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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs.
Revision 1.120 by root, Sun Dec 2 21:51:36 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
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration	31	# AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...)
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";	32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });	33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
		34
		35	# EV integration
		36	my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
33		37
34	# Event integration	38	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,	39	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',	40	poll => 'r',
37	cb => \&IO::AIO::poll_cb);	41	cb => \&IO::AIO::poll_cb);
…		…
50		54
51	=head1 DESCRIPTION	55	=head1 DESCRIPTION
52		56
53	This module implements asynchronous I/O using whatever means your	57	This module implements asynchronous I/O using whatever means your
54	operating system supports.	58	operating system supports.
		59
		60	Asynchronous means that operations that can normally block your program
		61	(e.g. reading from disk) will be done asynchronously: the operation
		62	will still block, but you can do something else in the meantime. This
		63	is extremely useful for programs that need to stay interactive even
		64	when doing heavy I/O (GUI programs, high performance network servers
		65	etc.), but can also be used to easily do operations in parallel that are
		66	normally done sequentially, e.g. stat'ing many files, which is much faster
		67	on a RAID volume or over NFS when you do a number of stat operations
		68	concurrently.
		69
		70	While most of this works on all types of file descriptors (for
		71	example sockets), using these functions on file descriptors that
		72	support nonblocking operation (again, sockets, pipes etc.) is very
		73	inefficient. Use an event loop for that (such as the L<Event\|Event>
		74	module): IO::AIO will naturally fit into such an event loop itself.
55		75
56	In this version, a number of threads are started that execute your	76	In this version, a number of threads are started that execute your
57	requests and signal their completion. You don't need thread support	77	requests and signal their completion. You don't need thread support
58	in perl, and the threads created by this module will not be visible	78	in perl, and the threads created by this module will not be visible
59	to perl. In the future, this module might make use of the native aio	79	to perl. In the future, this module might make use of the native aio
60	functions available on many operating systems. However, they are often	80	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	81	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	files currently, for example), and they would only support aio_read and	82	files currently, for example), and they would only support aio_read and
63	aio_write, so the remaining functionality would have to be implemented	83	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	84	using threads anyway.
65		85
66	Although the module will work with in the presence of other (Perl-)	86	Although the module will work in the presence of other (Perl-) threads,
67	threads, it is currently not reentrant in any way, so use appropriate	87	it is currently not reentrant in any way, so use appropriate locking
68	locking yourself, always call C<poll_cb> from within the same thread, or	88	yourself, always call C<poll_cb> from within the same thread, or never
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	89	call C<poll_cb> (or other C<aio_> functions) recursively.
		90
		91	=head2 EXAMPLE
		92
		93	This is a simple example that uses the Event module and loads
		94	F</etc/passwd> asynchronously:
		95
		96	use Fcntl;
		97	use Event;
		98	use IO::AIO;
		99
		100	# register the IO::AIO callback with Event
		101	Event->io (fd => IO::AIO::poll_fileno,
		102	poll => 'r',
		103	cb => \&IO::AIO::poll_cb);
		104
		105	# queue the request to open /etc/passwd
		106	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		107	my $fh = shift
		108	or die "error while opening: $!";
		109
		110	# stat'ing filehandles is generally non-blocking
		111	my $size = -s $fh;
		112
		113	# queue a request to read the file
		114	my $contents;
		115	aio_read $fh, 0, $size, $contents, 0, sub {
		116	$_[0] == $size
		117	or die "short read: $!";
		118
		119	close $fh;
		120
		121	# file contents now in $contents
		122	print $contents;
		123
		124	# exit event loop and program
		125	Event::unloop;
		126	};
		127	};
		128
		129	# possibly queue up other requests, or open GUI windows,
		130	# check for sockets etc. etc.
		131
		132	# process events as long as there are some:
		133	Event::loop;
70		134
71	=head1 REQUEST ANATOMY AND LIFETIME	135	=head1 REQUEST ANATOMY AND LIFETIME
72		136
73	Every C<aio_*> function creates a request. which is a C data structure not	137	Every C<aio_*> function creates a request. which is a C data structure not
74	directly visible to Perl.	138	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	180	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	181	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	182	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	183	result in a runtime error).
120		184
		185	=back
		186
121	=cut	187	=cut
122		188
123	package IO::AIO;	189	package IO::AIO;
		190
		191	use Carp ();
124		192
125	no warnings;	193	no warnings;
126	use strict 'vars';	194	use strict 'vars';
127		195
128	use base 'Exporter';	196	use base 'Exporter';
129		197
130	BEGIN {	198	BEGIN {
131	our $VERSION = '2.0';	199	our $VERSION = '2.6';
132		200
133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	201	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	202	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	203	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136	aio_copy aio_group aio_nop aio_mknod);	204	aio_fdatasync aio_pathsync aio_readahead
		205	aio_rename aio_link aio_move aio_copy aio_group
		206	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		207	aio_chmod aio_utime aio_truncate);
		208
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	209	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	210	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs nready npending);	211	min_parallel max_parallel max_idle
		212	nreqs nready npending nthreads
		213	max_poll_time max_poll_reqs);
140		214
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	215	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		216
143	require XSLoader;	217	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	218	XSLoader::load ("IO::AIO", $VERSION);
145	}	219	}
146		220
147	=head1 FUNCTIONS	221	=head1 FUNCTIONS
148		222
149	=head2 AIO FUNCTIONS	223	=head2 AIO REQUEST FUNCTIONS
150		224
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	225	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	226	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	227	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	228	which must be a code reference. This code reference will get called with
…		…
157	syscall has been executed asynchronously.	231	syscall has been executed asynchronously.
158		232
159	All functions expecting a filehandle keep a copy of the filehandle	233	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	234	internally until the request has finished.
161		235
162	All requests return objects of type L<IO::AIO::REQ> that allow further	236	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	237	further manipulation of those requests while they are in-flight.
164		238
165	The pathnames you pass to these routines I<must> be absolute and	239	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	240	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	241	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	242	changed. Alternatively, you can make sure that you never change the
169	current working directory.	243	current working directory anywhere in the program and then use relative
		244	paths.
170		245
171	To encode pathnames to byte form, either make sure you either: a)	246	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	247	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	248	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	249	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	250	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	251	use something else to ensure your scalar has the correct contents.
		252
		253	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		254	handles correctly wether it is set or not.
177		255
178	=over 4	256	=over 4
179		257
180	=item $prev_pri = aioreq_pri [$pri]	258	=item $prev_pri = aioreq_pri [$pri]
181		259
…		…
201	aio_read $_[0], ..., sub {	279	aio_read $_[0], ..., sub {
202	...	280	...
203	};	281	};
204	};	282	};
205		283
		284
206	=item aioreq_nice $pri_adjust	285	=item aioreq_nice $pri_adjust
207		286
208	Similar to C<aioreq_pri>, but subtracts the given value from the current	287	Similar to C<aioreq_pri>, but subtracts the given value from the current
209	priority, so effects are cumulative.	288	priority, so the effect is cumulative.
		289
210		290
211	=item aio_open $pathname, $flags, $mode, $callback->($fh)	291	=item aio_open $pathname, $flags, $mode, $callback->($fh)
212		292
213	Asynchronously open or create a file and call the callback with a newly	293	Asynchronously open or create a file and call the callback with a newly
214	created filehandle for the file.	294	created filehandle for the file.
…		…
220	list. They are the same as used by C<sysopen>.	300	list. They are the same as used by C<sysopen>.
221		301
222	Likewise, C<$mode> specifies the mode of the newly created file, if it	302	Likewise, C<$mode> specifies the mode of the newly created file, if it
223	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	303	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224	except that it is mandatory (i.e. use C<0> if you don't create new files,	304	except that it is mandatory (i.e. use C<0> if you don't create new files,
225	and C<0666> or C<0777> if you do).	305	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		306	by the umask in effect then the request is being executed, so better never
		307	change the umask.
226		308
227	Example:	309	Example:
228		310
229	aio_open "/etc/passwd", O_RDONLY, 0, sub {	311	aio_open "/etc/passwd", O_RDONLY, 0, sub {
230	if ($_[0]) {	312	if ($_[0]) {
…		…
233	} else {	315	} else {
234	die "open failed: $!\n";	316	die "open failed: $!\n";
235	}	317	}
236	};	318	};
237		319
		320
238	=item aio_close $fh, $callback->($status)	321	=item aio_close $fh, $callback->($status)
239		322
240	Asynchronously close a file and call the callback with the result	323	Asynchronously close a file and call the callback with the result
241	code. I<WARNING:> although accepted, you should not pass in a perl	324	code.
242	filehandle here, as perl will likely close the file descriptor another
243	time when the filehandle is destroyed. Normally, you can safely call perls
244	C<close> or just let filehandles go out of scope.
245		325
246	This is supposed to be a bug in the API, so that might change. It's	326	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247	therefore best to avoid this function.	327	closing the file descriptor associated with the filehandle itself. Here is
		328	what aio_close will try:
		329
		330	1. dup()licate the fd
		331	2. asynchronously close() the duplicated fd
		332	3. dup()licate the fd once more
		333	4. let perl close() the filehandle
		334	5. asynchronously close the duplicated fd
		335
		336	The idea is that the first close() flushes stuff to disk that closing an
		337	fd will flush, so when perl closes the fd, nothing much will need to be
		338	flushed. The second async. close() will then flush stuff to disk that
		339	closing the last fd to the file will flush.
		340
		341	Just FYI, SuSv3 has this to say on close:
		342
		343	All outstanding record locks owned by the process on the file
		344	associated with the file descriptor shall be removed.
		345
		346	If fildes refers to a socket, close() shall cause the socket to be
		347	destroyed. ... close() shall block for up to the current linger
		348	interval until all data is transmitted.
		349	[this actually sounds like a specification bug, but who knows]
		350
		351	And at least Linux additionally actually flushes stuff on every close,
		352	even when the file itself is still open.
		353
		354	Sounds enourmously inefficient and complicated? Yes... please show me how
		355	to nuke perl's fd out of existence...
		356
		357	=cut
		358
		359	sub aio_close($;$) {
		360	aio_block {
		361	my ($fh, $cb) = @_;
		362
		363	my $pri = aioreq_pri;
		364	my $grp = aio_group $cb;
		365
		366	my $fd = fileno $fh;
		367
		368	defined $fd or Carp::croak "aio_close called with fd-less filehandle";
		369
		370	# if the dups fail we will simply get EBADF
		371	my $fd2 = _dup $fd;
		372	aioreq_pri $pri;
		373	add $grp _aio_close $fd2, sub {
		374	my $fd2 = _dup $fd;
		375	close $fh;
		376	aioreq_pri $pri;
		377	add $grp _aio_close $fd2, sub {
		378	$grp->result ($_[0]);
		379	};
		380	};
		381
		382	$grp
		383	}
		384	}
		385
248		386
249	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	387	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250		388
251	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	389	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252		390
253	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	391	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254	into the scalar given by C<data> and offset C<dataoffset> and calls the	392	into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255	callback without the actual number of bytes read (or -1 on error, just	393	callback without the actual number of bytes read (or -1 on error, just
256	like the syscall).	394	like the syscall).
257		395
		396	If C<$offset> is undefined, then the current file descriptor offset will
		397	be used (and updated), otherwise the file descriptor offset will not be
		398	changed by these calls.
		399
		400	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
		401
		402	If C<$dataoffset> is less than zero, it will be counted from the end of
		403	C<$data>.
		404
258	The C<$data> scalar I<MUST NOT> be modified in any way while the request	405	The C<$data> scalar I<MUST NOT> be modified in any way while the request
259	is outstanding. Modifying it can result in segfaults or WW3 (if the	406	is outstanding. Modifying it can result in segfaults or World War III (if
260	necessary/optional hardware is installed).	407	the necessary/optional hardware is installed).
261		408
262	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	409	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263	offset C<0> within the scalar:	410	offset C<0> within the scalar:
264		411
265	aio_read $fh, 7, 15, $buffer, 0, sub {	412	aio_read $fh, 7, 15, $buffer, 0, sub {
266	$_[0] > 0 or die "read error: $!";	413	$_[0] > 0 or die "read error: $!";
267	print "read $_[0] bytes: <$buffer>\n";	414	print "read $_[0] bytes: <$buffer>\n";
268	};	415	};
		416
269		417
270	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	418	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
271		419
272	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	420	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
273	reading at byte offset C<$in_offset>, and starts writing at the current	421	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
287	C<$in_fh> than are written, and there is no way to find out how many	435	C<$in_fh> than are written, and there is no way to find out how many
288	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	436	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
289	provides the number of bytes written to C<$out_fh>. Only if the result	437	provides the number of bytes written to C<$out_fh>. Only if the result
290	value equals C<$length> one can assume that C<$length> bytes have been	438	value equals C<$length> one can assume that C<$length> bytes have been
291	read.	439	read.
		440
292		441
293	=item aio_readahead $fh,$offset,$length, $callback->($retval)	442	=item aio_readahead $fh,$offset,$length, $callback->($retval)
294		443
295	C<aio_readahead> populates the page cache with data from a file so that	444	C<aio_readahead> populates the page cache with data from a file so that
296	subsequent reads from that file will not block on disk I/O. The C<$offset>	445	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
302	file. The current file offset of the file is left unchanged.	451	file. The current file offset of the file is left unchanged.
303		452
304	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	453	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
305	emulated by simply reading the data, which would have a similar effect.	454	emulated by simply reading the data, which would have a similar effect.
306		455
		456
307	=item aio_stat $fh_or_path, $callback->($status)	457	=item aio_stat $fh_or_path, $callback->($status)
308		458
309	=item aio_lstat $fh, $callback->($status)	459	=item aio_lstat $fh, $callback->($status)
310		460
311	Works like perl's C<stat> or C<lstat> in void context. The callback will	461	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
324	aio_stat "/etc/passwd", sub {	474	aio_stat "/etc/passwd", sub {
325	$_[0] and die "stat failed: $!";	475	$_[0] and die "stat failed: $!";
326	print "size is ", -s _, "\n";	476	print "size is ", -s _, "\n";
327	};	477	};
328		478
		479
		480	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		481
		482	Works like perl's C<utime> function (including the special case of $atime
		483	and $mtime being undef). Fractional times are supported if the underlying
		484	syscalls support them.
		485
		486	When called with a pathname, uses utimes(2) if available, otherwise
		487	utime(2). If called on a file descriptor, uses futimes(2) if available,
		488	otherwise returns ENOSYS, so this is not portable.
		489
		490	Examples:
		491
		492	# set atime and mtime to current time (basically touch(1)):
		493	aio_utime "path", undef, undef;
		494	# set atime to current time and mtime to beginning of the epoch:
		495	aio_utime "path", time, undef; # undef==0
		496
		497
		498	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		499
		500	Works like perl's C<chown> function, except that C<undef> for either $uid
		501	or $gid is being interpreted as "do not change" (but -1 can also be used).
		502
		503	Examples:
		504
		505	# same as "chown root path" in the shell:
		506	aio_chown "path", 0, -1;
		507	# same as above:
		508	aio_chown "path", 0, undef;
		509
		510
		511	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		512
		513	Works like truncate(2) or ftruncate(2).
		514
		515
		516	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		517
		518	Works like perl's C<chmod> function.
		519
		520
329	=item aio_unlink $pathname, $callback->($status)	521	=item aio_unlink $pathname, $callback->($status)
330		522
331	Asynchronously unlink (delete) a file and call the callback with the	523	Asynchronously unlink (delete) a file and call the callback with the
332	result code.	524	result code.
333		525
		526
334	=item aio_mknod $path, $mode, $dev, $callback->($status)	527	=item aio_mknod $path, $mode, $dev, $callback->($status)
335		528
		529	[EXPERIMENTAL]
		530
336	Asynchronously create a device node (or fifo). See mknod(2): the only	531	Asynchronously create a device node (or fifo). See mknod(2).
337	portable value for C<$mode> is C<S_IFIFO> ored with permissions, and C<0>	532
338	for C<$dev>.	533	The only (POSIX-) portable way of calling this function is:
		534
		535	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		536
339		537
340	=item aio_link $srcpath, $dstpath, $callback->($status)	538	=item aio_link $srcpath, $dstpath, $callback->($status)
341		539
342	Asynchronously create a new link to the existing object at C<$srcpath> at	540	Asynchronously create a new link to the existing object at C<$srcpath> at
343	the path C<$dstpath> and call the callback with the result code.	541	the path C<$dstpath> and call the callback with the result code.
344		542
		543
345	=item aio_symlink $srcpath, $dstpath, $callback->($status)	544	=item aio_symlink $srcpath, $dstpath, $callback->($status)
346		545
347	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	546	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
348	the path C<$dstpath> and call the callback with the result code.	547	the path C<$dstpath> and call the callback with the result code.
349		548
		549
		550	=item aio_readlink $path, $callback->($link)
		551
		552	Asynchronously read the symlink specified by C<$path> and pass it to
		553	the callback. If an error occurs, nothing or undef gets passed to the
		554	callback.
		555
		556
350	=item aio_rename $srcpath, $dstpath, $callback->($status)	557	=item aio_rename $srcpath, $dstpath, $callback->($status)
351		558
352	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	559	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
353	rename(2) and call the callback with the result code.	560	rename(2) and call the callback with the result code.
354		561
		562
		563	=item aio_mkdir $pathname, $mode, $callback->($status)
		564
		565	Asynchronously mkdir (create) a directory and call the callback with
		566	the result code. C<$mode> will be modified by the umask at the time the
		567	request is executed, so do not change your umask.
		568
		569
355	=item aio_rmdir $pathname, $callback->($status)	570	=item aio_rmdir $pathname, $callback->($status)
356		571
357	Asynchronously rmdir (delete) a directory and call the callback with the	572	Asynchronously rmdir (delete) a directory and call the callback with the
358	result code.	573	result code.
		574
359		575
360	=item aio_readdir $pathname, $callback->($entries)	576	=item aio_readdir $pathname, $callback->($entries)
361		577
362	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	578	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
363	directory (i.e. opendir + readdir + closedir). The entries will not be	579	directory (i.e. opendir + readdir + closedir). The entries will not be
364	sorted, and will B<NOT> include the C<.> and C<..> entries.	580	sorted, and will B<NOT> include the C<.> and C<..> entries.
365		581
366	The callback a single argument which is either C<undef> or an array-ref	582	The callback a single argument which is either C<undef> or an array-ref
367	with the filenames.	583	with the filenames.
		584
		585
		586	=item aio_load $path, $data, $callback->($status)
		587
		588	This is a composite request that tries to fully load the given file into
		589	memory. Status is the same as with aio_read.
		590
		591	=cut
		592
		593	sub aio_load($$;$) {
		594	aio_block {
		595	my ($path, undef, $cb) = @_;
		596	my $data = \$_[1];
		597
		598	my $pri = aioreq_pri;
		599	my $grp = aio_group $cb;
		600
		601	aioreq_pri $pri;
		602	add $grp aio_open $path, O_RDONLY, 0, sub {
		603	my $fh = shift
		604	or return $grp->result (-1);
		605
		606	aioreq_pri $pri;
		607	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		608	$grp->result ($_[0]);
		609	};
		610	};
		611
		612	$grp
		613	}
		614	}
368		615
369	=item aio_copy $srcpath, $dstpath, $callback->($status)	616	=item aio_copy $srcpath, $dstpath, $callback->($status)
370		617
371	Try to copy the I<file> (directories not supported as either source or	618	Try to copy the I<file> (directories not supported as either source or
372	destination) from C<$srcpath> to C<$dstpath> and call the callback with	619	destination) from C<$srcpath> to C<$dstpath> and call the callback with
…		…
382	errors are being ignored.	629	errors are being ignored.
383		630
384	=cut	631	=cut
385		632
386	sub aio_copy($$;$) {	633	sub aio_copy($$;$) {
		634	aio_block {
387	my ($src, $dst, $cb) = @_;	635	my ($src, $dst, $cb) = @_;
388		636
389	my $pri = aioreq_pri;	637	my $pri = aioreq_pri;
390	my $grp = aio_group $cb;	638	my $grp = aio_group $cb;
391		639
392	aioreq_pri $pri;	640	aioreq_pri $pri;
393	add $grp aio_open $src, O_RDONLY, 0, sub {	641	add $grp aio_open $src, O_RDONLY, 0, sub {
394	if (my $src_fh = $_[0]) {	642	if (my $src_fh = $_[0]) {
395	my @stat = stat $src_fh;	643	my @stat = stat $src_fh;
396		644
397	aioreq_pri $pri;	645	aioreq_pri $pri;
398	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	646	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
399	if (my $dst_fh = $_[0]) {	647	if (my $dst_fh = $_[0]) {
400	aioreq_pri $pri;	648	aioreq_pri $pri;
401	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	649	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
402	if ($_[0] == $stat[7]) {	650	if ($_[0] == $stat[7]) {
403	$grp->result (0);	651	$grp->result (0);
404	close $src_fh;	652	close $src_fh;
405		653
406	# those should not normally block. should. should.	654	# those should not normally block. should. should.
407	utime $stat[8], $stat[9], $dst;	655	utime $stat[8], $stat[9], $dst;
408	chmod $stat[2] & 07777, $dst_fh;	656	chmod $stat[2] & 07777, $dst_fh;
409	chown $stat[4], $stat[5], $dst_fh;	657	chown $stat[4], $stat[5], $dst_fh;
		658
		659	aioreq_pri $pri;
410	close $dst_fh;	660	add $grp aio_close $dst_fh;
411	} else {	661	} else {
412	$grp->result (-1);	662	$grp->result (-1);
413	close $src_fh;	663	close $src_fh;
414	close $dst_fh;	664	close $dst_fh;
415		665
416	aioreq $pri;	666	aioreq $pri;
417	add $grp aio_unlink $dst;	667	add $grp aio_unlink $dst;
		668	}
418	}	669	};
		670	} else {
		671	$grp->result (-1);
419	};	672	}
420	} else {
421	$grp->result (-1);
422	}	673	},
		674
		675	} else {
		676	$grp->result (-1);
423	},	677	}
424
425	} else {
426	$grp->result (-1);
427	}	678	};
		679
		680	$grp
428	};	681	}
429
430	$grp
431	}	682	}
432		683
433	=item aio_move $srcpath, $dstpath, $callback->($status)	684	=item aio_move $srcpath, $dstpath, $callback->($status)
434		685
435	Try to move the I<file> (directories not supported as either source or	686	Try to move the I<file> (directories not supported as either source or
…		…
441	that is successful, unlinking the C<$srcpath>.	692	that is successful, unlinking the C<$srcpath>.
442		693
443	=cut	694	=cut
444		695
445	sub aio_move($$;$) {	696	sub aio_move($$;$) {
		697	aio_block {
446	my ($src, $dst, $cb) = @_;	698	my ($src, $dst, $cb) = @_;
447		699
448	my $pri = aioreq_pri;	700	my $pri = aioreq_pri;
449	my $grp = aio_group $cb;	701	my $grp = aio_group $cb;
450		702
451	aioreq_pri $pri;	703	aioreq_pri $pri;
452	add $grp aio_rename $src, $dst, sub {	704	add $grp aio_rename $src, $dst, sub {
453	if ($_[0] && $! == EXDEV) {	705	if ($_[0] && $! == EXDEV) {
454	aioreq_pri $pri;	706	aioreq_pri $pri;
455	add $grp aio_copy $src, $dst, sub {	707	add $grp aio_copy $src, $dst, sub {
		708	$grp->result ($_[0]);
		709
		710	if (!$_[0]) {
		711	aioreq_pri $pri;
		712	add $grp aio_unlink $src;
		713	}
		714	};
		715	} else {
456	$grp->result ($_[0]);	716	$grp->result ($_[0]);
457
458	if (!$_[0]) {
459	aioreq_pri $pri;
460	add $grp aio_unlink $src;
461	}
462	};	717	}
463	} else {
464	$grp->result ($_[0]);
465	}	718	};
		719
		720	$grp
466	};	721	}
467
468	$grp
469	}	722	}
470		723
471	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	724	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
472		725
473	Scans a directory (similar to C<aio_readdir>) but additionally tries to	726	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
520	as those tend to return 0 or 1 as link counts, which disables the	773	as those tend to return 0 or 1 as link counts, which disables the
521	directory counting heuristic.	774	directory counting heuristic.
522		775
523	=cut	776	=cut
524		777
525	sub aio_scandir($$$) {	778	sub aio_scandir($$;$) {
		779	aio_block {
526	my ($path, $maxreq, $cb) = @_;	780	my ($path, $maxreq, $cb) = @_;
527		781
528	my $pri = aioreq_pri;	782	my $pri = aioreq_pri;
529		783
530	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
531		785
532	$maxreq = 4 if $maxreq <= 0;	786	$maxreq = 4 if $maxreq <= 0;
533		787
534	# stat once	788	# stat once
535	aioreq_pri $pri;
536	add $grp aio_stat $path, sub {
537	return $grp->result () if $_[0];
538	my $now = time;
539	my $hash1 = join ":", (stat _)[0,1,3,7,9];
540
541	# read the directory entries
542	aioreq_pri $pri;	789	aioreq_pri $pri;
543	add $grp aio_readdir $path, sub {	790	add $grp aio_stat $path, sub {
544	my $entries = shift
545	or return $grp->result ();	791	return $grp->result () if $_[0];
		792	my $now = time;
		793	my $hash1 = join ":", (stat _)[0,1,3,7,9];
546		794
547	# stat the dir another time	795	# read the directory entries
548	aioreq_pri $pri;	796	aioreq_pri $pri;
		797	add $grp aio_readdir $path, sub {
		798	my $entries = shift
		799	or return $grp->result ();
		800
		801	# stat the dir another time
		802	aioreq_pri $pri;
549	add $grp aio_stat $path, sub {	803	add $grp aio_stat $path, sub {
550	my $hash2 = join ":", (stat _)[0,1,3,7,9];	804	my $hash2 = join ":", (stat _)[0,1,3,7,9];
551		805
552	my $ndirs;	806	my $ndirs;
553		807
554	# take the slow route if anything looks fishy	808	# take the slow route if anything looks fishy
555	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	809	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
556	$ndirs = -1;	810	$ndirs = -1;
557	} else {	811	} else {
558	# if nlink == 2, we are finished	812	# if nlink == 2, we are finished
559	# on non-posix-fs's, we rely on nlink < 2	813	# on non-posix-fs's, we rely on nlink < 2
560	$ndirs = (stat _)[3] - 2	814	$ndirs = (stat _)[3] - 2
561	or return $grp->result ([], $entries);	815	or return $grp->result ([], $entries);
562	}	816	}
563		817
564	# sort into likely dirs and likely nondirs	818	# sort into likely dirs and likely nondirs
565	# dirs == files without ".", short entries first	819	# dirs == files without ".", short entries first
566	$entries = [map $_->[0],	820	$entries = [map $_->[0],
567	sort { $b->[1] cmp $a->[1] }	821	sort { $b->[1] cmp $a->[1] }
568	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	822	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
569	@$entries];	823	@$entries];
570		824
571	my (@dirs, @nondirs);	825	my (@dirs, @nondirs);
572		826
573	my $statgrp = add $grp aio_group sub {	827	my $statgrp = add $grp aio_group sub {
574	$grp->result (\@dirs, \@nondirs);	828	$grp->result (\@dirs, \@nondirs);
575	};	829	};
576		830
577	limit $statgrp $maxreq;	831	limit $statgrp $maxreq;
578	feed $statgrp sub {	832	feed $statgrp sub {
579	return unless @$entries;	833	return unless @$entries;
580	my $entry = pop @$entries;	834	my $entry = pop @$entries;
581		835
582	aioreq_pri $pri;	836	aioreq_pri $pri;
583	add $statgrp aio_stat "$path/$entry/.", sub {	837	add $statgrp aio_stat "$path/$entry/.", sub {
584	if ($_[0] < 0) {	838	if ($_[0] < 0) {
585	push @nondirs, $entry;	839	push @nondirs, $entry;
586	} else {	840	} else {
587	# need to check for real directory	841	# need to check for real directory
588	aioreq_pri $pri;	842	aioreq_pri $pri;
589	add $statgrp aio_lstat "$path/$entry", sub {	843	add $statgrp aio_lstat "$path/$entry", sub {
590	if (-d _) {	844	if (-d _) {
591	push @dirs, $entry;	845	push @dirs, $entry;
592		846
593	unless (--$ndirs) {	847	unless (--$ndirs) {
594	push @nondirs, @$entries;	848	push @nondirs, @$entries;
595	feed $statgrp;	849	feed $statgrp;
		850	}
		851	} else {
		852	push @nondirs, $entry;
596	}	853	}
597	} else {
598	push @nondirs, $entry;
599	}	854	}
600	}	855	}
601	}	856	};
602	};	857	};
603	};	858	};
604	};	859	};
605	};	860	};
		861
		862	$grp
606	};	863	}
607
608	$grp
609	}	864	}
		865
		866	=item aio_rmtree $path, $callback->($status)
		867
		868	Delete a directory tree starting (and including) C<$path>, return the
		869	status of the final C<rmdir> only. This is a composite request that
		870	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		871	everything else.
		872
		873	=cut
		874
		875	sub aio_rmtree;
		876	sub aio_rmtree($;$) {
		877	aio_block {
		878	my ($path, $cb) = @_;
		879
		880	my $pri = aioreq_pri;
		881	my $grp = aio_group $cb;
		882
		883	aioreq_pri $pri;
		884	add $grp aio_scandir $path, 0, sub {
		885	my ($dirs, $nondirs) = @_;
		886
		887	my $dirgrp = aio_group sub {
		888	add $grp aio_rmdir $path, sub {
		889	$grp->result ($_[0]);
		890	};
		891	};
		892
		893	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		894	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		895
		896	add $grp $dirgrp;
		897	};
		898
		899	$grp
		900	}
		901	}
		902
		903	=item aio_sync $callback->($status)
		904
		905	Asynchronously call sync and call the callback when finished.
610		906
611	=item aio_fsync $fh, $callback->($status)	907	=item aio_fsync $fh, $callback->($status)
612		908
613	Asynchronously call fsync on the given filehandle and call the callback	909	Asynchronously call fsync on the given filehandle and call the callback
614	with the fsync result code.	910	with the fsync result code.
…		…
618	Asynchronously call fdatasync on the given filehandle and call the	914	Asynchronously call fdatasync on the given filehandle and call the
619	callback with the fdatasync result code.	915	callback with the fdatasync result code.
620		916
621	If this call isn't available because your OS lacks it or it couldn't be	917	If this call isn't available because your OS lacks it or it couldn't be
622	detected, it will be emulated by calling C<fsync> instead.	918	detected, it will be emulated by calling C<fsync> instead.
		919
		920	=item aio_pathsync $path, $callback->($status)
		921
		922	This request tries to open, fsync and close the given path. This is a
		923	composite request intended tosync directories after directory operations
		924	(E.g. rename). This might not work on all operating systems or have any
		925	specific effect, but usually it makes sure that directory changes get
		926	written to disc. It works for anything that can be opened for read-only,
		927	not just directories.
		928
		929	Passes C<0> when everything went ok, and C<-1> on error.
		930
		931	=cut
		932
		933	sub aio_pathsync($;$) {
		934	aio_block {
		935	my ($path, $cb) = @_;
		936
		937	my $pri = aioreq_pri;
		938	my $grp = aio_group $cb;
		939
		940	aioreq_pri $pri;
		941	add $grp aio_open $path, O_RDONLY, 0, sub {
		942	my ($fh) = @_;
		943	if ($fh) {
		944	aioreq_pri $pri;
		945	add $grp aio_fsync $fh, sub {
		946	$grp->result ($_[0]);
		947
		948	aioreq_pri $pri;
		949	add $grp aio_close $fh;
		950	};
		951	} else {
		952	$grp->result (-1);
		953	}
		954	};
		955
		956	$grp
		957	}
		958	}
623		959
624	=item aio_group $callback->(...)	960	=item aio_group $callback->(...)
625		961
626	This is a very special aio request: Instead of doing something, it is a	962	This is a very special aio request: Instead of doing something, it is a
627	container for other aio requests, which is useful if you want to bundle	963	container for other aio requests, which is useful if you want to bundle
…		…
764	itself. Useful when you queued a lot of events but got a result early.	1100	itself. Useful when you queued a lot of events but got a result early.
765		1101
766	=item $grp->result (...)	1102	=item $grp->result (...)
767		1103
768	Set the result value(s) that will be passed to the group callback when all	1104	Set the result value(s) that will be passed to the group callback when all
769	subrequests have finished and set thre groups errno to the current value	1105	subrequests have finished and set the groups errno to the current value
770	of errno (just like calling C<errno> without an error number). By default,	1106	of errno (just like calling C<errno> without an error number). By default,
771	no argument will be passed and errno is zero.	1107	no argument will be passed and errno is zero.
772		1108
773	=item $grp->errno ([$errno])	1109	=item $grp->errno ([$errno])
774		1110
…		…
827		1163
828	=back	1164	=back
829		1165
830	=head2 SUPPORT FUNCTIONS	1166	=head2 SUPPORT FUNCTIONS
831		1167
		1168	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1169
832	=over 4	1170	=over 4
833		1171
834	=item $fileno = IO::AIO::poll_fileno	1172	=item $fileno = IO::AIO::poll_fileno
835		1173
836	Return the I<request result pipe file descriptor>. This filehandle must be	1174	Return the I<request result pipe file descriptor>. This filehandle must be
…		…
840		1178
841	See C<poll_cb> for an example.	1179	See C<poll_cb> for an example.
842		1180
843	=item IO::AIO::poll_cb	1181	=item IO::AIO::poll_cb
844		1182
845	Process all outstanding events on the result pipe. You have to call this	1183	Process some outstanding events on the result pipe. You have to call this
846	regularly. Returns the number of events processed. Returns immediately	1184	regularly. Returns the number of events processed. Returns immediately
847	when no events are outstanding.	1185	when no events are outstanding. The amount of events processed depends on
		1186	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
848		1187
849	If not all requests were processed for whatever reason, the filehandle	1188	If not all requests were processed for whatever reason, the filehandle
850	will still be ready when C<poll_cb> returns.	1189	will still be ready when C<poll_cb> returns.
851		1190
852	Example: Install an Event watcher that automatically calls	1191	Example: Install an Event watcher that automatically calls
…		…
854		1193
855	Event->io (fd => IO::AIO::poll_fileno,	1194	Event->io (fd => IO::AIO::poll_fileno,
856	poll => 'r', async => 1,	1195	poll => 'r', async => 1,
857	cb => \&IO::AIO::poll_cb);	1196	cb => \&IO::AIO::poll_cb);
858		1197
859	=item IO::AIO::poll_some $max_requests	1198	=item IO::AIO::max_poll_reqs $nreqs
860		1199
861	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1200	=item IO::AIO::max_poll_time $seconds
862	at a time.
863		1201
864	Useful if you want to ensure some level of interactiveness when perl is	1202	These set the maximum number of requests (default C<0>, meaning infinity)
865	not fast enough to process all requests in time.	1203	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1204	the maximum amount of time (default C<0>, meaning infinity) spent in
		1205	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1206	of time C<poll_cb> is allowed to use).
		1207
		1208	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1209	syscall per request processed, which is not normally a problem unless your
		1210	callbacks are really really fast or your OS is really really slow (I am
		1211	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1212
		1213	Setting these is useful if you want to ensure some level of
		1214	interactiveness when perl is not fast enough to process all requests in
		1215	time.
		1216
		1217	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
866		1218
867	Example: Install an Event watcher that automatically calls	1219	Example: Install an Event watcher that automatically calls
868	IO::AIO::poll_some with low priority, to ensure that other parts of the	1220	IO::AIO::poll_cb with low priority, to ensure that other parts of the
869	program get the CPU sometimes even under high AIO load.	1221	program get the CPU sometimes even under high AIO load.
870		1222
		1223	# try not to spend much more than 0.1s in poll_cb
		1224	IO::AIO::max_poll_time 0.1;
		1225
		1226	# use a low priority so other tasks have priority
871	Event->io (fd => IO::AIO::poll_fileno,	1227	Event->io (fd => IO::AIO::poll_fileno,
872	poll => 'r', nice => 1,	1228	poll => 'r', nice => 1,
873	cb => sub { IO::AIO::poll_some 256 });	1229	cb => &IO::AIO::poll_cb);
874		1230
875	=item IO::AIO::poll_wait	1231	=item IO::AIO::poll_wait
876		1232
		1233	If there are any outstanding requests and none of them in the result
877	Wait till the result filehandle becomes ready for reading (simply does a	1234	phase, wait till the result filehandle becomes ready for reading (simply
878	C<select> on the filehandle. This is useful if you want to synchronously wait	1235	does a C<select> on the filehandle. This is useful if you want to
879	for some requests to finish).	1236	synchronously wait for some requests to finish).
880		1237
881	See C<nreqs> for an example.	1238	See C<nreqs> for an example.
882		1239
		1240	=item IO::AIO::poll
		1241
		1242	Waits until some requests have been handled.
		1243
		1244	Returns the number of requests processed, but is otherwise strictly
		1245	equivalent to:
		1246
		1247	IO::AIO::poll_wait, IO::AIO::poll_cb
		1248
883	=item IO::AIO::nreqs	1249	=item IO::AIO::flush
884		1250
885	Returns the number of requests currently in the ready, execute or pending	1251	Wait till all outstanding AIO requests have been handled.
886	states (i.e. for which their callback has not been invoked yet).
887		1252
888	Example: wait till there are no outstanding requests anymore:	1253	Strictly equivalent to:
889		1254
890	IO::AIO::poll_wait, IO::AIO::poll_cb	1255	IO::AIO::poll_wait, IO::AIO::poll_cb
891	while IO::AIO::nreqs;	1256	while IO::AIO::nreqs;
892		1257
893	=item IO::AIO::nready	1258	=back
894		1259
895	Returns the number of requests currently in the ready state (not yet	1260	=head3 CONTROLLING THE NUMBER OF THREADS
896	executed).
897		1261
898	=item IO::AIO::npending	1262	=over
899
900	Returns the number of requests currently in the pending state (executed,
901	but not yet processed by poll_cb).
902
903	=item IO::AIO::flush
904
905	Wait till all outstanding AIO requests have been handled.
906
907	Strictly equivalent to:
908
909	IO::AIO::poll_wait, IO::AIO::poll_cb
910	while IO::AIO::nreqs;
911
912	=item IO::AIO::poll
913
914	Waits until some requests have been handled.
915
916	Strictly equivalent to:
917
918	IO::AIO::poll_wait, IO::AIO::poll_cb
919	if IO::AIO::nreqs;
920		1263
921	=item IO::AIO::min_parallel $nthreads	1264	=item IO::AIO::min_parallel $nthreads
922		1265
923	Set the minimum number of AIO threads to C<$nthreads>. The current	1266	Set the minimum number of AIO threads to C<$nthreads>. The current
924	default is C<8>, which means eight asynchronous operations can execute	1267	default is C<8>, which means eight asynchronous operations can execute
925	concurrently at any one time (the number of outstanding requests,	1268	concurrently at any one time (the number of outstanding requests,
926	however, is unlimited).	1269	however, is unlimited).
927		1270
928	IO::AIO starts threads only on demand, when an AIO request is queued and	1271	IO::AIO starts threads only on demand, when an AIO request is queued and
929	no free thread exists.	1272	no free thread exists. Please note that queueing up a hundred requests can
		1273	create demand for a hundred threads, even if it turns out that everything
		1274	is in the cache and could have been processed faster by a single thread.
930		1275
931	It is recommended to keep the number of threads relatively low, as some	1276	It is recommended to keep the number of threads relatively low, as some
932	Linux kernel versions will scale negatively with the number of threads	1277	Linux kernel versions will scale negatively with the number of threads
933	(higher parallelity => MUCH higher latency). With current Linux 2.6	1278	(higher parallelity => MUCH higher latency). With current Linux 2.6
934	versions, 4-32 threads should be fine.	1279	versions, 4-32 threads should be fine.
…		…
948	This module automatically runs C<max_parallel 0> at program end, to ensure	1293	This module automatically runs C<max_parallel 0> at program end, to ensure
949	that all threads are killed and that there are no outstanding requests.	1294	that all threads are killed and that there are no outstanding requests.
950		1295
951	Under normal circumstances you don't need to call this function.	1296	Under normal circumstances you don't need to call this function.
952		1297
		1298	=item IO::AIO::max_idle $nthreads
		1299
		1300	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1301	threads that did not get a request to process within 10 seconds). That
		1302	means if a thread becomes idle while C<$nthreads> other threads are also
		1303	idle, it will free its resources and exit.
		1304
		1305	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1306	to allow for extremely high load situations, but want to free resources
		1307	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1308
		1309	The default is probably ok in most situations, especially if thread
		1310	creation is fast. If thread creation is very slow on your system you might
		1311	want to use larger values.
		1312
953	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1313	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
954		1314
955	This is a very bad function to use in interactive programs because it	1315	This is a very bad function to use in interactive programs because it
956	blocks, and a bad way to reduce concurrency because it is inexact: Better	1316	blocks, and a bad way to reduce concurrency because it is inexact: Better
957	use an C<aio_group> together with a feed callback.	1317	use an C<aio_group> together with a feed callback.
958		1318
959	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1319	Sets the maximum number of outstanding requests to C<$nreqs>. If you
960	to queue up more than this number of requests, the next call to the	1320	do queue up more than this number of requests, the next call to the
961	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1321	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
962	function will block until the limit is no longer exceeded.	1322	function will block until the limit is no longer exceeded.
963		1323
964	The default value is very large, so there is no practical limit on the	1324	The default value is very large, so there is no practical limit on the
965	number of outstanding requests.	1325	number of outstanding requests.
…		…
968	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1328	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
969	as a stop gap to shield against fatal memory overflow (with large values).	1329	as a stop gap to shield against fatal memory overflow (with large values).
970		1330
971	=back	1331	=back
972		1332
		1333	=head3 STATISTICAL INFORMATION
		1334
		1335	=over
		1336
		1337	=item IO::AIO::nreqs
		1338
		1339	Returns the number of requests currently in the ready, execute or pending
		1340	states (i.e. for which their callback has not been invoked yet).
		1341
		1342	Example: wait till there are no outstanding requests anymore:
		1343
		1344	IO::AIO::poll_wait, IO::AIO::poll_cb
		1345	while IO::AIO::nreqs;
		1346
		1347	=item IO::AIO::nready
		1348
		1349	Returns the number of requests currently in the ready state (not yet
		1350	executed).
		1351
		1352	=item IO::AIO::npending
		1353
		1354	Returns the number of requests currently in the pending state (executed,
		1355	but not yet processed by poll_cb).
		1356
		1357	=back
		1358
973	=cut	1359	=cut
974		1360
975	# support function to convert a fd into a perl filehandle
976	sub _fd2fh {
977	return undef if $_[0] < 0;
978
979	# try to generate nice filehandles
980	my $sym = "IO::AIO::fd#$_[0]";
981	local *$sym;
982
983	open *$sym, "+<&=$_[0]" # usually works under any unix
984	or open *$sym, "<&=$_[0]" # cygwin needs this
985	or open *$sym, ">&=$_[0]" # or this
986	or return undef;
987
988	*$sym
989	}
990
991	min_parallel 8;	1361	min_parallel 8;
992		1362
993	END {	1363	END { flush }
994	flush;
995	};
996		1364
997	1;	1365	1;
998		1366
999	=head2 FORK BEHAVIOUR	1367	=head2 FORK BEHAVIOUR
1000		1368
…		…
1020	bytes of memory. In addition, stat requests need a stat buffer (possibly	1388	bytes of memory. In addition, stat requests need a stat buffer (possibly
1021	a few hundred bytes), readdir requires a result buffer and so on. Perl	1389	a few hundred bytes), readdir requires a result buffer and so on. Perl
1022	scalars and other data passed into aio requests will also be locked and	1390	scalars and other data passed into aio requests will also be locked and
1023	will consume memory till the request has entered the done state.	1391	will consume memory till the request has entered the done state.
1024		1392
1025	This is now awfully much, so queuing lots of requests is not usually a	1393	This is not awfully much, so queuing lots of requests is not usually a
1026	problem.	1394	problem.
1027		1395
1028	Per-thread usage:	1396	Per-thread usage:
1029		1397
1030	In the execution phase, some aio requests require more memory for	1398	In the execution phase, some aio requests require more memory for

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs. Revision 1.120 by root, Sun Dec 2 21:51:36 2007 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs.
Revision 1.120 by root, Sun Dec 2 21:51:36 2007 UTC