nice $pri_adjust
		277
		278	Similar to C<aioreq_pri>, but subtracts the given value from the current
		279	priority, so the effect is cumulative.
125		280
126	=item aio_open $pathname, $flags, $mode, $callback->($fh)	281	=item aio_open $pathname, $flags, $mode, $callback->($fh)
127		282
128	Asynchronously open or create a file and call the callback with a newly	283	Asynchronously open or create a file and call the callback with a newly
129	created filehandle for the file.	284	created filehandle for the file.
…		…
179		334
180	aio_read $fh, 7, 15, $buffer, 0, sub {	335	aio_read $fh, 7, 15, $buffer, 0, sub {
181	$_[0] > 0 or die "read error: $!";	336	$_[0] > 0 or die "read error: $!";
182	print "read $_[0] bytes: <$buffer>\n";	337	print "read $_[0] bytes: <$buffer>\n";
183	};	338	};
184
185	=item aio_move $srcpath, $dstpath, $callback->($status)
186
187	[EXPERIMENTAL due to internal aio_group use]
188
189	Try to move the I<file> (directories not supported as either source or
190	destination) from C<$srcpath> to C<$dstpath> and call the callback with
191	the C<0> (error) or C<-1> ok.
192
193	This is a composite request that tries to rename(2) the file first. If
194	rename files with C<EXDEV>, it creates the destination file with mode 0200
195	and copies the contents of the source file into it using C<aio_sendfile>,
196	followed by restoring atime, mtime, access mode and uid/gid, in that
197	order, and unlinking the C<$srcpath>.
198
199	If an error occurs, the partial destination file will be unlinked, if
200	possible, except when setting atime, mtime, access mode and uid/gid, where
201	errors are being ignored.
202
203	=cut
204
205	sub aio_move($$$) {
206	my ($src, $dst, $cb) = @_;
207
208	my $grp = aio_group $cb;
209
210	add $grp aio_rename $src, $dst, sub {
211	if ($_[0] && $! == EXDEV) {
212	add $grp aio_open $src, O_RDONLY, 0, sub {
213	if (my $src_fh = $_[0]) {
214	my @stat = stat $src_fh;
215
216	add $grp aio_open $dst, O_WRONLY, 0200, sub {
217	if (my $dst_fh = $_[0]) {
218	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
219	close $src_fh;
220
221	if ($_[0] == $stat[7]) {
222	utime $stat[8], $stat[9], $dst;
223	chmod $stat[2] & 07777, $dst_fh;
224	chown $stat[4], $stat[5], $dst_fh;
225	close $dst_fh;
226
227	add $grp aio_unlink $src, sub {
228	$grp->result ($_[0]);
229	};
230	} else {
231	my $errno = $!;
232	add $grp aio_unlink $dst, sub {
233	$! = $errno;
234	$grp->result (-1);
235	};
236	}
237	};
238	} else {
239	$grp->result (-1);
240	}
241	},
242
243	} else {
244	$grp->result (-1);
245	}
246	};
247	} else {
248	$grp->result ($_[0]);
249	}
250	};
251
252	$grp
253	}
254		339
255	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	340	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
256		341
257	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	342	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
258	reading at byte offset C<$in_offset>, and starts writing at the current	343	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
314	=item aio_unlink $pathname, $callback->($status)	399	=item aio_unlink $pathname, $callback->($status)
315		400
316	Asynchronously unlink (delete) a file and call the callback with the	401	Asynchronously unlink (delete) a file and call the callback with the
317	result code.	402	result code.
318		403
		404	=item aio_mknod $path, $mode, $dev, $callback->($status)
		405
		406	[EXPERIMENTAL]
		407
		408	Asynchronously create a device node (or fifo). See mknod(2).
		409
		410	The only (POSIX-) portable way of calling this function is:
		411
		412	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		413
319	=item aio_link $srcpath, $dstpath, $callback->($status)	414	=item aio_link $srcpath, $dstpath, $callback->($status)
320		415
321	Asynchronously create a new link to the existing object at C<$srcpath> at	416	Asynchronously create a new link to the existing object at C<$srcpath> at
322	the path C<$dstpath> and call the callback with the result code.	417	the path C<$dstpath> and call the callback with the result code.
323		418
324	=item aio_symlink $srcpath, $dstpath, $callback->($status)	419	=item aio_symlink $srcpath, $dstpath, $callback->($status)
325		420
326	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	421	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
327	the path C<$dstpath> and call the callback with the result code.	422	the path C<$dstpath> and call the callback with the result code.
		423
		424	=item aio_readlink $path, $callback->($link)
		425
		426	Asynchronously read the symlink specified by C<$path> and pass it to
		427	the callback. If an error occurs, nothing or undef gets passed to the
		428	callback.
328		429
329	=item aio_rename $srcpath, $dstpath, $callback->($status)	430	=item aio_rename $srcpath, $dstpath, $callback->($status)
330		431
331	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	432	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
332	rename(2) and call the callback with the result code.	433	rename(2) and call the callback with the result code.
…		…
343	sorted, and will B<NOT> include the C<.> and C<..> entries.	444	sorted, and will B<NOT> include the C<.> and C<..> entries.
344		445
345	The callback a single argument which is either C<undef> or an array-ref	446	The callback a single argument which is either C<undef> or an array-ref
346	with the filenames.	447	with the filenames.
347		448
		449	=item aio_copy $srcpath, $dstpath, $callback->($status)
		450
		451	Try to copy the I<file> (directories not supported as either source or
		452	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		453	the C<0> (error) or C<-1> ok.
		454
		455	This is a composite request that it creates the destination file with
		456	mode 0200 and copies the contents of the source file into it using
		457	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		458	uid/gid, in that order.
		459
		460	If an error occurs, the partial destination file will be unlinked, if
		461	possible, except when setting atime, mtime, access mode and uid/gid, where
		462	errors are being ignored.
		463
		464	=cut
		465
		466	sub aio_copy($$;$) {
		467	my ($src, $dst, $cb) = @_;
		468
		469	my $pri = aioreq_pri;
		470	my $grp = aio_group $cb;
		471
		472	aioreq_pri $pri;
		473	add $grp aio_open $src, O_RDONLY, 0, sub {
		474	if (my $src_fh = $_[0]) {
		475	my @stat = stat $src_fh;
		476
		477	aioreq_pri $pri;
		478	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		479	if (my $dst_fh = $_[0]) {
		480	aioreq_pri $pri;
		481	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		482	if ($_[0] == $stat[7]) {
		483	$grp->result (0);
		484	close $src_fh;
		485
		486	# those should not normally block. should. should.
		487	utime $stat[8], $stat[9], $dst;
		488	chmod $stat[2] & 07777, $dst_fh;
		489	chown $stat[4], $stat[5], $dst_fh;
		490	close $dst_fh;
		491	} else {
		492	$grp->result (-1);
		493	close $src_fh;
		494	close $dst_fh;
		495
		496	aioreq $pri;
		497	add $grp aio_unlink $dst;
		498	}
		499	};
		500	} else {
		501	$grp->result (-1);
		502	}
		503	},
		504
		505	} else {
		506	$grp->result (-1);
		507	}
		508	};
		509
		510	$grp
		511	}
		512
		513	=item aio_move $srcpath, $dstpath, $callback->($status)
		514
		515	Try to move the I<file> (directories not supported as either source or
		516	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		517	the C<0> (error) or C<-1> ok.
		518
		519	This is a composite request that tries to rename(2) the file first. If
		520	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		521	that is successful, unlinking the C<$srcpath>.
		522
		523	=cut
		524
		525	sub aio_move($$;$) {
		526	my ($src, $dst, $cb) = @_;
		527
		528	my $pri = aioreq_pri;
		529	my $grp = aio_group $cb;
		530
		531	aioreq_pri $pri;
		532	add $grp aio_rename $src, $dst, sub {
		533	if ($_[0] && $! == EXDEV) {
		534	aioreq_pri $pri;
		535	add $grp aio_copy $src, $dst, sub {
		536	$grp->result ($_[0]);
		537
		538	if (!$_[0]) {
		539	aioreq_pri $pri;
		540	add $grp aio_unlink $src;
		541	}
		542	};
		543	} else {
		544	$grp->result ($_[0]);
		545	}
		546	};
		547
		548	$grp
		549	}
		550
348	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	551	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
349		552
350	[EXPERIMENTAL due to internal aio_group use]
351
352	Scans a directory (similar to C<aio_readdir>) but additionally tries to	553	Scans a directory (similar to C<aio_readdir>) but additionally tries to
353	separate the entries of directory C<$path> into two sets of names, ones	554	efficiently separate the entries of directory C<$path> into two sets of
354	you can recurse into (directories or links to them), and ones you cannot	555	names, directories you can recurse into (directories), and ones you cannot
355	recurse into (everything else).	556	recurse into (everything else, including symlinks to directories).
356		557
357	C<aio_scandir> is a composite request that consists of many sub	558	C<aio_scandir> is a composite request that creates of many sub requests_
358	requests. C<$maxreq> specifies the maximum number of outstanding aio	559	C<$maxreq> specifies the maximum number of outstanding aio requests that
359	requests that this function generates. If it is C<< <= 0 >>, then a	560	this function generates. If it is C<< <= 0 >>, then a suitable default
360	suitable default will be chosen (currently 8).	561	will be chosen (currently 4).
361		562
362	On error, the callback is called without arguments, otherwise it receives	563	On error, the callback is called without arguments, otherwise it receives
363	two array-refs with path-relative entry names.	564	two array-refs with path-relative entry names.
364		565
365	Example:	566	Example:
…		…
402	=cut	603	=cut
403		604
404	sub aio_scandir($$$) {	605	sub aio_scandir($$$) {
405	my ($path, $maxreq, $cb) = @_;	606	my ($path, $maxreq, $cb) = @_;
406		607
		608	my $pri = aioreq_pri;
		609
407	my $grp = aio_group $cb;	610	my $grp = aio_group $cb;
408		611
409	$maxreq = 8 if $maxreq <= 0;	612	$maxreq = 4 if $maxreq <= 0;
410		613
411	# stat once	614	# stat once
		615	aioreq_pri $pri;
412	add $grp aio_stat $path, sub {	616	add $grp aio_stat $path, sub {
413	return $grp->result () if $_[0];	617	return $grp->result () if $_[0];
414	my $now = time;	618	my $now = time;
415	my $hash1 = join ":", (stat _)[0,1,3,7,9];	619	my $hash1 = join ":", (stat _)[0,1,3,7,9];
416		620
417	# read the directory entries	621	# read the directory entries
		622	aioreq_pri $pri;
418	add $grp aio_readdir $path, sub {	623	add $grp aio_readdir $path, sub {
419	my $entries = shift	624	my $entries = shift
420	or return $grp->result ();	625	or return $grp->result ();
421		626
422	# stat the dir another time	627	# stat the dir another time
		628	aioreq_pri $pri;
423	add $grp aio_stat $path, sub {	629	add $grp aio_stat $path, sub {
424	my $hash2 = join ":", (stat _)[0,1,3,7,9];	630	my $hash2 = join ":", (stat _)[0,1,3,7,9];
425		631
426	my $ndirs;	632	my $ndirs;
427		633
…		…
442	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	648	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
443	@$entries];	649	@$entries];
444		650
445	my (@dirs, @nondirs);	651	my (@dirs, @nondirs);
446		652
447	my ($statcb, $schedcb);
448	my $nreq = 0;
449
450	my $statgrp = add $grp aio_group;	653	my $statgrp = add $grp aio_group sub {
		654	$grp->result (\@dirs, \@nondirs);
		655	};
451		656
452	$schedcb = sub {	657	limit $statgrp $maxreq;
453	if (@$entries) {	658	feed $statgrp sub {
454	if ($nreq < $maxreq) {	659	return unless @$entries;
455	my $ent = pop @$entries;	660	my $entry = pop @$entries;
		661
		662	aioreq_pri $pri;
		663	add $statgrp aio_stat "$path/$entry/.", sub {
		664	if ($_[0] < 0) {
		665	push @nondirs, $entry;
		666	} else {
		667	# need to check for real directory
		668	aioreq_pri $pri;
		669	add $statgrp aio_lstat "$path/$entry", sub {
		670	if (-d _) {
		671	push @dirs, $entry;
		672
		673	unless (--$ndirs) {
		674	push @nondirs, @$entries;
		675	feed $statgrp;
		676	}
		677	} else {
		678	push @nondirs, $entry;
		679	}
456	$nreq++;	680	}
457	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
458	}	681	}
459	} elsif (!$nreq) {
460	# finished
461	$statgrp->cancel;
462	undef $statcb;
463	undef $schedcb;
464	$grp->result (\@dirs, \@nondirs);
465	}	682	};
466	};	683	};
467	$statcb = sub {
468	my ($status, $entry) = @_;
469
470	if ($status < 0) {
471	$nreq--;
472	push @nondirs, $entry;
473	&$schedcb;
474	} else {
475	# need to check for real directory
476	add $grp aio_lstat "$path/$entry", sub {
477	$nreq--;
478
479	if (-d _) {
480	push @dirs, $entry;
481
482	if (!--$ndirs) {
483	push @nondirs, @$entries;
484	$entries = [];
485	}
486	} else {
487	push @nondirs, $entry;
488	}
489
490	&$schedcb;
491	}
492	}
493	};
494
495	&$schedcb while @$entries && $nreq < $maxreq;
496	};	684	};
497	};	685	};
498	};	686	};
499		687
500	$grp	688	$grp
…		…
513	If this call isn't available because your OS lacks it or it couldn't be	701	If this call isn't available because your OS lacks it or it couldn't be
514	detected, it will be emulated by calling C<fsync> instead.	702	detected, it will be emulated by calling C<fsync> instead.
515		703
516	=item aio_group $callback->(...)	704	=item aio_group $callback->(...)
517		705
518	[EXPERIMENTAL]
519
520	This is a very special aio request: Instead of doing something, it is a	706	This is a very special aio request: Instead of doing something, it is a
521	container for other aio requests, which is useful if you want to bundle	707	container for other aio requests, which is useful if you want to bundle
522	many requests into a single, composite, request.	708	many requests into a single, composite, request with a definite callback
		709	and the ability to cancel the whole request with its subrequests.
523		710
524	Returns an object of class L<IO::AIO::GRP>. See its documentation below	711	Returns an object of class L<IO::AIO::GRP>. See its documentation below
525	for more info.	712	for more info.
526		713
527	Example:	714	Example:
…		…
533	add $grp	720	add $grp
534	(aio_stat ...),	721	(aio_stat ...),
535	(aio_stat ...),	722	(aio_stat ...),
536	...;	723	...;
537		724
		725	=item aio_nop $callback->()
		726
		727	This is a special request - it does nothing in itself and is only used for
		728	side effects, such as when you want to add a dummy request to a group so
		729	that finishing the requests in the group depends on executing the given
		730	code.
		731
		732	While this request does nothing, it still goes through the execution
		733	phase and still requires a worker thread. Thus, the callback will not
		734	be executed immediately but only after other requests in the queue have
		735	entered their execution phase. This can be used to measure request
		736	latency.
		737
538	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	738	=item IO::AIO::aio_busy $fractional_seconds, $callback->() NOT EXPORTED
539		739
540	Mainly used for debugging and benchmarking, this aio request puts one of	740	Mainly used for debugging and benchmarking, this aio request puts one of
541	the request workers to sleep for the given time.	741	the request workers to sleep for the given time.
542		742
543	While it is theoretically handy to have simple I/O scheduling requests	743	While it is theoretically handy to have simple I/O scheduling requests
544	like sleep and file handle readable/writable, the overhead this creates	744	like sleep and file handle readable/writable, the overhead this creates is
545	is immense, so do not use this function except to put your application	745	immense (it blocks a thread for a long time) so do not use this function
546	under artificial I/O pressure.	746	except to put your application under artificial I/O pressure.
547		747
548	=back	748	=back
549		749
550	=head2 IO::AIO::REQ CLASS	750	=head2 IO::AIO::REQ CLASS
551		751
552	All non-aggregate C<aio_*> functions return an object of this class when	752	All non-aggregate C<aio_*> functions return an object of this class when
553	called in non-void context.	753	called in non-void context.
554		754
555	A request always moves through the following five states in its lifetime,
556	in order: B<ready> (request has been created, but has not been executed
557	yet), B<execute> (request is currently being executed), B<pending>
558	(request has been executed but callback has not been called yet),
559	B<result> (results are being processed synchronously, includes calling the
560	callback) and B<done> (request has reached the end of its lifetime and
561	holds no resources anymore).
562
563	=over 4	755	=over 4
564		756
565	=item $req->cancel	757	=item cancel $req
566		758
567	Cancels the request, if possible. Has the effect of skipping execution	759	Cancels the request, if possible. Has the effect of skipping execution
568	when entering the B<execute> state and skipping calling the callback when	760	when entering the B<execute> state and skipping calling the callback when
569	entering the the B<result> state, but will leave the request otherwise	761	entering the the B<result> state, but will leave the request otherwise
570	untouched. That means that requests that currently execute will not be	762	untouched. That means that requests that currently execute will not be
571	stopped and resources held by the request will not be freed prematurely.	763	stopped and resources held by the request will not be freed prematurely.
572		764
		765	=item cb $req $callback->(...)
		766
		767	Replace (or simply set) the callback registered to the request.
		768
573	=back	769	=back
574		770
575	=head2 IO::AIO::GRP CLASS	771	=head2 IO::AIO::GRP CLASS
576		772
577	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to	773	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to
…		…
603	};	799	};
604		800
605	This makes it very easy to create composite requests (see the source of	801	This makes it very easy to create composite requests (see the source of
606	C<aio_move> for an application) that work and feel like simple requests.	802	C<aio_move> for an application) that work and feel like simple requests.
607		803
		804	=over 4
		805
608	The IO::AIO::GRP objects will be cleaned up during calls to	806	=item * The IO::AIO::GRP objects will be cleaned up during calls to
609	C<IO::AIO::poll_cb>, just like any other request.	807	C<IO::AIO::poll_cb>, just like any other request.
610		808
611	They can be canceled like any other request. Canceling will cancel not	809	=item * They can be canceled like any other request. Canceling will cancel not
612	only the request itself, but also all requests it contains.	810	only the request itself, but also all requests it contains.
613		811
614	They can also can also be added to other IO::AIO::GRP objects.	812	=item * They can also can also be added to other IO::AIO::GRP objects.
615		813
616	You must not add requests to a group from within the group callback (or	814	=item * You must not add requests to a group from within the group callback (or
617	any later time).	815	any later time).
		816
		817	=back
618		818
619	Their lifetime, simplified, looks like this: when they are empty, they	819	Their lifetime, simplified, looks like this: when they are empty, they
620	will finish very quickly. If they contain only requests that are in the	820	will finish very quickly. If they contain only requests that are in the
621	C<done> state, they will also finish. Otherwise they will continue to	821	C<done> state, they will also finish. Otherwise they will continue to
622	exist.	822	exist.
…		…
626	group. And only when all those requests have finished will the the group	826	group. And only when all those requests have finished will the the group
627	itself finish.	827	itself finish.
628		828
629	=over 4	829	=over 4
630		830
		831	=item add $grp ...
		832
631	=item $grp->add (...)	833	=item $grp->add (...)
632
633	=item add $grp ...
634		834
635	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can	835	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
636	be added, including other groups, as long as you do not create circular	836	be added, including other groups, as long as you do not create circular
637	dependencies.	837	dependencies.
638		838
639	Returns all its arguments.	839	Returns all its arguments.
640		840
		841	=item $grp->cancel_subs
		842
		843	Cancel all subrequests and clears any feeder, but not the group request
		844	itself. Useful when you queued a lot of events but got a result early.
		845
641	=item $grp->result (...)	846	=item $grp->result (...)
642		847
643	Set the result value(s) that will be passed to the group callback when all	848	Set the result value(s) that will be passed to the group callback when all
644	subrequests have finished. By default, no argument will be passed.	849	subrequests have finished and set thre groups errno to the current value
		850	of errno (just like calling C<errno> without an error number). By default,
		851	no argument will be passed and errno is zero.
645		852
646	=item $grp->set_feeder ($callback->($grp))	853	=item $grp->errno ([$errno])
647		854
648	[VERY EXPERIMENTAL]	855	Sets the group errno value to C<$errno>, or the current value of errno
		856	when the argument is missing.
		857
		858	Every aio request has an associated errno value that is restored when
		859	the callback is invoked. This method lets you change this value from its
		860	default (0).
		861
		862	Calling C<result> will also set errno, so make sure you either set C<$!>
		863	before the call to C<result>, or call c<errno> after it.
		864
		865	=item feed $grp $callback->($grp)
649		866
650	Sets a feeder/generator on this group: every group can have an attached	867	Sets a feeder/generator on this group: every group can have an attached
651	generator that generates requests if idle. The idea behind this is that,	868	generator that generates requests if idle. The idea behind this is that,
652	although you could just queue as many requests as you want in a group,	869	although you could just queue as many requests as you want in a group,
653	this might starve other requests for a potentially long time. For	870	this might starve other requests for a potentially long time. For
654	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	871	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
655	requests, delaying any later requests for a long time.	872	requests, delaying any later requests for a long time.
656		873
657	To avoid this, and allow incremental generation of requests, you can	874	To avoid this, and allow incremental generation of requests, you can
658	instead a group and set a feeder on it that generates those requests. The	875	instead a group and set a feeder on it that generates those requests. The
659	feeder will be called whenever there are few enough (see C<feeder_limit>,	876	feed callback will be called whenever there are few enough (see C<limit>,
660	below) requests active in the group itself and is expected to queue more	877	below) requests active in the group itself and is expected to queue more
661	requests.	878	requests.
662		879
663	The feeder can queue as many requests as it likes (i.e. C<add> does not	880	The feed callback can queue as many requests as it likes (i.e. C<add> does
664	impose any limits).	881	not impose any limits).
665		882
666	If the feeder does not queue more requests when called, it will be	883	If the feed does not queue more requests when called, it will be
667	automatically removed from the group.	884	automatically removed from the group.
668		885
669	If the feeder limit is C<0>, it will be set to C<2> automatically.	886	If the feed limit is C<0>, it will be set to C<2> automatically.
670		887
671	Example:	888	Example:
672		889
673	# stat all files in @files, but only ever use four aio requests concurrently:	890	# stat all files in @files, but only ever use four aio requests concurrently:
674		891
675	my $grp = aio_group sub { print "finished\n" };	892	my $grp = aio_group sub { print "finished\n" };
676	$grp->feeder_limit (4);	893	limit $grp 4;
677	$grp->set_feeder (sub {	894	feed $grp sub {
678	my $file = pop @files	895	my $file = pop @files
679	or return;	896	or return;
680		897
681	add $grp aio_stat $file, sub { ... };	898	add $grp aio_stat $file, sub { ... };
682	});	899	};
683		900
684	=item $grp->feeder_limit ($num)	901	=item limit $grp $num
685		902
686	Sets the feeder limit for the group: The feeder will be called whenever	903	Sets the feeder limit for the group: The feeder will be called whenever
687	the group contains less than this many requests.	904	the group contains less than this many requests.
688		905
689	Setting the limit to C<0> will pause the feeding process.	906	Setting the limit to C<0> will pause the feeding process.
690		907
691	=back	908	=back
692		909
693	=head2 SUPPORT FUNCTIONS	910	=head2 SUPPORT FUNCTIONS
		911
		912	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
694		913
695	=over 4	914	=over 4
696		915
697	=item $fileno = IO::AIO::poll_fileno	916	=item $fileno = IO::AIO::poll_fileno
698		917
…		…
703		922
704	See C<poll_cb> for an example.	923	See C<poll_cb> for an example.
705		924
706	=item IO::AIO::poll_cb	925	=item IO::AIO::poll_cb
707		926
708	Process all outstanding events on the result pipe. You have to call this	927	Process some outstanding events on the result pipe. You have to call this
709	regularly. Returns the number of events processed. Returns immediately	928	regularly. Returns the number of events processed. Returns immediately
710	when no events are outstanding.	929	when no events are outstanding. The amount of events processed depends on
		930	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		931
		932	If not all requests were processed for whatever reason, the filehandle
		933	will still be ready when C<poll_cb> returns.
711		934
712	Example: Install an Event watcher that automatically calls	935	Example: Install an Event watcher that automatically calls
713	IO::AIO::poll_cb with high priority:	936	IO::AIO::poll_cb with high priority:
714		937
715	Event->io (fd => IO::AIO::poll_fileno,	938	Event->io (fd => IO::AIO::poll_fileno,
716	poll => 'r', async => 1,	939	poll => 'r', async => 1,
717	cb => \&IO::AIO::poll_cb);	940	cb => \&IO::AIO::poll_cb);
718		941
		942	=item IO::AIO::max_poll_reqs $nreqs
		943
		944	=item IO::AIO::max_poll_time $seconds
		945
		946	These set the maximum number of requests (default C<0>, meaning infinity)
		947	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		948	the maximum amount of time (default C<0>, meaning infinity) spent in
		949	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		950	of time C<poll_cb> is allowed to use).
		951
		952	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		953	syscall per request processed, which is not normally a problem unless your
		954	callbacks are really really fast or your OS is really really slow (I am
		955	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		956
		957	Setting these is useful if you want to ensure some level of
		958	interactiveness when perl is not fast enough to process all requests in
		959	time.
		960
		961	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
		962
		963	Example: Install an Event watcher that automatically calls
		964	IO::AIO::poll_cb with low priority, to ensure that other parts of the
		965	program get the CPU sometimes even under high AIO load.
		966
		967	# try not to spend much more than 0.1s in poll_cb
		968	IO::AIO::max_poll_time 0.1;
		969
		970	# use a low priority so other tasks have priority
		971	Event->io (fd => IO::AIO::poll_fileno,
		972	poll => 'r', nice => 1,
		973	cb => &IO::AIO::poll_cb);
		974
719	=item IO::AIO::poll_wait	975	=item IO::AIO::poll_wait
720		976
		977	If there are any outstanding requests and none of them in the result
721	Wait till the result filehandle becomes ready for reading (simply does a	978	phase, wait till the result filehandle becomes ready for reading (simply
722	C<select> on the filehandle. This is useful if you want to synchronously wait	979	does a C<select> on the filehandle. This is useful if you want to
723	for some requests to finish).	980	synchronously wait for some requests to finish).
724		981
725	See C<nreqs> for an example.	982	See C<nreqs> for an example.
726		983
		984	=item IO::AIO::poll
		985
		986	Waits until some requests have been handled.
		987
		988	Returns the number of requests processed, but is otherwise strictly
		989	equivalent to:
		990
		991	IO::AIO::poll_wait, IO::AIO::poll_cb
		992
727	=item IO::AIO::nreqs	993	=item IO::AIO::flush
728		994
729	Returns the number of requests currently outstanding (i.e. for which their	995	Wait till all outstanding AIO requests have been handled.
730	callback has not been invoked yet).
731		996
732	Example: wait till there are no outstanding requests anymore:	997	Strictly equivalent to:
733		998
734	IO::AIO::poll_wait, IO::AIO::poll_cb	999	IO::AIO::poll_wait, IO::AIO::poll_cb
735	while IO::AIO::nreqs;	1000	while IO::AIO::nreqs;
736		1001
737	=item IO::AIO::flush	1002	=head3 CONTROLLING THE NUMBER OF THREADS
738
739	Wait till all outstanding AIO requests have been handled.
740
741	Strictly equivalent to:
742
743	IO::AIO::poll_wait, IO::AIO::poll_cb
744	while IO::AIO::nreqs;
745
746	=item IO::AIO::poll
747
748	Waits until some requests have been handled.
749
750	Strictly equivalent to:
751
752	IO::AIO::poll_wait, IO::AIO::poll_cb
753	if IO::AIO::nreqs;
754		1003
755	=item IO::AIO::min_parallel $nthreads	1004	=item IO::AIO::min_parallel $nthreads
756		1005
757	Set the minimum number of AIO threads to C<$nthreads>. The current default	1006	Set the minimum number of AIO threads to C<$nthreads>. The current
758	is C<4>, which means four asynchronous operations can be done at one time	1007	default is C<8>, which means eight asynchronous operations can execute
759	(the number of outstanding operations, however, is unlimited).	1008	concurrently at any one time (the number of outstanding requests,
		1009	however, is unlimited).
760		1010
761	IO::AIO starts threads only on demand, when an AIO request is queued and	1011	IO::AIO starts threads only on demand, when an AIO request is queued and
762	no free thread exists.	1012	no free thread exists. Please note that queueing up a hundred requests can
		1013	create demand for a hundred threads, even if it turns out that everything
		1014	is in the cache and could have been processed faster by a single thread.
763		1015
764	It is recommended to keep the number of threads low, as some Linux	1016	It is recommended to keep the number of threads relatively low, as some
765	kernel versions will scale negatively with the number of threads (higher	1017	Linux kernel versions will scale negatively with the number of threads
766	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	1018	(higher parallelity => MUCH higher latency). With current Linux 2.6
767	threads should be fine.	1019	versions, 4-32 threads should be fine.
768		1020
769	Under most circumstances you don't need to call this function, as the	1021	Under most circumstances you don't need to call this function, as the
770	module selects a default that is suitable for low to moderate load.	1022	module selects a default that is suitable for low to moderate load.
771		1023
772	=item IO::AIO::max_parallel $nthreads	1024	=item IO::AIO::max_parallel $nthreads
…		…
781	This module automatically runs C<max_parallel 0> at program end, to ensure	1033	This module automatically runs C<max_parallel 0> at program end, to ensure
782	that all threads are killed and that there are no outstanding requests.	1034	that all threads are killed and that there are no outstanding requests.
783		1035
784	Under normal circumstances you don't need to call this function.	1036	Under normal circumstances you don't need to call this function.
785		1037
		1038	=item IO::AIO::max_idle $nthreads
		1039
		1040	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1041	threads that did not get a request to process within 10 seconds). That
		1042	means if a thread becomes idle while C<$nthreads> other threads are also
		1043	idle, it will free its resources and exit.
		1044
		1045	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1046	to allow for extremely high load situations, but want to free resources
		1047	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1048
		1049	The default is probably ok in most situations, especially if thread
		1050	creation is fast. If thread creation is very slow on your system you might
		1051	want to use larger values.
		1052
786	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1053	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
		1054
		1055	This is a very bad function to use in interactive programs because it
		1056	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1057	use an C<aio_group> together with a feed callback.
787		1058
788	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1059	Sets the maximum number of outstanding requests to C<$nreqs>. If you
789	try to queue up more than this number of requests, the caller will block until	1060	to queue up more than this number of requests, the next call to the
790	some requests have been handled.	1061	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1062	function will block until the limit is no longer exceeded.
791		1063
792	The default is very large, so normally there is no practical limit. If you	1064	The default value is very large, so there is no practical limit on the
793	queue up many requests in a loop it often improves speed if you set	1065	number of outstanding requests.
794	this to a relatively low number, such as C<100>.
795		1066
796	Under normal circumstances you don't need to call this function.	1067	You can still queue as many requests as you want. Therefore,
		1068	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
		1069	as a stop gap to shield against fatal memory overflow (with large values).
		1070
		1071	=head3 STATISTICAL INFORMATION
		1072
		1073	=item IO::AIO::nreqs
		1074
		1075	Returns the number of requests currently in the ready, execute or pending
		1076	states (i.e. for which their callback has not been invoked yet).
		1077
		1078	Example: wait till there are no outstanding requests anymore:
		1079
		1080	IO::AIO::poll_wait, IO::AIO::poll_cb
		1081	while IO::AIO::nreqs;
		1082
		1083	=item IO::AIO::nready
		1084
		1085	Returns the number of requests currently in the ready state (not yet
		1086	executed).
		1087
		1088	=item IO::AIO::npending
		1089
		1090	Returns the number of requests currently in the pending state (executed,
		1091	but not yet processed by poll_cb).
797		1092
798	=back	1093	=back
799		1094
800	=cut	1095	=cut
801		1096
…		…
813	or return undef;	1108	or return undef;
814		1109
815	*$sym	1110	*$sym
816	}	1111	}
817		1112
818	min_parallel 4;	1113	min_parallel 8;
819		1114
820	END {	1115	END {
821	max_parallel 0;	1116	min_parallel 1;
822	}	1117	flush;
		1118	};
823		1119
824	1;	1120	1;
825		1121
826	=head2 FORK BEHAVIOUR	1122	=head2 FORK BEHAVIOUR
827		1123
828	This module should do "the right thing" when the process using it forks:	1124	This module should do "the right thing" when the process using it forks:
829		1125
830	Before the fork, IO::AIO enters a quiescent state where no requests	1126	Before the fork, IO::AIO enters a quiescent state where no requests
831	can be added in other threads and no results will be processed. After	1127	can be added in other threads and no results will be processed. After
832	the fork the parent simply leaves the quiescent state and continues	1128	the fork the parent simply leaves the quiescent state and continues
833	request/result processing, while the child clears the request/result	1129	request/result processing, while the child frees the request/result queue
834	queue (so the requests started before the fork will only be handled in	1130	(so that the requests started before the fork will only be handled in the
835	the parent). Threads will be started on demand until the limit ste in the	1131	parent). Threads will be started on demand until the limit set in the
836	parent process has been reached again.	1132	parent process has been reached again.
837		1133
838	In short: the parent will, after a short pause, continue as if fork had	1134	In short: the parent will, after a short pause, continue as if fork had
839	not been called, while the child will act as if IO::AIO has not been used	1135	not been called, while the child will act as if IO::AIO has not been used
840	yet.	1136	yet.
841		1137
842	=head2 MEMORY USAGE	1138	=head2 MEMORY USAGE
843		1139
		1140	Per-request usage:
		1141
844	Each aio request uses - depending on your architecture - around 128 bytes	1142	Each aio request uses - depending on your architecture - around 100-200
845	of memory. In addition, stat requests need a stat buffer (possibly a few	1143	bytes of memory. In addition, stat requests need a stat buffer (possibly
846	hundred bytes). Perl scalars and other data passed into aio requests will	1144	a few hundred bytes), readdir requires a result buffer and so on. Perl
847	also be locked.	1145	scalars and other data passed into aio requests will also be locked and
		1146	will consume memory till the request has entered the done state.
848		1147
849	This is now awfully much, so queuing lots of requests is not usually a	1148	This is now awfully much, so queuing lots of requests is not usually a
850	problem.	1149	problem.
851		1150
852	Each thread needs a stack area which is usually around 16k, sometimes much	1151	Per-thread usage:
853	larger, depending on the OS.	1152
		1153	In the execution phase, some aio requests require more memory for
		1154	temporary buffers, and each thread requires a stack and other data
		1155	structures (usually around 16k-128k, depending on the OS).
		1156
		1157	=head1 KNOWN BUGS
		1158
		1159	Known bugs will be fixed in the next release.
854		1160
855	=head1 SEE ALSO	1161	=head1 SEE ALSO
856		1162
857	L<Coro>, L<Linux::AIO> (obsolete).	1163	L<Coro::AIO>.
858		1164
859	=head1 AUTHOR	1165	=head1 AUTHOR
860		1166
861	Marc Lehmann <schmorp@schmorp.de>	1167	Marc Lehmann <schmorp@schmorp.de>
862	http://home.schmorp.de/	1168	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.60 by root, Sun Oct 22 13:33:28 2006 UTC vs. Revision 1.94 by root, Wed Nov 8 02:01:02 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.60 by root, Sun Oct 22 13:33:28 2006 UTC vs.
Revision 1.94 by root, Wed Nov 8 02:01:02 2006 UTC