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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC vs.
Revision 1.102 by root, Mon Jan 8 20:45:04 2007 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
…		…
51	=head1 DESCRIPTION	52	=head1 DESCRIPTION
52		53
53	This module implements asynchronous I/O using whatever means your	54	This module implements asynchronous I/O using whatever means your
54	operating system supports.	55	operating system supports.
55		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
56	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
57	and signal their completion. You don't need thread support in perl, and	75	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	76	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	77	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	78	functions available on many operating systems. However, they are often
61	(Linux doesn't allow them on normal files currently, for example),	79	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	and they would only support aio_read and aio_write, so the remaining	80	files currently, for example), and they would only support aio_read and
63	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.
64		83
65	Although the module will work with in the presence of other threads,	84	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	85	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	86	locking yourself, always call C<poll_cb> from within the same thread, or
68	call C<poll_cb> (or other 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
69		184
70	=cut	185	=cut
71		186
72	package IO::AIO;	187	package IO::AIO;
73		188
…		…
75	use strict 'vars';	190	use strict 'vars';
76		191
77	use base 'Exporter';	192	use base 'Exporter';
78		193
79	BEGIN {	194	BEGIN {
80	our $VERSION = '2.0';	195	our $VERSION = '2.32';
81		196
82	our @AIO_REQ = 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
83	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
84	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
85	aio_group aio_nop);	200	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir);
86	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
87	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
88	min_parallel max_parallel max_outstanding nreqs);	203	min_parallel max_parallel max_idle
		204	nreqs nready npending nthreads
		205	max_poll_time max_poll_reqs);
89		206
90	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
91		208
92	require XSLoader;	209	require XSLoader;
93	XSLoader::load ("IO::AIO", $VERSION);	210	XSLoader::load ("IO::AIO", $VERSION);
94	}	211	}
95		212
96	=head1 FUNCTIONS	213	=head1 FUNCTIONS
97		214
98	=head2 AIO FUNCTIONS	215	=head2 AIO REQUEST FUNCTIONS
99		216
100	All the C<aio_*> calls are more or less thin wrappers around the syscall	217	All the C<aio_*> calls are more or less thin wrappers around the syscall
101	with the same name (sans C<aio_>). The arguments are similar or identical,	218	with the same name (sans C<aio_>). The arguments are similar or identical,
102	and they all accept an additional (and optional) C<$callback> argument	219	and they all accept an additional (and optional) C<$callback> argument
103	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
…		…
106	syscall has been executed asynchronously.	223	syscall has been executed asynchronously.
107		224
108	All functions expecting a filehandle keep a copy of the filehandle	225	All functions expecting a filehandle keep a copy of the filehandle
109	internally until the request has finished.	226	internally until the request has finished.
110		227
111	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
112	manipulation of those requests while they are in-flight.	229	further manipulation of those requests while they are in-flight.
113		230
114	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
115	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
116	request is being executed, the current working directory could have	233	request is being executed, the current working directory could have
117	changed. Alternatively, you can make sure that you never change the	234	changed. Alternatively, you can make sure that you never change the
118	current working directory.	235	current working directory anywhere in the program and then use relative
		236	paths.
119		237
120	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
121	always pass in filenames you got from outside (command line, readdir	239	in filenames you got from outside (command line, readdir etc.) without
122	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
123	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
124	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)
125	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.
126		247
127	=over 4	248	=over 4
128		249
129	=item aioreq_pri $pri	250	=item $prev_pri = aioreq_pri [$pri]
130		251
131	Sets the priority for the next aio request. The default priority	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
132	is C<0>, the minimum and maximum priorities are C<-4> and C<4>,	255	The default priority is C<0>, the minimum and maximum priorities are C<-4>
133	respectively. Requests with higher priority will be serviced first.	256	and C<4>, respectively. Requests with higher priority will be serviced
		257	first.
134		258
135	The priority will be reset to C<0> after each call to one of the C<aio_>	259	The priority will be reset to C<0> after each call to one of the C<aio_*>
136	functions.	260	functions.
137		261
138	Example: open a file with low priority, then read something from it with	262	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	263	higher priority so the read request is serviced before other low priority
140	open requests (potentially spamming the cache):	264	open requests (potentially spamming the cache):
…		…
150	};	274	};
151		275
152	=item aioreq_nice $pri_adjust	276	=item aioreq_nice $pri_adjust
153		277
154	Similar to C<aioreq_pri>, but subtracts the given value from the current	278	Similar to C<aioreq_pri>, but subtracts the given value from the current
155	priority, so effects are cumulative.	279	priority, so the effect is cumulative.
156		280
157	=item aio_open $pathname, $flags, $mode, $callback->($fh)	281	=item aio_open $pathname, $flags, $mode, $callback->($fh)
158		282
159	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
160	created filehandle for the file.	284	created filehandle for the file.
…		…
166	list. They are the same as used by C<sysopen>.	290	list. They are the same as used by C<sysopen>.
167		291
168	Likewise, C<$mode> specifies the mode of the newly created file, if it	292	Likewise, C<$mode> specifies the mode of the newly created file, if it
169	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	293	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
170	except that it is mandatory (i.e. use C<0> if you don't create new files,	294	except that it is mandatory (i.e. use C<0> if you don't create new files,
171	and C<0666> or C<0777> if you do).	295	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		296	by the umask in effect then the request is being executed, so better never
		297	change the umask.
172		298
173	Example:	299	Example:
174		300
175	aio_open "/etc/passwd", O_RDONLY, 0, sub {	301	aio_open "/etc/passwd", O_RDONLY, 0, sub {
176	if ($_[0]) {	302	if ($_[0]) {
…		…
211	aio_read $fh, 7, 15, $buffer, 0, sub {	337	aio_read $fh, 7, 15, $buffer, 0, sub {
212	$_[0] > 0 or die "read error: $!";	338	$_[0] > 0 or die "read error: $!";
213	print "read $_[0] bytes: <$buffer>\n";	339	print "read $_[0] bytes: <$buffer>\n";
214	};	340	};
215		341
216	=item aio_move $srcpath, $dstpath, $callback->($status)
217
218	[EXPERIMENTAL due to internal aio_group use]
219
220	Try to move the I<file> (directories not supported as either source or
221	destination) from C<$srcpath> to C<$dstpath> and call the callback with
222	the C<0> (error) or C<-1> ok.
223
224	This is a composite request that tries to rename(2) the file first. If
225	rename files with C<EXDEV>, it creates the destination file with mode 0200
226	and copies the contents of the source file into it using C<aio_sendfile>,
227	followed by restoring atime, mtime, access mode and uid/gid, in that
228	order, and unlinking the C<$srcpath>.
229
230	If an error occurs, the partial destination file will be unlinked, if
231	possible, except when setting atime, mtime, access mode and uid/gid, where
232	errors are being ignored.
233
234	=cut
235
236	sub aio_move($$$) {
237	my ($src, $dst, $cb) = @_;
238
239	my $grp = aio_group $cb;
240
241	add $grp aio_rename $src, $dst, sub {
242	if ($_[0] && $! == EXDEV) {
243	add $grp aio_open $src, O_RDONLY, 0, sub {
244	if (my $src_fh = $_[0]) {
245	my @stat = stat $src_fh;
246
247	add $grp aio_open $dst, O_WRONLY, 0200, sub {
248	if (my $dst_fh = $_[0]) {
249	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
250	close $src_fh;
251
252	if ($_[0] == $stat[7]) {
253	utime $stat[8], $stat[9], $dst;
254	chmod $stat[2] & 07777, $dst_fh;
255	chown $stat[4], $stat[5], $dst_fh;
256	close $dst_fh;
257
258	add $grp aio_unlink $src, sub {
259	$grp->result ($_[0]);
260	};
261	} else {
262	my $errno = $!;
263	add $grp aio_unlink $dst, sub {
264	$! = $errno;
265	$grp->result (-1);
266	};
267	}
268	};
269	} else {
270	$grp->result (-1);
271	}
272	},
273
274	} else {
275	$grp->result (-1);
276	}
277	};
278	} else {
279	$grp->result ($_[0]);
280	}
281	};
282
283	$grp
284	}
285
286	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	342	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
287		343
288	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	344	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
289	reading at byte offset C<$in_offset>, and starts writing at the current	345	reading at byte offset C<$in_offset>, and starts writing at the current
290	file offset of C<$out_fh>. Because of that, it is not safe to issue more	346	file offset of C<$out_fh>. Because of that, it is not safe to issue more
…		…
345	=item aio_unlink $pathname, $callback->($status)	401	=item aio_unlink $pathname, $callback->($status)
346		402
347	Asynchronously unlink (delete) a file and call the callback with the	403	Asynchronously unlink (delete) a file and call the callback with the
348	result code.	404	result code.
349		405
		406	=item aio_mknod $path, $mode, $dev, $callback->($status)
		407
		408	[EXPERIMENTAL]
		409
		410	Asynchronously create a device node (or fifo). See mknod(2).
		411
		412	The only (POSIX-) portable way of calling this function is:
		413
		414	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		415
350	=item aio_link $srcpath, $dstpath, $callback->($status)	416	=item aio_link $srcpath, $dstpath, $callback->($status)
351		417
352	Asynchronously create a new link to the existing object at C<$srcpath> at	418	Asynchronously create a new link to the existing object at C<$srcpath> at
353	the path C<$dstpath> and call the callback with the result code.	419	the path C<$dstpath> and call the callback with the result code.
354		420
355	=item aio_symlink $srcpath, $dstpath, $callback->($status)	421	=item aio_symlink $srcpath, $dstpath, $callback->($status)
356		422
357	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	423	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
358	the path C<$dstpath> and call the callback with the result code.	424	the path C<$dstpath> and call the callback with the result code.
359		425
		426	=item aio_readlink $path, $callback->($link)
		427
		428	Asynchronously read the symlink specified by C<$path> and pass it to
		429	the callback. If an error occurs, nothing or undef gets passed to the
		430	callback.
		431
360	=item aio_rename $srcpath, $dstpath, $callback->($status)	432	=item aio_rename $srcpath, $dstpath, $callback->($status)
361		433
362	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	434	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
363	rename(2) and call the callback with the result code.	435	rename(2) and call the callback with the result code.
		436
		437	=item aio_mkdir $pathname, $mode, $callback->($status)
		438
		439	Asynchronously mkdir (create) a directory and call the callback with
		440	the result code. C<$mode> will be modified by the umask at the time the
		441	request is executed, so do not change your umask.
364		442
365	=item aio_rmdir $pathname, $callback->($status)	443	=item aio_rmdir $pathname, $callback->($status)
366		444
367	Asynchronously rmdir (delete) a directory and call the callback with the	445	Asynchronously rmdir (delete) a directory and call the callback with the
368	result code.	446	result code.
…		…
374	sorted, and will B<NOT> include the C<.> and C<..> entries.	452	sorted, and will B<NOT> include the C<.> and C<..> entries.
375		453
376	The callback a single argument which is either C<undef> or an array-ref	454	The callback a single argument which is either C<undef> or an array-ref
377	with the filenames.	455	with the filenames.
378		456
		457	=item aio_load $path, $data, $callback->($status)
		458
		459	This is a composite request that tries to fully load the given file into
		460	memory. Status is the same as with aio_read.
		461
		462	=cut
		463
		464	sub aio_load($$;$) {
		465	aio_block {
		466	my ($path, undef, $cb) = @_;
		467	my $data = \$_[1];
		468
		469	my $pri = aioreq_pri;
		470	my $grp = aio_group $cb;
		471
		472	aioreq_pri $pri;
		473	add $grp aio_open $path, O_RDONLY, 0, sub {
		474	my $fh = shift
		475	or return $grp->result (-1);
		476
		477	aioreq_pri $pri;
		478	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		479	$grp->result ($_[0]);
		480	};
		481	};
		482
		483	$grp
		484	}
		485	}
		486
		487	=item aio_copy $srcpath, $dstpath, $callback->($status)
		488
		489	Try to copy the I<file> (directories not supported as either source or
		490	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		491	the C<0> (error) or C<-1> ok.
		492
		493	This is a composite request that it creates the destination file with
		494	mode 0200 and copies the contents of the source file into it using
		495	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		496	uid/gid, in that order.
		497
		498	If an error occurs, the partial destination file will be unlinked, if
		499	possible, except when setting atime, mtime, access mode and uid/gid, where
		500	errors are being ignored.
		501
		502	=cut
		503
		504	sub aio_copy($$;$) {
		505	aio_block {
		506	my ($src, $dst, $cb) = @_;
		507
		508	my $pri = aioreq_pri;
		509	my $grp = aio_group $cb;
		510
		511	aioreq_pri $pri;
		512	add $grp aio_open $src, O_RDONLY, 0, sub {
		513	if (my $src_fh = $_[0]) {
		514	my @stat = stat $src_fh;
		515
		516	aioreq_pri $pri;
		517	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		518	if (my $dst_fh = $_[0]) {
		519	aioreq_pri $pri;
		520	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		521	if ($_[0] == $stat[7]) {
		522	$grp->result (0);
		523	close $src_fh;
		524
		525	# those should not normally block. should. should.
		526	utime $stat[8], $stat[9], $dst;
		527	chmod $stat[2] & 07777, $dst_fh;
		528	chown $stat[4], $stat[5], $dst_fh;
		529	close $dst_fh;
		530	} else {
		531	$grp->result (-1);
		532	close $src_fh;
		533	close $dst_fh;
		534
		535	aioreq $pri;
		536	add $grp aio_unlink $dst;
		537	}
		538	};
		539	} else {
		540	$grp->result (-1);
		541	}
		542	},
		543
		544	} else {
		545	$grp->result (-1);
		546	}
		547	};
		548
		549	$grp
		550	}
		551	}
		552
		553	=item aio_move $srcpath, $dstpath, $callback->($status)
		554
		555	Try to move the I<file> (directories not supported as either source or
		556	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		557	the C<0> (error) or C<-1> ok.
		558
		559	This is a composite request that tries to rename(2) the file first. If
		560	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		561	that is successful, unlinking the C<$srcpath>.
		562
		563	=cut
		564
		565	sub aio_move($$;$) {
		566	aio_block {
		567	my ($src, $dst, $cb) = @_;
		568
		569	my $pri = aioreq_pri;
		570	my $grp = aio_group $cb;
		571
		572	aioreq_pri $pri;
		573	add $grp aio_rename $src, $dst, sub {
		574	if ($_[0] && $! == EXDEV) {
		575	aioreq_pri $pri;
		576	add $grp aio_copy $src, $dst, sub {
		577	$grp->result ($_[0]);
		578
		579	if (!$_[0]) {
		580	aioreq_pri $pri;
		581	add $grp aio_unlink $src;
		582	}
		583	};
		584	} else {
		585	$grp->result ($_[0]);
		586	}
		587	};
		588
		589	$grp
		590	}
		591	}
		592
379	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	593	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
380		594
381	[EXPERIMENTAL due to internal aio_group use]
382
383	Scans a directory (similar to C<aio_readdir>) but additionally tries to	595	Scans a directory (similar to C<aio_readdir>) but additionally tries to
384	separate the entries of directory C<$path> into two sets of names, ones	596	efficiently separate the entries of directory C<$path> into two sets of
385	you can recurse into (directories or links to them), and ones you cannot	597	names, directories you can recurse into (directories), and ones you cannot
386	recurse into (everything else).	598	recurse into (everything else, including symlinks to directories).
387		599
388	C<aio_scandir> is a composite request that creates of many sub requests_	600	C<aio_scandir> is a composite request that creates of many sub requests_
389	C<$maxreq> specifies the maximum number of outstanding aio requests that	601	C<$maxreq> specifies the maximum number of outstanding aio requests that
390	this function generates. If it is C<< <= 0 >>, then a suitable default	602	this function generates. If it is C<< <= 0 >>, then a suitable default
391	will be chosen (currently 6).	603	will be chosen (currently 4).
392		604
393	On error, the callback is called without arguments, otherwise it receives	605	On error, the callback is called without arguments, otherwise it receives
394	two array-refs with path-relative entry names.	606	two array-refs with path-relative entry names.
395		607
396	Example:	608	Example:
…		…
430	as those tend to return 0 or 1 as link counts, which disables the	642	as those tend to return 0 or 1 as link counts, which disables the
431	directory counting heuristic.	643	directory counting heuristic.
432		644
433	=cut	645	=cut
434		646
435	sub aio_scandir($$$) {	647	sub aio_scandir($$;$) {
		648	aio_block {
436	my ($path, $maxreq, $cb) = @_;	649	my ($path, $maxreq, $cb) = @_;
437		650
		651	my $pri = aioreq_pri;
		652
438	my $grp = aio_group $cb;	653	my $grp = aio_group $cb;
439		654
440	$maxreq = 6 if $maxreq <= 0;	655	$maxreq = 4 if $maxreq <= 0;
441		656
442	# stat once	657	# stat once
		658	aioreq_pri $pri;
443	add $grp aio_stat $path, sub {	659	add $grp aio_stat $path, sub {
444	return $grp->result () if $_[0];	660	return $grp->result () if $_[0];
445	my $now = time;	661	my $now = time;
446	my $hash1 = join ":", (stat _)[0,1,3,7,9];	662	my $hash1 = join ":", (stat _)[0,1,3,7,9];
447		663
448	# read the directory entries	664	# read the directory entries
		665	aioreq_pri $pri;
449	add $grp aio_readdir $path, sub {	666	add $grp aio_readdir $path, sub {
450	my $entries = shift	667	my $entries = shift
451	or return $grp->result ();	668	or return $grp->result ();
452		669
453	# stat the dir another time	670	# stat the dir another time
		671	aioreq_pri $pri;
454	add $grp aio_stat $path, sub {	672	add $grp aio_stat $path, sub {
455	my $hash2 = join ":", (stat _)[0,1,3,7,9];	673	my $hash2 = join ":", (stat _)[0,1,3,7,9];
456		674
457	my $ndirs;	675	my $ndirs;
458		676
459	# take the slow route if anything looks fishy	677	# take the slow route if anything looks fishy
460	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	678	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
461	$ndirs = -1;	679	$ndirs = -1;
462	} else {	680	} else {
463	# if nlink == 2, we are finished	681	# if nlink == 2, we are finished
464	# on non-posix-fs's, we rely on nlink < 2	682	# on non-posix-fs's, we rely on nlink < 2
465	$ndirs = (stat _)[3] - 2	683	$ndirs = (stat _)[3] - 2
466	or return $grp->result ([], $entries);	684	or return $grp->result ([], $entries);
467	}	685	}
468		686
469	# sort into likely dirs and likely nondirs	687	# sort into likely dirs and likely nondirs
470	# dirs == files without ".", short entries first	688	# dirs == files without ".", short entries first
471	$entries = [map $_->[0],	689	$entries = [map $_->[0],
472	sort { $b->[1] cmp $a->[1] }	690	sort { $b->[1] cmp $a->[1] }
473	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	691	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
474	@$entries];	692	@$entries];
475		693
476	my (@dirs, @nondirs);	694	my (@dirs, @nondirs);
477		695
478	my ($statcb, $schedcb);
479	my $nreq = 0;
480
481	my $statgrp = add $grp aio_group;	696	my $statgrp = add $grp aio_group sub {
482
483	$schedcb = sub {
484	if (@$entries) {
485	if ($nreq < $maxreq) {
486	my $ent = pop @$entries;
487	$nreq++;
488	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
489	}
490	} elsif (!$nreq) {
491	# finished
492	$statgrp->cancel;
493	undef $statcb;
494	undef $schedcb;
495	$grp->result (\@dirs, \@nondirs);	697	$grp->result (\@dirs, \@nondirs);
496	}	698	};
		699
		700	limit $statgrp $maxreq;
		701	feed $statgrp sub {
		702	return unless @$entries;
		703	my $entry = pop @$entries;
		704
		705	aioreq_pri $pri;
		706	add $statgrp aio_stat "$path/$entry/.", sub {
		707	if ($_[0] < 0) {
		708	push @nondirs, $entry;
		709	} else {
		710	# need to check for real directory
		711	aioreq_pri $pri;
		712	add $statgrp aio_lstat "$path/$entry", sub {
		713	if (-d _) {
		714	push @dirs, $entry;
		715
		716	unless (--$ndirs) {
		717	push @nondirs, @$entries;
		718	feed $statgrp;
		719	}
		720	} else {
		721	push @nondirs, $entry;
		722	}
		723	}
		724	}
		725	};
		726	};
497	};	727	};
498	$statcb = sub {
499	my ($status, $entry) = @_;
500
501	if ($status < 0) {
502	$nreq--;
503	push @nondirs, $entry;
504	&$schedcb;
505	} else {
506	# need to check for real directory
507	add $grp aio_lstat "$path/$entry", sub {
508	$nreq--;
509
510	if (-d _) {
511	push @dirs, $entry;
512
513	if (!--$ndirs) {
514	push @nondirs, @$entries;
515	$entries = [];
516	}
517	} else {
518	push @nondirs, $entry;
519	}
520
521	&$schedcb;
522	}
523	}
524	};
525
526	&$schedcb while @$entries && $nreq < $maxreq;
527	};	728	};
528	};	729	};
		730
		731	$grp
529	};	732	}
		733	}
530		734
		735	=item aio_rmtree $path, $callback->($status)
		736
		737	Delete a directory tree starting (and including) C<$path>, return the
		738	status of the final C<rmdir> only. This is a composite request that
		739	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		740	everything else.
		741
		742	=cut
		743
		744	sub aio_rmtree;
		745	sub aio_rmtree($;$) {
		746	aio_block {
		747	my ($path, $cb) = @_;
		748
		749	my $pri = aioreq_pri;
		750	my $grp = aio_group $cb;
		751
		752	aioreq_pri $pri;
		753	add $grp aio_scandir $path, 0, sub {
		754	my ($dirs, $nondirs) = @_;
		755
		756	my $dirgrp = aio_group sub {
		757	add $grp aio_rmdir $path, sub {
		758	$grp->result ($_[0]);
		759	};
		760	};
		761
		762	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		763	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		764
		765	add $grp $dirgrp;
		766	};
		767
531	$grp	768	$grp
		769	}
532	}	770	}
533		771
534	=item aio_fsync $fh, $callback->($status)	772	=item aio_fsync $fh, $callback->($status)
535		773
536	Asynchronously call fsync on the given filehandle and call the callback	774	Asynchronously call fsync on the given filehandle and call the callback
…		…
544	If this call isn't available because your OS lacks it or it couldn't be	782	If this call isn't available because your OS lacks it or it couldn't be
545	detected, it will be emulated by calling C<fsync> instead.	783	detected, it will be emulated by calling C<fsync> instead.
546		784
547	=item aio_group $callback->(...)	785	=item aio_group $callback->(...)
548		786
549	[EXPERIMENTAL]
550
551	This is a very special aio request: Instead of doing something, it is a	787	This is a very special aio request: Instead of doing something, it is a
552	container for other aio requests, which is useful if you want to bundle	788	container for other aio requests, which is useful if you want to bundle
553	many requests into a single, composite, request.	789	many requests into a single, composite, request with a definite callback
		790	and the ability to cancel the whole request with its subrequests.
554		791
555	Returns an object of class L<IO::AIO::GRP>. See its documentation below	792	Returns an object of class L<IO::AIO::GRP>. See its documentation below
556	for more info.	793	for more info.
557		794
558	Example:	795	Example:
…		…
577	phase and still requires a worker thread. Thus, the callback will not	814	phase and still requires a worker thread. Thus, the callback will not
578	be executed immediately but only after other requests in the queue have	815	be executed immediately but only after other requests in the queue have
579	entered their execution phase. This can be used to measure request	816	entered their execution phase. This can be used to measure request
580	latency.	817	latency.
581		818
582	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	819	=item IO::AIO::aio_busy $fractional_seconds, $callback->() NOT EXPORTED
583		820
584	Mainly used for debugging and benchmarking, this aio request puts one of	821	Mainly used for debugging and benchmarking, this aio request puts one of
585	the request workers to sleep for the given time.	822	the request workers to sleep for the given time.
586		823
587	While it is theoretically handy to have simple I/O scheduling requests	824	While it is theoretically handy to have simple I/O scheduling requests
588	like sleep and file handle readable/writable, the overhead this creates	825	like sleep and file handle readable/writable, the overhead this creates is
589	is immense, so do not use this function except to put your application	826	immense (it blocks a thread for a long time) so do not use this function
590	under artificial I/O pressure.	827	except to put your application under artificial I/O pressure.
591		828
592	=back	829	=back
593		830
594	=head2 IO::AIO::REQ CLASS	831	=head2 IO::AIO::REQ CLASS
595		832
596	All non-aggregate C<aio_*> functions return an object of this class when	833	All non-aggregate C<aio_*> functions return an object of this class when
597	called in non-void context.	834	called in non-void context.
598
599	A request always moves through the following five states in its lifetime,
600	in order: B<ready> (request has been created, but has not been executed
601	yet), B<execute> (request is currently being executed), B<pending>
602	(request has been executed but callback has not been called yet),
603	B<result> (results are being processed synchronously, includes calling the
604	callback) and B<done> (request has reached the end of its lifetime and
605	holds no resources anymore).
606		835
607	=over 4	836	=over 4
608		837
609	=item cancel $req	838	=item cancel $req
610		839
…		…
664	=item * They can also can also be added to other IO::AIO::GRP objects.	893	=item * They can also can also be added to other IO::AIO::GRP objects.
665		894
666	=item * You must not add requests to a group from within the group callback (or	895	=item * You must not add requests to a group from within the group callback (or
667	any later time).	896	any later time).
668		897
669	=item * This does not harmonise well with C<max_outstanding>, so best do
670	not combine C<aio_group> with it. Groups and feeders are recommended for
671	this kind of concurrency-limiting.
672
673	=back	898	=back
674		899
675	Their lifetime, simplified, looks like this: when they are empty, they	900	Their lifetime, simplified, looks like this: when they are empty, they
676	will finish very quickly. If they contain only requests that are in the	901	will finish very quickly. If they contain only requests that are in the
677	C<done> state, they will also finish. Otherwise they will continue to	902	C<done> state, they will also finish. Otherwise they will continue to
…		…
692	be added, including other groups, as long as you do not create circular	917	be added, including other groups, as long as you do not create circular
693	dependencies.	918	dependencies.
694		919
695	Returns all its arguments.	920	Returns all its arguments.
696		921
		922	=item $grp->cancel_subs
		923
		924	Cancel all subrequests and clears any feeder, but not the group request
		925	itself. Useful when you queued a lot of events but got a result early.
		926
697	=item $grp->result (...)	927	=item $grp->result (...)
698		928
699	Set the result value(s) that will be passed to the group callback when all	929	Set the result value(s) that will be passed to the group callback when all
700	subrequests have finished. By default, no argument will be passed.	930	subrequests have finished and set thre groups errno to the current value
		931	of errno (just like calling C<errno> without an error number). By default,
		932	no argument will be passed and errno is zero.
		933
		934	=item $grp->errno ([$errno])
		935
		936	Sets the group errno value to C<$errno>, or the current value of errno
		937	when the argument is missing.
		938
		939	Every aio request has an associated errno value that is restored when
		940	the callback is invoked. This method lets you change this value from its
		941	default (0).
		942
		943	Calling C<result> will also set errno, so make sure you either set C<$!>
		944	before the call to C<result>, or call c<errno> after it.
701		945
702	=item feed $grp $callback->($grp)	946	=item feed $grp $callback->($grp)
703
704	[VERY EXPERIMENTAL]
705		947
706	Sets a feeder/generator on this group: every group can have an attached	948	Sets a feeder/generator on this group: every group can have an attached
707	generator that generates requests if idle. The idea behind this is that,	949	generator that generates requests if idle. The idea behind this is that,
708	although you could just queue as many requests as you want in a group,	950	although you could just queue as many requests as you want in a group,
709	this might starve other requests for a potentially long time. For	951	this might starve other requests for a potentially long time. For
…		…
746		988
747	=back	989	=back
748		990
749	=head2 SUPPORT FUNCTIONS	991	=head2 SUPPORT FUNCTIONS
750		992
		993	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		994
751	=over 4	995	=over 4
752		996
753	=item $fileno = IO::AIO::poll_fileno	997	=item $fileno = IO::AIO::poll_fileno
754		998
755	Return the I<request result pipe file descriptor>. This filehandle must be	999	Return the I<request result pipe file descriptor>. This filehandle must be
…		…
759		1003
760	See C<poll_cb> for an example.	1004	See C<poll_cb> for an example.
761		1005
762	=item IO::AIO::poll_cb	1006	=item IO::AIO::poll_cb
763		1007
764	Process all outstanding events on the result pipe. You have to call this	1008	Process some outstanding events on the result pipe. You have to call this
765	regularly. Returns the number of events processed. Returns immediately	1009	regularly. Returns the number of events processed. Returns immediately
766	when no events are outstanding.	1010	when no events are outstanding. The amount of events processed depends on
		1011	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		1012
		1013	If not all requests were processed for whatever reason, the filehandle
		1014	will still be ready when C<poll_cb> returns.
767		1015
768	Example: Install an Event watcher that automatically calls	1016	Example: Install an Event watcher that automatically calls
769	IO::AIO::poll_cb with high priority:	1017	IO::AIO::poll_cb with high priority:
770		1018
771	Event->io (fd => IO::AIO::poll_fileno,	1019	Event->io (fd => IO::AIO::poll_fileno,
772	poll => 'r', async => 1,	1020	poll => 'r', async => 1,
773	cb => \&IO::AIO::poll_cb);	1021	cb => \&IO::AIO::poll_cb);
774		1022
		1023	=item IO::AIO::max_poll_reqs $nreqs
		1024
		1025	=item IO::AIO::max_poll_time $seconds
		1026
		1027	These set the maximum number of requests (default C<0>, meaning infinity)
		1028	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1029	the maximum amount of time (default C<0>, meaning infinity) spent in
		1030	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1031	of time C<poll_cb> is allowed to use).
		1032
		1033	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1034	syscall per request processed, which is not normally a problem unless your
		1035	callbacks are really really fast or your OS is really really slow (I am
		1036	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1037
		1038	Setting these is useful if you want to ensure some level of
		1039	interactiveness when perl is not fast enough to process all requests in
		1040	time.
		1041
		1042	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
		1043
		1044	Example: Install an Event watcher that automatically calls
		1045	IO::AIO::poll_cb with low priority, to ensure that other parts of the
		1046	program get the CPU sometimes even under high AIO load.
		1047
		1048	# try not to spend much more than 0.1s in poll_cb
		1049	IO::AIO::max_poll_time 0.1;
		1050
		1051	# use a low priority so other tasks have priority
		1052	Event->io (fd => IO::AIO::poll_fileno,
		1053	poll => 'r', nice => 1,
		1054	cb => &IO::AIO::poll_cb);
		1055
775	=item IO::AIO::poll_wait	1056	=item IO::AIO::poll_wait
776		1057
		1058	If there are any outstanding requests and none of them in the result
777	Wait till the result filehandle becomes ready for reading (simply does a	1059	phase, wait till the result filehandle becomes ready for reading (simply
778	C<select> on the filehandle. This is useful if you want to synchronously wait	1060	does a C<select> on the filehandle. This is useful if you want to
779	for some requests to finish).	1061	synchronously wait for some requests to finish).
780		1062
781	See C<nreqs> for an example.	1063	See C<nreqs> for an example.
782		1064
		1065	=item IO::AIO::poll
		1066
		1067	Waits until some requests have been handled.
		1068
		1069	Returns the number of requests processed, but is otherwise strictly
		1070	equivalent to:
		1071
		1072	IO::AIO::poll_wait, IO::AIO::poll_cb
		1073
783	=item IO::AIO::nreqs	1074	=item IO::AIO::flush
784		1075
785	Returns the number of requests currently outstanding (i.e. for which their	1076	Wait till all outstanding AIO requests have been handled.
786	callback has not been invoked yet).
787		1077
788	Example: wait till there are no outstanding requests anymore:	1078	Strictly equivalent to:
789		1079
790	IO::AIO::poll_wait, IO::AIO::poll_cb	1080	IO::AIO::poll_wait, IO::AIO::poll_cb
791	while IO::AIO::nreqs;	1081	while IO::AIO::nreqs;
792		1082
793	=item IO::AIO::flush	1083	=head3 CONTROLLING THE NUMBER OF THREADS
794
795	Wait till all outstanding AIO requests have been handled.
796
797	Strictly equivalent to:
798
799	IO::AIO::poll_wait, IO::AIO::poll_cb
800	while IO::AIO::nreqs;
801
802	=item IO::AIO::poll
803
804	Waits until some requests have been handled.
805
806	Strictly equivalent to:
807
808	IO::AIO::poll_wait, IO::AIO::poll_cb
809	if IO::AIO::nreqs;
810		1084
811	=item IO::AIO::min_parallel $nthreads	1085	=item IO::AIO::min_parallel $nthreads
812		1086
813	Set the minimum number of AIO threads to C<$nthreads>. The current	1087	Set the minimum number of AIO threads to C<$nthreads>. The current
814	default is C<8>, which means eight asynchronous operations can execute	1088	default is C<8>, which means eight asynchronous operations can execute
815	concurrently at any one time (the number of outstanding requests,	1089	concurrently at any one time (the number of outstanding requests,
816	however, is unlimited).	1090	however, is unlimited).
817		1091
818	IO::AIO starts threads only on demand, when an AIO request is queued and	1092	IO::AIO starts threads only on demand, when an AIO request is queued and
819	no free thread exists.	1093	no free thread exists. Please note that queueing up a hundred requests can
		1094	create demand for a hundred threads, even if it turns out that everything
		1095	is in the cache and could have been processed faster by a single thread.
820		1096
821	It is recommended to keep the number of threads relatively low, as some	1097	It is recommended to keep the number of threads relatively low, as some
822	Linux kernel versions will scale negatively with the number of threads	1098	Linux kernel versions will scale negatively with the number of threads
823	(higher parallelity => MUCH higher latency). With current Linux 2.6	1099	(higher parallelity => MUCH higher latency). With current Linux 2.6
824	versions, 4-32 threads should be fine.	1100	versions, 4-32 threads should be fine.
…		…
838	This module automatically runs C<max_parallel 0> at program end, to ensure	1114	This module automatically runs C<max_parallel 0> at program end, to ensure
839	that all threads are killed and that there are no outstanding requests.	1115	that all threads are killed and that there are no outstanding requests.
840		1116
841	Under normal circumstances you don't need to call this function.	1117	Under normal circumstances you don't need to call this function.
842		1118
		1119	=item IO::AIO::max_idle $nthreads
		1120
		1121	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1122	threads that did not get a request to process within 10 seconds). That
		1123	means if a thread becomes idle while C<$nthreads> other threads are also
		1124	idle, it will free its resources and exit.
		1125
		1126	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1127	to allow for extremely high load situations, but want to free resources
		1128	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1129
		1130	The default is probably ok in most situations, especially if thread
		1131	creation is fast. If thread creation is very slow on your system you might
		1132	want to use larger values.
		1133
843	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1134	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
844		1135
845	[DEPRECATED]	1136	This is a very bad function to use in interactive programs because it
		1137	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1138	use an C<aio_group> together with a feed callback.
846		1139
847	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1140	Sets the maximum number of outstanding requests to C<$nreqs>. If you
848	try to queue up more than this number of requests, the caller will block until	1141	to queue up more than this number of requests, the next call to the
849	some requests have been handled.	1142	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1143	function will block until the limit is no longer exceeded.
850		1144
851	The default is very large, so normally there is no practical limit. If you	1145	The default value is very large, so there is no practical limit on the
852	queue up many requests in a loop it often improves speed if you set	1146	number of outstanding requests.
853	this to a relatively low number, such as C<100>.
854		1147
855	This function does not work well together with C<aio_group>'s, and their	1148	You can still queue as many requests as you want. Therefore,
856	feeder interface is better suited to limiting concurrency, so do not use	1149	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
857	this function.	1150	as a stop gap to shield against fatal memory overflow (with large values).
858		1151
859	Under normal circumstances you don't need to call this function.	1152	=head3 STATISTICAL INFORMATION
		1153
		1154	=item IO::AIO::nreqs
		1155
		1156	Returns the number of requests currently in the ready, execute or pending
		1157	states (i.e. for which their callback has not been invoked yet).
		1158
		1159	Example: wait till there are no outstanding requests anymore:
		1160
		1161	IO::AIO::poll_wait, IO::AIO::poll_cb
		1162	while IO::AIO::nreqs;
		1163
		1164	=item IO::AIO::nready
		1165
		1166	Returns the number of requests currently in the ready state (not yet
		1167	executed).
		1168
		1169	=item IO::AIO::npending
		1170
		1171	Returns the number of requests currently in the pending state (executed,
		1172	but not yet processed by poll_cb).
860		1173
861	=back	1174	=back
862		1175
863	=cut	1176	=cut
864		1177
…		…
878	*$sym	1191	*$sym
879	}	1192	}
880		1193
881	min_parallel 8;	1194	min_parallel 8;
882		1195
883	END {	1196	END { flush }
884	max_parallel 0;
885	}
886		1197
887	1;	1198	1;
888		1199
889	=head2 FORK BEHAVIOUR	1200	=head2 FORK BEHAVIOUR
890		1201
891	This module should do "the right thing" when the process using it forks:	1202	This module should do "the right thing" when the process using it forks:
892		1203
893	Before the fork, IO::AIO enters a quiescent state where no requests	1204	Before the fork, IO::AIO enters a quiescent state where no requests
894	can be added in other threads and no results will be processed. After	1205	can be added in other threads and no results will be processed. After
895	the fork the parent simply leaves the quiescent state and continues	1206	the fork the parent simply leaves the quiescent state and continues
896	request/result processing, while the child clears the request/result	1207	request/result processing, while the child frees the request/result queue
897	queue (so the requests started before the fork will only be handled in	1208	(so that the requests started before the fork will only be handled in the
898	the parent). Threads will be started on demand until the limit ste in the	1209	parent). Threads will be started on demand until the limit set in the
899	parent process has been reached again.	1210	parent process has been reached again.
900		1211
901	In short: the parent will, after a short pause, continue as if fork had	1212	In short: the parent will, after a short pause, continue as if fork had
902	not been called, while the child will act as if IO::AIO has not been used	1213	not been called, while the child will act as if IO::AIO has not been used
903	yet.	1214	yet.
904		1215
905	=head2 MEMORY USAGE	1216	=head2 MEMORY USAGE
906		1217
		1218	Per-request usage:
		1219
907	Each aio request uses - depending on your architecture - around 128 bytes	1220	Each aio request uses - depending on your architecture - around 100-200
908	of memory. In addition, stat requests need a stat buffer (possibly a few	1221	bytes of memory. In addition, stat requests need a stat buffer (possibly
909	hundred bytes). Perl scalars and other data passed into aio requests will	1222	a few hundred bytes), readdir requires a result buffer and so on. Perl
910	also be locked.	1223	scalars and other data passed into aio requests will also be locked and
		1224	will consume memory till the request has entered the done state.
911		1225
912	This is now awfully much, so queuing lots of requests is not usually a	1226	This is now awfully much, so queuing lots of requests is not usually a
913	problem.	1227	problem.
914		1228
915	Each thread needs a stack area which is usually around 16k, sometimes much	1229	Per-thread usage:
916	larger, depending on the OS.	1230
		1231	In the execution phase, some aio requests require more memory for
		1232	temporary buffers, and each thread requires a stack and other data
		1233	structures (usually around 16k-128k, depending on the OS).
		1234
		1235	=head1 KNOWN BUGS
		1236
		1237	Known bugs will be fixed in the next release.
917		1238
918	=head1 SEE ALSO	1239	=head1 SEE ALSO
919		1240
920	L<Coro::AIO>.	1241	L<Coro::AIO>.
921		1242

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC vs. Revision 1.102 by root, Mon Jan 8 20:45:04 2007 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC vs.
Revision 1.102 by root, Mon Jan 8 20:45:04 2007 UTC