[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 1.124 by root, Sat May 10 19:25:33 2008 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 = '3.0';
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));
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.
		328
		329	Therefore, C<aio_close> will not close the filehandle - instead it will
		330	use dup2 to overwrite the file descriptor with the write-end of a pipe
		331	(the pipe fd will be created on demand and will be cached).
		332
		333	Or in other words: the file descriptor will be closed, but it will not be
		334	free for reuse until the perl filehandle is closed.
		335
		336	=cut
248		337
249	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	338	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250		339
251	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	340	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252		341
253	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	342	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254	into the scalar given by C<data> and offset C<dataoffset> and calls the	343	into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255	callback without the actual number of bytes read (or -1 on error, just	344	callback without the actual number of bytes read (or -1 on error, just
256	like the syscall).	345	like the syscall).
257		346
		347	If C<$offset> is undefined, then the current file descriptor offset will
		348	be used (and updated), otherwise the file descriptor offset will not be
		349	changed by these calls.
		350
		351	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
		352
		353	If C<$dataoffset> is less than zero, it will be counted from the end of
		354	C<$data>.
		355
258	The C<$data> scalar I<MUST NOT> be modified in any way while the request	356	The C<$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	357	is outstanding. Modifying it can result in segfaults or World War III (if
260	necessary/optional hardware is installed).	358	the necessary/optional hardware is installed).
261		359
262	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	360	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263	offset C<0> within the scalar:	361	offset C<0> within the scalar:
264		362
265	aio_read $fh, 7, 15, $buffer, 0, sub {	363	aio_read $fh, 7, 15, $buffer, 0, sub {
266	$_[0] > 0 or die "read error: $!";	364	$_[0] > 0 or die "read error: $!";
267	print "read $_[0] bytes: <$buffer>\n";	365	print "read $_[0] bytes: <$buffer>\n";
268	};	366	};
		367
269		368
270	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	369	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
271		370
272	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	371	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
273	reading at byte offset C<$in_offset>, and starts writing at the current	372	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
287	C<$in_fh> than are written, and there is no way to find out how many	386	C<$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	387	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
289	provides the number of bytes written to C<$out_fh>. Only if the result	388	provides the number of bytes written to C<$out_fh>. Only if the result
290	value equals C<$length> one can assume that C<$length> bytes have been	389	value equals C<$length> one can assume that C<$length> bytes have been
291	read.	390	read.
		391
292		392
293	=item aio_readahead $fh,$offset,$length, $callback->($retval)	393	=item aio_readahead $fh,$offset,$length, $callback->($retval)
294		394
295	C<aio_readahead> populates the page cache with data from a file so that	395	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<$offset>	396	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
302	file. The current file offset of the file is left unchanged.	402	file. The current file offset of the file is left unchanged.
303		403
304	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	404	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.	405	emulated by simply reading the data, which would have a similar effect.
306		406
		407
307	=item aio_stat $fh_or_path, $callback->($status)	408	=item aio_stat $fh_or_path, $callback->($status)
308		409
309	=item aio_lstat $fh, $callback->($status)	410	=item aio_lstat $fh, $callback->($status)
310		411
311	Works like perl's C<stat> or C<lstat> in void context. The callback will	412	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
324	aio_stat "/etc/passwd", sub {	425	aio_stat "/etc/passwd", sub {
325	$_[0] and die "stat failed: $!";	426	$_[0] and die "stat failed: $!";
326	print "size is ", -s _, "\n";	427	print "size is ", -s _, "\n";
327	};	428	};
328		429
		430
		431	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		432
		433	Works like perl's C<utime> function (including the special case of $atime
		434	and $mtime being undef). Fractional times are supported if the underlying
		435	syscalls support them.
		436
		437	When called with a pathname, uses utimes(2) if available, otherwise
		438	utime(2). If called on a file descriptor, uses futimes(2) if available,
		439	otherwise returns ENOSYS, so this is not portable.
		440
		441	Examples:
		442
		443	# set atime and mtime to current time (basically touch(1)):
		444	aio_utime "path", undef, undef;
		445	# set atime to current time and mtime to beginning of the epoch:
		446	aio_utime "path", time, undef; # undef==0
		447
		448
		449	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		450
		451	Works like perl's C<chown> function, except that C<undef> for either $uid
		452	or $gid is being interpreted as "do not change" (but -1 can also be used).
		453
		454	Examples:
		455
		456	# same as "chown root path" in the shell:
		457	aio_chown "path", 0, -1;
		458	# same as above:
		459	aio_chown "path", 0, undef;
		460
		461
		462	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		463
		464	Works like truncate(2) or ftruncate(2).
		465
		466
		467	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		468
		469	Works like perl's C<chmod> function.
		470
		471
329	=item aio_unlink $pathname, $callback->($status)	472	=item aio_unlink $pathname, $callback->($status)
330		473
331	Asynchronously unlink (delete) a file and call the callback with the	474	Asynchronously unlink (delete) a file and call the callback with the
332	result code.	475	result code.
333		476
		477
334	=item aio_mknod $path, $mode, $dev, $callback->($status)	478	=item aio_mknod $path, $mode, $dev, $callback->($status)
335		479
		480	[EXPERIMENTAL]
		481
336	Asynchronously create a device node (or fifo). See mknod(2): the only	482	Asynchronously create a device node (or fifo). See mknod(2).
337	portable value for C<$mode> is C<S_IFIFO> ored with permissions, and C<0>	483
338	for C<$dev>.	484	The only (POSIX-) portable way of calling this function is:
		485
		486	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		487
339		488
340	=item aio_link $srcpath, $dstpath, $callback->($status)	489	=item aio_link $srcpath, $dstpath, $callback->($status)
341		490
342	Asynchronously create a new link to the existing object at C<$srcpath> at	491	Asynchronously create a new link to the existing object at C<$srcpath> at
343	the path C<$dstpath> and call the callback with the result code.	492	the path C<$dstpath> and call the callback with the result code.
344		493
		494
345	=item aio_symlink $srcpath, $dstpath, $callback->($status)	495	=item aio_symlink $srcpath, $dstpath, $callback->($status)
346		496
347	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	497	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
348	the path C<$dstpath> and call the callback with the result code.	498	the path C<$dstpath> and call the callback with the result code.
349		499
		500
		501	=item aio_readlink $path, $callback->($link)
		502
		503	Asynchronously read the symlink specified by C<$path> and pass it to
		504	the callback. If an error occurs, nothing or undef gets passed to the
		505	callback.
		506
		507
350	=item aio_rename $srcpath, $dstpath, $callback->($status)	508	=item aio_rename $srcpath, $dstpath, $callback->($status)
351		509
352	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	510	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
353	rename(2) and call the callback with the result code.	511	rename(2) and call the callback with the result code.
354		512
		513
		514	=item aio_mkdir $pathname, $mode, $callback->($status)
		515
		516	Asynchronously mkdir (create) a directory and call the callback with
		517	the result code. C<$mode> will be modified by the umask at the time the
		518	request is executed, so do not change your umask.
		519
		520
355	=item aio_rmdir $pathname, $callback->($status)	521	=item aio_rmdir $pathname, $callback->($status)
356		522
357	Asynchronously rmdir (delete) a directory and call the callback with the	523	Asynchronously rmdir (delete) a directory and call the callback with the
358	result code.	524	result code.
		525
359		526
360	=item aio_readdir $pathname, $callback->($entries)	527	=item aio_readdir $pathname, $callback->($entries)
361		528
362	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	529	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	530	directory (i.e. opendir + readdir + closedir). The entries will not be
364	sorted, and will B<NOT> include the C<.> and C<..> entries.	531	sorted, and will B<NOT> include the C<.> and C<..> entries.
365		532
366	The callback a single argument which is either C<undef> or an array-ref	533	The callback a single argument which is either C<undef> or an array-ref
367	with the filenames.	534	with the filenames.
		535
		536
		537	=item aio_load $path, $data, $callback->($status)
		538
		539	This is a composite request that tries to fully load the given file into
		540	memory. Status is the same as with aio_read.
		541
		542	=cut
		543
		544	sub aio_load($$;$) {
		545	my ($path, undef, $cb) = @_;
		546	my $data = \$_[1];
		547
		548	my $pri = aioreq_pri;
		549	my $grp = aio_group $cb;
		550
		551	aioreq_pri $pri;
		552	add $grp aio_open $path, O_RDONLY, 0, sub {
		553	my $fh = shift
		554	or return $grp->result (-1);
		555
		556	aioreq_pri $pri;
		557	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		558	$grp->result ($_[0]);
		559	};
		560	};
		561
		562	$grp
		563	}
368		564
369	=item aio_copy $srcpath, $dstpath, $callback->($status)	565	=item aio_copy $srcpath, $dstpath, $callback->($status)
370		566
371	Try to copy the I<file> (directories not supported as either source or	567	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	568	destination) from C<$srcpath> to C<$dstpath> and call the callback with
…		…
405		601
406	# those should not normally block. should. should.	602	# those should not normally block. should. should.
407	utime $stat[8], $stat[9], $dst;	603	utime $stat[8], $stat[9], $dst;
408	chmod $stat[2] & 07777, $dst_fh;	604	chmod $stat[2] & 07777, $dst_fh;
409	chown $stat[4], $stat[5], $dst_fh;	605	chown $stat[4], $stat[5], $dst_fh;
		606
		607	aioreq_pri $pri;
410	close $dst_fh;	608	add $grp aio_close $dst_fh;
411	} else {	609	} else {
412	$grp->result (-1);	610	$grp->result (-1);
413	close $src_fh;	611	close $src_fh;
414	close $dst_fh;	612	close $dst_fh;
415		613
…		…
520	as those tend to return 0 or 1 as link counts, which disables the	718	as those tend to return 0 or 1 as link counts, which disables the
521	directory counting heuristic.	719	directory counting heuristic.
522		720
523	=cut	721	=cut
524		722
525	sub aio_scandir($$$) {	723	sub aio_scandir($$;$) {
526	my ($path, $maxreq, $cb) = @_;	724	my ($path, $maxreq, $cb) = @_;
527		725
528	my $pri = aioreq_pri;	726	my $pri = aioreq_pri;
529		727
530	my $grp = aio_group $cb;	728	my $grp = aio_group $cb;
…		…
606	};	804	};
607		805
608	$grp	806	$grp
609	}	807	}
610		808
		809	=item aio_rmtree $path, $callback->($status)
		810
		811	Delete a directory tree starting (and including) C<$path>, return the
		812	status of the final C<rmdir> only. This is a composite request that
		813	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		814	everything else.
		815
		816	=cut
		817
		818	sub aio_rmtree;
		819	sub aio_rmtree($;$) {
		820	my ($path, $cb) = @_;
		821
		822	my $pri = aioreq_pri;
		823	my $grp = aio_group $cb;
		824
		825	aioreq_pri $pri;
		826	add $grp aio_scandir $path, 0, sub {
		827	my ($dirs, $nondirs) = @_;
		828
		829	my $dirgrp = aio_group sub {
		830	add $grp aio_rmdir $path, sub {
		831	$grp->result ($_[0]);
		832	};
		833	};
		834
		835	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		836	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		837
		838	add $grp $dirgrp;
		839	};
		840
		841	$grp
		842	}
		843
		844	=item aio_sync $callback->($status)
		845
		846	Asynchronously call sync and call the callback when finished.
		847
611	=item aio_fsync $fh, $callback->($status)	848	=item aio_fsync $fh, $callback->($status)
612		849
613	Asynchronously call fsync on the given filehandle and call the callback	850	Asynchronously call fsync on the given filehandle and call the callback
614	with the fsync result code.	851	with the fsync result code.
615		852
…		…
618	Asynchronously call fdatasync on the given filehandle and call the	855	Asynchronously call fdatasync on the given filehandle and call the
619	callback with the fdatasync result code.	856	callback with the fdatasync result code.
620		857
621	If this call isn't available because your OS lacks it or it couldn't be	858	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.	859	detected, it will be emulated by calling C<fsync> instead.
		860
		861	=item aio_pathsync $path, $callback->($status)
		862
		863	This request tries to open, fsync and close the given path. This is a
		864	composite request intended tosync directories after directory operations
		865	(E.g. rename). This might not work on all operating systems or have any
		866	specific effect, but usually it makes sure that directory changes get
		867	written to disc. It works for anything that can be opened for read-only,
		868	not just directories.
		869
		870	Passes C<0> when everything went ok, and C<-1> on error.
		871
		872	=cut
		873
		874	sub aio_pathsync($;$) {
		875	my ($path, $cb) = @_;
		876
		877	my $pri = aioreq_pri;
		878	my $grp = aio_group $cb;
		879
		880	aioreq_pri $pri;
		881	add $grp aio_open $path, O_RDONLY, 0, sub {
		882	my ($fh) = @_;
		883	if ($fh) {
		884	aioreq_pri $pri;
		885	add $grp aio_fsync $fh, sub {
		886	$grp->result ($_[0]);
		887
		888	aioreq_pri $pri;
		889	add $grp aio_close $fh;
		890	};
		891	} else {
		892	$grp->result (-1);
		893	}
		894	};
		895
		896	$grp
		897	}
623		898
624	=item aio_group $callback->(...)	899	=item aio_group $callback->(...)
625		900
626	This is a very special aio request: Instead of doing something, it is a	901	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	902	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.	1039	itself. Useful when you queued a lot of events but got a result early.
765		1040
766	=item $grp->result (...)	1041	=item $grp->result (...)
767		1042
768	Set the result value(s) that will be passed to the group callback when all	1043	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	1044	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,	1045	of errno (just like calling C<errno> without an error number). By default,
771	no argument will be passed and errno is zero.	1046	no argument will be passed and errno is zero.
772		1047
773	=item $grp->errno ([$errno])	1048	=item $grp->errno ([$errno])
774		1049
…		…
827		1102
828	=back	1103	=back
829		1104
830	=head2 SUPPORT FUNCTIONS	1105	=head2 SUPPORT FUNCTIONS
831		1106
		1107	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1108
832	=over 4	1109	=over 4
833		1110
834	=item $fileno = IO::AIO::poll_fileno	1111	=item $fileno = IO::AIO::poll_fileno
835		1112
836	Return the I<request result pipe file descriptor>. This filehandle must be	1113	Return the I<request result pipe file descriptor>. This filehandle must be
…		…
840		1117
841	See C<poll_cb> for an example.	1118	See C<poll_cb> for an example.
842		1119
843	=item IO::AIO::poll_cb	1120	=item IO::AIO::poll_cb
844		1121
845	Process all outstanding events on the result pipe. You have to call this	1122	Process some outstanding events on the result pipe. You have to call this
846	regularly. Returns the number of events processed. Returns immediately	1123	regularly. Returns the number of events processed. Returns immediately
847	when no events are outstanding.	1124	when no events are outstanding. The amount of events processed depends on
		1125	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
848		1126
849	If not all requests were processed for whatever reason, the filehandle	1127	If not all requests were processed for whatever reason, the filehandle
850	will still be ready when C<poll_cb> returns.	1128	will still be ready when C<poll_cb> returns.
851		1129
852	Example: Install an Event watcher that automatically calls	1130	Example: Install an Event watcher that automatically calls
…		…
854		1132
855	Event->io (fd => IO::AIO::poll_fileno,	1133	Event->io (fd => IO::AIO::poll_fileno,
856	poll => 'r', async => 1,	1134	poll => 'r', async => 1,
857	cb => \&IO::AIO::poll_cb);	1135	cb => \&IO::AIO::poll_cb);
858		1136
859	=item IO::AIO::poll_some $max_requests	1137	=item IO::AIO::max_poll_reqs $nreqs
860		1138
861	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1139	=item IO::AIO::max_poll_time $seconds
862	at a time.
863		1140
864	Useful if you want to ensure some level of interactiveness when perl is	1141	These set the maximum number of requests (default C<0>, meaning infinity)
865	not fast enough to process all requests in time.	1142	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1143	the maximum amount of time (default C<0>, meaning infinity) spent in
		1144	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1145	of time C<poll_cb> is allowed to use).
		1146
		1147	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1148	syscall per request processed, which is not normally a problem unless your
		1149	callbacks are really really fast or your OS is really really slow (I am
		1150	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1151
		1152	Setting these is useful if you want to ensure some level of
		1153	interactiveness when perl is not fast enough to process all requests in
		1154	time.
		1155
		1156	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
866		1157
867	Example: Install an Event watcher that automatically calls	1158	Example: Install an Event watcher that automatically calls
868	IO::AIO::poll_some with low priority, to ensure that other parts of the	1159	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.	1160	program get the CPU sometimes even under high AIO load.
870		1161
		1162	# try not to spend much more than 0.1s in poll_cb
		1163	IO::AIO::max_poll_time 0.1;
		1164
		1165	# use a low priority so other tasks have priority
871	Event->io (fd => IO::AIO::poll_fileno,	1166	Event->io (fd => IO::AIO::poll_fileno,
872	poll => 'r', nice => 1,	1167	poll => 'r', nice => 1,
873	cb => sub { IO::AIO::poll_some 256 });	1168	cb => &IO::AIO::poll_cb);
874		1169
875	=item IO::AIO::poll_wait	1170	=item IO::AIO::poll_wait
876		1171
		1172	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	1173	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	1174	does a C<select> on the filehandle. This is useful if you want to
879	for some requests to finish).	1175	synchronously wait for some requests to finish).
880		1176
881	See C<nreqs> for an example.	1177	See C<nreqs> for an example.
882		1178
		1179	=item IO::AIO::poll
		1180
		1181	Waits until some requests have been handled.
		1182
		1183	Returns the number of requests processed, but is otherwise strictly
		1184	equivalent to:
		1185
		1186	IO::AIO::poll_wait, IO::AIO::poll_cb
		1187
883	=item IO::AIO::nreqs	1188	=item IO::AIO::flush
884		1189
885	Returns the number of requests currently in the ready, execute or pending	1190	Wait till all outstanding AIO requests have been handled.
886	states (i.e. for which their callback has not been invoked yet).
887		1191
888	Example: wait till there are no outstanding requests anymore:	1192	Strictly equivalent to:
889		1193
890	IO::AIO::poll_wait, IO::AIO::poll_cb	1194	IO::AIO::poll_wait, IO::AIO::poll_cb
891	while IO::AIO::nreqs;	1195	while IO::AIO::nreqs;
892		1196
893	=item IO::AIO::nready	1197	=back
894		1198
895	Returns the number of requests currently in the ready state (not yet	1199	=head3 CONTROLLING THE NUMBER OF THREADS
896	executed).
897		1200
898	=item IO::AIO::npending	1201	=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		1202
921	=item IO::AIO::min_parallel $nthreads	1203	=item IO::AIO::min_parallel $nthreads
922		1204
923	Set the minimum number of AIO threads to C<$nthreads>. The current	1205	Set the minimum number of AIO threads to C<$nthreads>. The current
924	default is C<8>, which means eight asynchronous operations can execute	1206	default is C<8>, which means eight asynchronous operations can execute
925	concurrently at any one time (the number of outstanding requests,	1207	concurrently at any one time (the number of outstanding requests,
926	however, is unlimited).	1208	however, is unlimited).
927		1209
928	IO::AIO starts threads only on demand, when an AIO request is queued and	1210	IO::AIO starts threads only on demand, when an AIO request is queued and
929	no free thread exists.	1211	no free thread exists. Please note that queueing up a hundred requests can
		1212	create demand for a hundred threads, even if it turns out that everything
		1213	is in the cache and could have been processed faster by a single thread.
930		1214
931	It is recommended to keep the number of threads relatively low, as some	1215	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	1216	Linux kernel versions will scale negatively with the number of threads
933	(higher parallelity => MUCH higher latency). With current Linux 2.6	1217	(higher parallelity => MUCH higher latency). With current Linux 2.6
934	versions, 4-32 threads should be fine.	1218	versions, 4-32 threads should be fine.
…		…
948	This module automatically runs C<max_parallel 0> at program end, to ensure	1232	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.	1233	that all threads are killed and that there are no outstanding requests.
950		1234
951	Under normal circumstances you don't need to call this function.	1235	Under normal circumstances you don't need to call this function.
952		1236
		1237	=item IO::AIO::max_idle $nthreads
		1238
		1239	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1240	threads that did not get a request to process within 10 seconds). That
		1241	means if a thread becomes idle while C<$nthreads> other threads are also
		1242	idle, it will free its resources and exit.
		1243
		1244	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1245	to allow for extremely high load situations, but want to free resources
		1246	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1247
		1248	The default is probably ok in most situations, especially if thread
		1249	creation is fast. If thread creation is very slow on your system you might
		1250	want to use larger values.
		1251
953	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1252	=item IO::AIO::max_outstanding $maxreqs
954		1253
955	This is a very bad function to use in interactive programs because it	1254	This is a very bad function to use in interactive programs because it
956	blocks, and a bad way to reduce concurrency because it is inexact: Better	1255	blocks, and a bad way to reduce concurrency because it is inexact: Better
957	use an C<aio_group> together with a feed callback.	1256	use an C<aio_group> together with a feed callback.
958		1257
959	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1258	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	1259	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>)	1260	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.	1261	function will block until the limit is no longer exceeded.
963		1262
964	The default value is very large, so there is no practical limit on the	1263	The default value is very large, so there is no practical limit on the
965	number of outstanding requests.	1264	number of outstanding requests.
966		1265
967	You can still queue as many requests as you want. Therefore,	1266	You can still queue as many requests as you want. Therefore,
968	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1267	C<max_outstanding> is mainly useful in simple scripts (with low values) or
969	as a stop gap to shield against fatal memory overflow (with large values).	1268	as a stop gap to shield against fatal memory overflow (with large values).
970		1269
971	=back	1270	=back
972		1271
		1272	=head3 STATISTICAL INFORMATION
		1273
		1274	=over
		1275
		1276	=item IO::AIO::nreqs
		1277
		1278	Returns the number of requests currently in the ready, execute or pending
		1279	states (i.e. for which their callback has not been invoked yet).
		1280
		1281	Example: wait till there are no outstanding requests anymore:
		1282
		1283	IO::AIO::poll_wait, IO::AIO::poll_cb
		1284	while IO::AIO::nreqs;
		1285
		1286	=item IO::AIO::nready
		1287
		1288	Returns the number of requests currently in the ready state (not yet
		1289	executed).
		1290
		1291	=item IO::AIO::npending
		1292
		1293	Returns the number of requests currently in the pending state (executed,
		1294	but not yet processed by poll_cb).
		1295
		1296	=back
		1297
973	=cut	1298	=cut
974		1299
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;	1300	min_parallel 8;
992		1301
993	END {	1302	END { flush }
994	flush;
995	};
996		1303
997	1;	1304	1;
998		1305
999	=head2 FORK BEHAVIOUR	1306	=head2 FORK BEHAVIOUR
1000		1307
…		…
1020	bytes of memory. In addition, stat requests need a stat buffer (possibly	1327	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	1328	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	1329	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.	1330	will consume memory till the request has entered the done state.
1024		1331
1025	This is now awfully much, so queuing lots of requests is not usually a	1332	This is not awfully much, so queuing lots of requests is not usually a
1026	problem.	1333	problem.
1027		1334
1028	Per-thread usage:	1335	Per-thread usage:
1029		1336
1030	In the execution phase, some aio requests require more memory for	1337	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 1.124 by root, Sat May 10 19:25:33 2008 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 1.124 by root, Sat May 10 19:25:33 2008 UTC