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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.54 by root, Sun Oct 22 00:19:05 2006 UTC vs.
Revision 1.89 by root, Sun Oct 29 11:03:18 2006 UTC

…		…
15		15
16	aio_read $fh, 30000, 1024, $buffer, 0, sub {	16	aio_read $fh, 30000, 1024, $buffer, 0, sub {
17	$_[0] > 0 or die "read error: $!";	17	$_[0] > 0 or die "read error: $!";
18	};	18	};
19		19
20	use IO::AIO 2; # version has aio objects	20	# version 2+ has request and group objects
		21	use IO::AIO 2;
21		22
		23	aioreq_pri 4; # give next request a very high priority
22	my $req = aio_unlink "/tmp/file", sub { };	24	my $req = aio_unlink "/tmp/file", sub { };
23	$req->cancel; # cancel request if still in queue	25	$req->cancel; # cancel request if still in queue
24		26
25	# AnyEvent	27	my $grp = aio_group sub { print "all stats done\n" };
		28	add $grp aio_stat "..." for ...;
		29
		30	# AnyEvent integration
26	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";	31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
27	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });	32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
28		33
29	# Event	34	# Event integration
30	Event->io (fd => IO::AIO::poll_fileno,	35	Event->io (fd => IO::AIO::poll_fileno,
31	poll => 'r',	36	poll => 'r',
32	cb => \&IO::AIO::poll_cb);	37	cb => \&IO::AIO::poll_cb);
33		38
34	# Glib/Gtk2	39	# Glib/Gtk2 integration
35	add_watch Glib::IO IO::AIO::poll_fileno,	40	add_watch Glib::IO IO::AIO::poll_fileno,
36	in => sub { IO::AIO::poll_cb; 1 };	41	in => sub { IO::AIO::poll_cb; 1 };
37		42
38	# Tk	43	# Tk integration
39	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",	44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
40	readable => \&IO::AIO::poll_cb);	45	readable => \&IO::AIO::poll_cb);
41		46
42	# Danga::Socket	47	# Danga::Socket integration
43	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
44	\&IO::AIO::poll_cb);	49	\&IO::AIO::poll_cb);
45		50
46
47	=head1 DESCRIPTION	51	=head1 DESCRIPTION
48		52
49	This module implements asynchronous I/O using whatever means your	53	This module implements asynchronous I/O using whatever means your
50	operating system supports.	54	operating system supports.
51		55
		56	Asynchronous means that operations that can normally block your program
		57	(e.g. reading from disk) will be done asynchronously: the operation
		58	will still block, but you can do something else in the meantime. This
		59	is extremely useful for programs that need to stay interactive even
		60	when doing heavy I/O (GUI programs, high performance network servers
		61	etc.), but can also be used to easily do operations in parallel that are
		62	normally done sequentially, e.g. stat'ing many files, which is much faster
		63	on a RAID volume or over NFS when you do a number of stat operations
		64	concurrently.
		65
		66	While this works on all types of file descriptors (for example sockets),
		67	using these functions on file descriptors that support nonblocking
		68	operation (again, sockets, pipes etc.) is very inefficient. Use an event
		69	loop for that (such as the L<Event\|Event> module): IO::AIO will naturally
		70	fit into such an event loop itself.
		71
52	Currently, a number of threads are started that execute your read/writes	72	In this version, a number of threads are started that execute your
53	and signal their completion. You don't need thread support in your libc or	73	requests and signal their completion. You don't need thread support
54	perl, and the threads created by this module will not be visible to the	74	in perl, and the threads created by this module will not be visible
55	pthreads library. In the future, this module might make use of the native	75	to perl. In the future, this module might make use of the native aio
56	aio functions available on many operating systems. However, they are often	76	functions available on many operating systems. However, they are often
57	not well-supported (Linux doesn't allow them on normal files currently,	77	not well-supported or restricted (GNU/Linux doesn't allow them on normal
58	for example), and they would only support aio_read and aio_write, so the	78	files currently, for example), and they would only support aio_read and
59	remaining functionality would have to be implemented using threads anyway.	79	aio_write, so the remaining functionality would have to be implemented
		80	using threads anyway.
60		81
61	Although the module will work with in the presence of other threads, it is	82	Although the module will work with in the presence of other (Perl-)
62	currently not reentrant, so use appropriate locking yourself, always call	83	threads, it is currently not reentrant in any way, so use appropriate
63	C<poll_cb> from within the same thread, or never call C<poll_cb> (or other	84	locking yourself, always call C<poll_cb> from within the same thread, or
64	C<aio_> functions) recursively.	85	never call C<poll_cb> (or other C<aio_> functions) recursively.
		86
		87	=head2 EXAMPLE
		88
		89	This is a simple example that uses the Event module and loads
		90	F</etc/passwd> asynchronously:
		91
		92	use Fcntl;
		93	use Event;
		94	use IO::AIO;
		95
		96	# register the IO::AIO callback with Event
		97	Event->io (fd => IO::AIO::poll_fileno,
		98	poll => 'r',
		99	cb => \&IO::AIO::poll_cb);
		100
		101	# queue the request to open /etc/passwd
		102	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		103	my $fh = $_[0]
		104	or die "error while opening: $!";
		105
		106	# stat'ing filehandles is generally non-blocking
		107	my $size = -s $fh;
		108
		109	# queue a request to read the file
		110	my $contents;
		111	aio_read $fh, 0, $size, $contents, 0, sub {
		112	$_[0] == $size
		113	or die "short read: $!";
		114
		115	close $fh;
		116
		117	# file contents now in $contents
		118	print $contents;
		119
		120	# exit event loop and program
		121	Event::unloop;
		122	};
		123	};
		124
		125	# possibly queue up other requests, or open GUI windows,
		126	# check for sockets etc. etc.
		127
		128	# process events as long as there are some:
		129	Event::loop;
		130
		131	=head1 REQUEST ANATOMY AND LIFETIME
		132
		133	Every C<aio_*> function creates a request. which is a C data structure not
		134	directly visible to Perl.
		135
		136	If called in non-void context, every request function returns a Perl
		137	object representing the request. In void context, nothing is returned,
		138	which saves a bit of memory.
		139
		140	The perl object is a fairly standard ref-to-hash object. The hash contents
		141	are not used by IO::AIO so you are free to store anything you like in it.
		142
		143	During their existance, aio requests travel through the following states,
		144	in order:
		145
		146	=over 4
		147
		148	=item ready
		149
		150	Immediately after a request is created it is put into the ready state,
		151	waiting for a thread to execute it.
		152
		153	=item execute
		154
		155	A thread has accepted the request for processing and is currently
		156	executing it (e.g. blocking in read).
		157
		158	=item pending
		159
		160	The request has been executed and is waiting for result processing.
		161
		162	While request submission and execution is fully asynchronous, result
		163	processing is not and relies on the perl interpreter calling C<poll_cb>
		164	(or another function with the same effect).
		165
		166	=item result
		167
		168	The request results are processed synchronously by C<poll_cb>.
		169
		170	The C<poll_cb> function will process all outstanding aio requests by
		171	calling their callbacks, freeing memory associated with them and managing
		172	any groups they are contained in.
		173
		174	=item done
		175
		176	Request has reached the end of its lifetime and holds no resources anymore
		177	(except possibly for the Perl object, but its connection to the actual
		178	aio request is severed and calling its methods will either do nothing or
		179	result in a runtime error).
		180
		181	=back
65		182
66	=cut	183	=cut
67		184
68	package IO::AIO;	185	package IO::AIO;
69		186
…		…
71	use strict 'vars';	188	use strict 'vars';
72		189
73	use base 'Exporter';	190	use base 'Exporter';
74		191
75	BEGIN {	192	BEGIN {
76	our $VERSION = '1.99';	193	our $VERSION = '2.1';
77		194
78	our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	195	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
79	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	196	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
80	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	197	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
81	aio_group);	198	aio_copy aio_group aio_nop aio_mknod);
82	our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	199	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
		200	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
		201	min_parallel max_parallel max_idle
		202	nreqs nready npending nthreads
		203	max_poll_time max_poll_reqs);
83		204
84	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	205	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
85		206
86	require XSLoader;	207	require XSLoader;
87	XSLoader::load ("IO::AIO", $VERSION);	208	XSLoader::load ("IO::AIO", $VERSION);
88	}	209	}
89		210
90	=head1 FUNCTIONS	211	=head1 FUNCTIONS
91		212
92	=head2 AIO FUNCTIONS	213	=head2 AIO REQUEST FUNCTIONS
93		214
94	All the C<aio_*> calls are more or less thin wrappers around the syscall	215	All the C<aio_*> calls are more or less thin wrappers around the syscall
95	with the same name (sans C<aio_>). The arguments are similar or identical,	216	with the same name (sans C<aio_>). The arguments are similar or identical,
96	and they all accept an additional (and optional) C<$callback> argument	217	and they all accept an additional (and optional) C<$callback> argument
97	which must be a code reference. This code reference will get called with	218	which must be a code reference. This code reference will get called with
…		…
100	syscall has been executed asynchronously.	221	syscall has been executed asynchronously.
101		222
102	All functions expecting a filehandle keep a copy of the filehandle	223	All functions expecting a filehandle keep a copy of the filehandle
103	internally until the request has finished.	224	internally until the request has finished.
104		225
105	All non-composite requests (requests that are not broken down into
106	multiple requests) return objects of type L<IO::AIO::REQ> that allow	226	All functions return request objects of type L<IO::AIO::REQ> that allow
107	further manipulation of running requests.	227	further manipulation of those requests while they are in-flight.
108		228
109	The pathnames you pass to these routines I<must> be absolute and	229	The pathnames you pass to these routines I<must> be absolute and
110	encoded in byte form. The reason for the former is that at the time the	230	encoded as octets. The reason for the former is that at the time the
111	request is being executed, the current working directory could have	231	request is being executed, the current working directory could have
112	changed. Alternatively, you can make sure that you never change the	232	changed. Alternatively, you can make sure that you never change the
113	current working directory.	233	current working directory anywhere in the program and then use relative
		234	paths.
114		235
115	To encode pathnames to byte form, either make sure you either: a)	236	To encode pathnames as octets, either make sure you either: a) always pass
116	always pass in filenames you got from outside (command line, readdir	237	in filenames you got from outside (command line, readdir etc.) without
117	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	238	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
118	your pathnames to the locale (or other) encoding in effect in the user	239	your pathnames to the locale (or other) encoding in effect in the user
119	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	240	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
120	use something else.	241	use something else to ensure your scalar has the correct contents.
		242
		243	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		244	handles correctly wether it is set or not.
121		245
122	=over 4	246	=over 4
		247
		248	=item $prev_pri = aioreq_pri [$pri]
		249
		250	Returns the priority value that would be used for the next request and, if
		251	C<$pri> is given, sets the priority for the next aio request.
		252
		253	The default priority is C<0>, the minimum and maximum priorities are C<-4>
		254	and C<4>, respectively. Requests with higher priority will be serviced
		255	first.
		256
		257	The priority will be reset to C<0> after each call to one of the C<aio_*>
		258	functions.
		259
		260	Example: open a file with low priority, then read something from it with
		261	higher priority so the read request is serviced before other low priority
		262	open requests (potentially spamming the cache):
		263
		264	aioreq_pri -3;
		265	aio_open ..., sub {
		266	return unless $_[0];
		267
		268	aioreq_pri -2;
		269	aio_read $_[0], ..., sub {
		270	...
		271	};
		272	};
		273
		274	=item aioreq_nice $pri_adjust
		275
		276	Similar to C<aioreq_pri>, but subtracts the given value from the current
		277	priority, so the effect is cumulative.
123		278
124	=item aio_open $pathname, $flags, $mode, $callback->($fh)	279	=item aio_open $pathname, $flags, $mode, $callback->($fh)
125		280
126	Asynchronously open or create a file and call the callback with a newly	281	Asynchronously open or create a file and call the callback with a newly
127	created filehandle for the file.	282	created filehandle for the file.
…		…
177		332
178	aio_read $fh, 7, 15, $buffer, 0, sub {	333	aio_read $fh, 7, 15, $buffer, 0, sub {
179	$_[0] > 0 or die "read error: $!";	334	$_[0] > 0 or die "read error: $!";
180	print "read $_[0] bytes: <$buffer>\n";	335	print "read $_[0] bytes: <$buffer>\n";
181	};	336	};
182
183	=item aio_move $srcpath, $dstpath, $callback->($status)
184
185	Try to move the I<file> (directories not supported as either source or
186	destination) from C<$srcpath> to C<$dstpath> and call the callback with
187	the C<0> (error) or C<-1> ok.
188
189	This is a composite request that tries to rename(2) the file first. If
190	rename files with C<EXDEV>, it creates the destination file with mode 0200
191	and copies the contents of the source file into it using C<aio_sendfile>,
192	followed by restoring atime, mtime, access mode and uid/gid, in that
193	order, and unlinking the C<$srcpath>.
194
195	If an error occurs, the partial destination file will be unlinked, if
196	possible, except when setting atime, mtime, access mode and uid/gid, where
197	errors are being ignored.
198
199	=cut
200
201	sub aio_move($$$) {
202	my ($src, $dst, $cb) = @_;
203
204	aio_rename $src, $dst, sub {
205	if ($_[0] && $! == EXDEV) {
206	aio_open $src, O_RDONLY, 0, sub {
207	if (my $src_fh = $_[0]) {
208	my @stat = stat $src_fh;
209
210	aio_open $dst, O_WRONLY, 0200, sub {
211	if (my $dst_fh = $_[0]) {
212	aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
213	close $src_fh;
214
215	if ($_[0] == $stat[7]) {
216	utime $stat[8], $stat[9], $dst;
217	chmod $stat[2] & 07777, $dst_fh;
218	chown $stat[4], $stat[5], $dst_fh;
219	close $dst_fh;
220
221	aio_unlink $src, sub {
222	$cb->($_[0]);
223	};
224	} else {
225	my $errno = $!;
226	aio_unlink $dst, sub {
227	$! = $errno;
228	$cb->(-1);
229	};
230	}
231	};
232	} else {
233	$cb->(-1);
234	}
235	},
236
237	} else {
238	$cb->(-1);
239	}
240	};
241	} else {
242	$cb->($_[0]);
243	}
244	};
245	}
246		337
247	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	338	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
248		339
249	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	340	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
250	reading at byte offset C<$in_offset>, and starts writing at the current	341	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
306	=item aio_unlink $pathname, $callback->($status)	397	=item aio_unlink $pathname, $callback->($status)
307		398
308	Asynchronously unlink (delete) a file and call the callback with the	399	Asynchronously unlink (delete) a file and call the callback with the
309	result code.	400	result code.
310		401
		402	=item aio_mknod $path, $mode, $dev, $callback->($status)
		403
		404	[EXPERIMENTAL]
		405
		406	Asynchronously create a device node (or fifo). See mknod(2).
		407
		408	The only (POSIX-) portable way of calling this function is:
		409
		410	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		411
311	=item aio_link $srcpath, $dstpath, $callback->($status)	412	=item aio_link $srcpath, $dstpath, $callback->($status)
312		413
313	Asynchronously create a new link to the existing object at C<$srcpath> at	414	Asynchronously create a new link to the existing object at C<$srcpath> at
314	the path C<$dstpath> and call the callback with the result code.	415	the path C<$dstpath> and call the callback with the result code.
315		416
…		…
335	sorted, and will B<NOT> include the C<.> and C<..> entries.	436	sorted, and will B<NOT> include the C<.> and C<..> entries.
336		437
337	The callback a single argument which is either C<undef> or an array-ref	438	The callback a single argument which is either C<undef> or an array-ref
338	with the filenames.	439	with the filenames.
339		440
		441	=item aio_copy $srcpath, $dstpath, $callback->($status)
		442
		443	Try to copy the I<file> (directories not supported as either source or
		444	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		445	the C<0> (error) or C<-1> ok.
		446
		447	This is a composite request that it creates the destination file with
		448	mode 0200 and copies the contents of the source file into it using
		449	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		450	uid/gid, in that order.
		451
		452	If an error occurs, the partial destination file will be unlinked, if
		453	possible, except when setting atime, mtime, access mode and uid/gid, where
		454	errors are being ignored.
		455
		456	=cut
		457
		458	sub aio_copy($$;$) {
		459	my ($src, $dst, $cb) = @_;
		460
		461	my $pri = aioreq_pri;
		462	my $grp = aio_group $cb;
		463
		464	aioreq_pri $pri;
		465	add $grp aio_open $src, O_RDONLY, 0, sub {
		466	if (my $src_fh = $_[0]) {
		467	my @stat = stat $src_fh;
		468
		469	aioreq_pri $pri;
		470	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		471	if (my $dst_fh = $_[0]) {
		472	aioreq_pri $pri;
		473	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		474	if ($_[0] == $stat[7]) {
		475	$grp->result (0);
		476	close $src_fh;
		477
		478	# those should not normally block. should. should.
		479	utime $stat[8], $stat[9], $dst;
		480	chmod $stat[2] & 07777, $dst_fh;
		481	chown $stat[4], $stat[5], $dst_fh;
		482	close $dst_fh;
		483	} else {
		484	$grp->result (-1);
		485	close $src_fh;
		486	close $dst_fh;
		487
		488	aioreq $pri;
		489	add $grp aio_unlink $dst;
		490	}
		491	};
		492	} else {
		493	$grp->result (-1);
		494	}
		495	},
		496
		497	} else {
		498	$grp->result (-1);
		499	}
		500	};
		501
		502	$grp
		503	}
		504
		505	=item aio_move $srcpath, $dstpath, $callback->($status)
		506
		507	Try to move the I<file> (directories not supported as either source or
		508	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		509	the C<0> (error) or C<-1> ok.
		510
		511	This is a composite request that tries to rename(2) the file first. If
		512	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		513	that is successful, unlinking the C<$srcpath>.
		514
		515	=cut
		516
		517	sub aio_move($$;$) {
		518	my ($src, $dst, $cb) = @_;
		519
		520	my $pri = aioreq_pri;
		521	my $grp = aio_group $cb;
		522
		523	aioreq_pri $pri;
		524	add $grp aio_rename $src, $dst, sub {
		525	if ($_[0] && $! == EXDEV) {
		526	aioreq_pri $pri;
		527	add $grp aio_copy $src, $dst, sub {
		528	$grp->result ($_[0]);
		529
		530	if (!$_[0]) {
		531	aioreq_pri $pri;
		532	add $grp aio_unlink $src;
		533	}
		534	};
		535	} else {
		536	$grp->result ($_[0]);
		537	}
		538	};
		539
		540	$grp
		541	}
		542
340	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	543	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
341		544
342	Scans a directory (similar to C<aio_readdir>) but additionally tries to	545	Scans a directory (similar to C<aio_readdir>) but additionally tries to
343	separate the entries of directory C<$path> into two sets of names, ones	546	efficiently separate the entries of directory C<$path> into two sets of
344	you can recurse into (directories or links to them), and ones you cannot	547	names, directories you can recurse into (directories), and ones you cannot
345	recurse into (everything else).	548	recurse into (everything else, including symlinks to directories).
346		549
347	C<aio_scandir> is a composite request that consists of many sub	550	C<aio_scandir> is a composite request that creates of many sub requests_
348	requests. C<$maxreq> specifies the maximum number of outstanding aio	551	C<$maxreq> specifies the maximum number of outstanding aio requests that
349	requests that this function generates. If it is C<< <= 0 >>, then a	552	this function generates. If it is C<< <= 0 >>, then a suitable default
350	suitable default will be chosen (currently 8).	553	will be chosen (currently 4).
351		554
352	On error, the callback is called without arguments, otherwise it receives	555	On error, the callback is called without arguments, otherwise it receives
353	two array-refs with path-relative entry names.	556	two array-refs with path-relative entry names.
354		557
355	Example:	558	Example:
…		…
392	=cut	595	=cut
393		596
394	sub aio_scandir($$$) {	597	sub aio_scandir($$$) {
395	my ($path, $maxreq, $cb) = @_;	598	my ($path, $maxreq, $cb) = @_;
396		599
		600	my $pri = aioreq_pri;
		601
		602	my $grp = aio_group $cb;
		603
397	$maxreq = 8 if $maxreq <= 0;	604	$maxreq = 4 if $maxreq <= 0;
398		605
399	# stat once	606	# stat once
		607	aioreq_pri $pri;
400	aio_stat $path, sub {	608	add $grp aio_stat $path, sub {
401	return $cb->() if $_[0];	609	return $grp->result () if $_[0];
402	my $now = time;	610	my $now = time;
403	my $hash1 = join ":", (stat _)[0,1,3,7,9];	611	my $hash1 = join ":", (stat _)[0,1,3,7,9];
404		612
405	# read the directory entries	613	# read the directory entries
		614	aioreq_pri $pri;
406	aio_readdir $path, sub {	615	add $grp aio_readdir $path, sub {
407	my $entries = shift	616	my $entries = shift
408	or return $cb->();	617	or return $grp->result ();
409		618
410	# stat the dir another time	619	# stat the dir another time
		620	aioreq_pri $pri;
411	aio_stat $path, sub {	621	add $grp aio_stat $path, sub {
412	my $hash2 = join ":", (stat _)[0,1,3,7,9];	622	my $hash2 = join ":", (stat _)[0,1,3,7,9];
413		623
414	my $ndirs;	624	my $ndirs;
415		625
416	# take the slow route if anything looks fishy	626	# take the slow route if anything looks fishy
…		…
418	$ndirs = -1;	628	$ndirs = -1;
419	} else {	629	} else {
420	# if nlink == 2, we are finished	630	# if nlink == 2, we are finished
421	# on non-posix-fs's, we rely on nlink < 2	631	# on non-posix-fs's, we rely on nlink < 2
422	$ndirs = (stat _)[3] - 2	632	$ndirs = (stat _)[3] - 2
423	or return $cb->([], $entries);	633	or return $grp->result ([], $entries);
424	}	634	}
425		635
426	# sort into likely dirs and likely nondirs	636	# sort into likely dirs and likely nondirs
427	# dirs == files without ".", short entries first	637	# dirs == files without ".", short entries first
428	$entries = [map $_->[0],	638	$entries = [map $_->[0],
…		…
430	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	640	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
431	@$entries];	641	@$entries];
432		642
433	my (@dirs, @nondirs);	643	my (@dirs, @nondirs);
434		644
435	my ($statcb, $schedcb);	645	my $statgrp = add $grp aio_group sub {
436	my $nreq = 0;	646	$grp->result (\@dirs, \@nondirs);
		647	};
437		648
438	$schedcb = sub {	649	limit $statgrp $maxreq;
439	if (@$entries) {	650	feed $statgrp sub {
440	if ($nreq < $maxreq) {	651	return unless @$entries;
441	my $ent = pop @$entries;	652	my $entry = pop @$entries;
		653
		654	aioreq_pri $pri;
		655	add $statgrp aio_stat "$path/$entry/.", sub {
		656	if ($_[0] < 0) {
		657	push @nondirs, $entry;
		658	} else {
		659	# need to check for real directory
		660	aioreq_pri $pri;
		661	add $statgrp aio_lstat "$path/$entry", sub {
		662	if (-d _) {
		663	push @dirs, $entry;
		664
		665	unless (--$ndirs) {
		666	push @nondirs, @$entries;
		667	feed $statgrp;
		668	}
		669	} else {
		670	push @nondirs, $entry;
		671	}
442	$nreq++;	672	}
443	aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
444	}	673	}
445	} elsif (!$nreq) {
446	# finished
447	undef $statcb;
448	undef $schedcb;
449	$cb->(\@dirs, \@nondirs) if $cb;
450	undef $cb;
451	}	674	};
452	};	675	};
453	$statcb = sub {
454	my ($status, $entry) = @_;
455
456	if ($status < 0) {
457	$nreq--;
458	push @nondirs, $entry;
459	&$schedcb;
460	} else {
461	# need to check for real directory
462	aio_lstat "$path/$entry", sub {
463	$nreq--;
464
465	if (-d _) {
466	push @dirs, $entry;
467
468	if (!--$ndirs) {
469	push @nondirs, @$entries;
470	$entries = [];
471	}
472	} else {
473	push @nondirs, $entry;
474	}
475
476	&$schedcb;
477	}
478	}
479	};
480
481	&$schedcb while @$entries && $nreq < $maxreq;
482	};	676	};
483	};	677	};
484	};	678	};
		679
		680	$grp
485	}	681	}
486		682
487	=item aio_fsync $fh, $callback->($status)	683	=item aio_fsync $fh, $callback->($status)
488		684
489	Asynchronously call fsync on the given filehandle and call the callback	685	Asynchronously call fsync on the given filehandle and call the callback
…		…
495	callback with the fdatasync result code.	691	callback with the fdatasync result code.
496		692
497	If this call isn't available because your OS lacks it or it couldn't be	693	If this call isn't available because your OS lacks it or it couldn't be
498	detected, it will be emulated by calling C<fsync> instead.	694	detected, it will be emulated by calling C<fsync> instead.
499		695
500	=item aio_group $callback->()	696	=item aio_group $callback->(...)
501		697
		698	This is a very special aio request: Instead of doing something, it is a
		699	container for other aio requests, which is useful if you want to bundle
		700	many requests into a single, composite, request with a definite callback
		701	and the ability to cancel the whole request with its subrequests.
		702
		703	Returns an object of class L<IO::AIO::GRP>. See its documentation below
		704	for more info.
		705
		706	Example:
		707
		708	my $grp = aio_group sub {
		709	print "all stats done\n";
		710	};
		711
		712	add $grp
		713	(aio_stat ...),
		714	(aio_stat ...),
		715	...;
		716
		717	=item aio_nop $callback->()
		718
		719	This is a special request - it does nothing in itself and is only used for
		720	side effects, such as when you want to add a dummy request to a group so
		721	that finishing the requests in the group depends on executing the given
		722	code.
		723
		724	While this request does nothing, it still goes through the execution
		725	phase and still requires a worker thread. Thus, the callback will not
		726	be executed immediately but only after other requests in the queue have
		727	entered their execution phase. This can be used to measure request
		728	latency.
		729
502	=item aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	730	=item IO::AIO::aio_busy $fractional_seconds, $callback->() NOT EXPORTED
503		731
504	Mainly used for debugging and benchmarking, this aio request puts one of	732	Mainly used for debugging and benchmarking, this aio request puts one of
505	the request workers to sleep for the given time.	733	the request workers to sleep for the given time.
506		734
		735	While it is theoretically handy to have simple I/O scheduling requests
		736	like sleep and file handle readable/writable, the overhead this creates is
		737	immense (it blocks a thread for a long time) so do not use this function
		738	except to put your application under artificial I/O pressure.
		739
507	=back	740	=back
508		741
509	=head2 IO::AIO::REQ CLASS	742	=head2 IO::AIO::REQ CLASS
510		743
511	All non-aggregate C<aio_*> functions return an object of this class when	744	All non-aggregate C<aio_*> functions return an object of this class when
512	called in non-void context.	745	called in non-void context.
513		746
514	A request always moves through the following five states in its lifetime,
515	in order: B<ready> (request has been created, but has not been executed
516	yet), B<execute> (request is currently being executed), B<pending>
517	(request has been executed but callback has not been called yet),
518	B<result> (results are being processed synchronously, includes calling the
519	callback) and B<done> (request has reached the end of its lifetime and
520	holds no resources anymore).
521
522	=over 4	747	=over 4
523		748
524	=item $req->cancel	749	=item cancel $req
525		750
526	Cancels the request, if possible. Has the effect of skipping execution	751	Cancels the request, if possible. Has the effect of skipping execution
527	when entering the B<execute> state and skipping calling the callback when	752	when entering the B<execute> state and skipping calling the callback when
528	entering the the B<result> state, but will leave the request otherwise	753	entering the the B<result> state, but will leave the request otherwise
529	untouched. That means that requests that currently execute will not be	754	untouched. That means that requests that currently execute will not be
530	stopped and resources held by the request will not be freed prematurely.	755	stopped and resources held by the request will not be freed prematurely.
531		756
		757	=item cb $req $callback->(...)
		758
		759	Replace (or simply set) the callback registered to the request.
		760
532	=back	761	=back
533		762
		763	=head2 IO::AIO::GRP CLASS
		764
		765	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to
		766	objects of this class, too.
		767
		768	A IO::AIO::GRP object is a special request that can contain multiple other
		769	aio requests.
		770
		771	You create one by calling the C<aio_group> constructing function with a
		772	callback that will be called when all contained requests have entered the
		773	C<done> state:
		774
		775	my $grp = aio_group sub {
		776	print "all requests are done\n";
		777	};
		778
		779	You add requests by calling the C<add> method with one or more
		780	C<IO::AIO::REQ> objects:
		781
		782	$grp->add (aio_unlink "...");
		783
		784	add $grp aio_stat "...", sub {
		785	$_[0] or return $grp->result ("error");
		786
		787	# add another request dynamically, if first succeeded
		788	add $grp aio_open "...", sub {
		789	$grp->result ("ok");
		790	};
		791	};
		792
		793	This makes it very easy to create composite requests (see the source of
		794	C<aio_move> for an application) that work and feel like simple requests.
		795
		796	=over 4
		797
		798	=item * The IO::AIO::GRP objects will be cleaned up during calls to
		799	C<IO::AIO::poll_cb>, just like any other request.
		800
		801	=item * They can be canceled like any other request. Canceling will cancel not
		802	only the request itself, but also all requests it contains.
		803
		804	=item * They can also can also be added to other IO::AIO::GRP objects.
		805
		806	=item * You must not add requests to a group from within the group callback (or
		807	any later time).
		808
		809	=back
		810
		811	Their lifetime, simplified, looks like this: when they are empty, they
		812	will finish very quickly. If they contain only requests that are in the
		813	C<done> state, they will also finish. Otherwise they will continue to
		814	exist.
		815
		816	That means after creating a group you have some time to add requests. And
		817	in the callbacks of those requests, you can add further requests to the
		818	group. And only when all those requests have finished will the the group
		819	itself finish.
		820
		821	=over 4
		822
		823	=item add $grp ...
		824
		825	=item $grp->add (...)
		826
		827	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
		828	be added, including other groups, as long as you do not create circular
		829	dependencies.
		830
		831	Returns all its arguments.
		832
		833	=item $grp->cancel_subs
		834
		835	Cancel all subrequests and clears any feeder, but not the group request
		836	itself. Useful when you queued a lot of events but got a result early.
		837
		838	=item $grp->result (...)
		839
		840	Set the result value(s) that will be passed to the group callback when all
		841	subrequests have finished and set thre groups errno to the current value
		842	of errno (just like calling C<errno> without an error number). By default,
		843	no argument will be passed and errno is zero.
		844
		845	=item $grp->errno ([$errno])
		846
		847	Sets the group errno value to C<$errno>, or the current value of errno
		848	when the argument is missing.
		849
		850	Every aio request has an associated errno value that is restored when
		851	the callback is invoked. This method lets you change this value from its
		852	default (0).
		853
		854	Calling C<result> will also set errno, so make sure you either set C<$!>
		855	before the call to C<result>, or call c<errno> after it.
		856
		857	=item feed $grp $callback->($grp)
		858
		859	Sets a feeder/generator on this group: every group can have an attached
		860	generator that generates requests if idle. The idea behind this is that,
		861	although you could just queue as many requests as you want in a group,
		862	this might starve other requests for a potentially long time. For
		863	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
		864	requests, delaying any later requests for a long time.
		865
		866	To avoid this, and allow incremental generation of requests, you can
		867	instead a group and set a feeder on it that generates those requests. The
		868	feed callback will be called whenever there are few enough (see C<limit>,
		869	below) requests active in the group itself and is expected to queue more
		870	requests.
		871
		872	The feed callback can queue as many requests as it likes (i.e. C<add> does
		873	not impose any limits).
		874
		875	If the feed does not queue more requests when called, it will be
		876	automatically removed from the group.
		877
		878	If the feed limit is C<0>, it will be set to C<2> automatically.
		879
		880	Example:
		881
		882	# stat all files in @files, but only ever use four aio requests concurrently:
		883
		884	my $grp = aio_group sub { print "finished\n" };
		885	limit $grp 4;
		886	feed $grp sub {
		887	my $file = pop @files
		888	or return;
		889
		890	add $grp aio_stat $file, sub { ... };
		891	};
		892
		893	=item limit $grp $num
		894
		895	Sets the feeder limit for the group: The feeder will be called whenever
		896	the group contains less than this many requests.
		897
		898	Setting the limit to C<0> will pause the feeding process.
		899
		900	=back
		901
534	=head2 SUPPORT FUNCTIONS	902	=head2 SUPPORT FUNCTIONS
		903
		904	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
535		905
536	=over 4	906	=over 4
537		907
538	=item $fileno = IO::AIO::poll_fileno	908	=item $fileno = IO::AIO::poll_fileno
539		909
…		…
544		914
545	See C<poll_cb> for an example.	915	See C<poll_cb> for an example.
546		916
547	=item IO::AIO::poll_cb	917	=item IO::AIO::poll_cb
548		918
549	Process all outstanding events on the result pipe. You have to call this	919	Process some outstanding events on the result pipe. You have to call this
550	regularly. Returns the number of events processed. Returns immediately	920	regularly. Returns the number of events processed. Returns immediately
551	when no events are outstanding.	921	when no events are outstanding. The amount of events processed depends on
		922	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		923
		924	If not all requests were processed for whatever reason, the filehandle
		925	will still be ready when C<poll_cb> returns.
552		926
553	Example: Install an Event watcher that automatically calls	927	Example: Install an Event watcher that automatically calls
554	IO::AIO::poll_cb with high priority:	928	IO::AIO::poll_cb with high priority:
555		929
556	Event->io (fd => IO::AIO::poll_fileno,	930	Event->io (fd => IO::AIO::poll_fileno,
557	poll => 'r', async => 1,	931	poll => 'r', async => 1,
558	cb => \&IO::AIO::poll_cb);	932	cb => \&IO::AIO::poll_cb);
559		933
		934	=item IO::AIO::max_poll_reqs $nreqs
		935
		936	=item IO::AIO::max_poll_time $seconds
		937
		938	These set the maximum number of requests (default C<0>, meaning infinity)
		939	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		940	the maximum amount of time (default C<0>, meaning infinity) spent in
		941	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		942	of time C<poll_cb> is allowed to use).
		943
		944	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		945	syscall per request processed, which is not normally a problem unless your
		946	callbacks are really really fast or your OS is really really slow (I am
		947	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		948
		949	Setting these is useful if you want to ensure some level of
		950	interactiveness when perl is not fast enough to process all requests in
		951	time.
		952
		953	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
		954
		955	Example: Install an Event watcher that automatically calls
		956	IO::AIO::poll_cb with low priority, to ensure that other parts of the
		957	program get the CPU sometimes even under high AIO load.
		958
		959	# try not to spend much more than 0.1s in poll_cb
		960	IO::AIO::max_poll_time 0.1;
		961
		962	# use a low priority so other tasks have priority
		963	Event->io (fd => IO::AIO::poll_fileno,
		964	poll => 'r', nice => 1,
		965	cb => &IO::AIO::poll_cb);
		966
560	=item IO::AIO::poll_wait	967	=item IO::AIO::poll_wait
561		968
562	Wait till the result filehandle becomes ready for reading (simply does a	969	Wait till the result filehandle becomes ready for reading (simply does a
563	C<select> on the filehandle. This is useful if you want to synchronously wait	970	C<select> on the filehandle. This is useful if you want to synchronously
564	for some requests to finish).	971	wait for some requests to finish).
565		972
566	See C<nreqs> for an example.	973	See C<nreqs> for an example.
567		974
		975	=item IO::AIO::poll
		976
		977	Waits until some requests have been handled.
		978
		979	Strictly equivalent to:
		980
		981	IO::AIO::poll_wait, IO::AIO::poll_cb
		982	if IO::AIO::nreqs;
		983
568	=item IO::AIO::nreqs	984	=item IO::AIO::flush
569		985
570	Returns the number of requests currently outstanding (i.e. for which their	986	Wait till all outstanding AIO requests have been handled.
571	callback has not been invoked yet).
572		987
573	Example: wait till there are no outstanding requests anymore:	988	Strictly equivalent to:
574		989
575	IO::AIO::poll_wait, IO::AIO::poll_cb	990	IO::AIO::poll_wait, IO::AIO::poll_cb
576	while IO::AIO::nreqs;	991	while IO::AIO::nreqs;
577		992
578	=item IO::AIO::flush	993	=head3 CONTROLLING THE NUMBER OF THREADS
579
580	Wait till all outstanding AIO requests have been handled.
581
582	Strictly equivalent to:
583
584	IO::AIO::poll_wait, IO::AIO::poll_cb
585	while IO::AIO::nreqs;
586
587	=item IO::AIO::poll
588
589	Waits until some requests have been handled.
590
591	Strictly equivalent to:
592
593	IO::AIO::poll_wait, IO::AIO::poll_cb
594	if IO::AIO::nreqs;
595		994
596	=item IO::AIO::min_parallel $nthreads	995	=item IO::AIO::min_parallel $nthreads
597		996
598	Set the minimum number of AIO threads to C<$nthreads>. The current default	997	Set the minimum number of AIO threads to C<$nthreads>. The current
599	is C<4>, which means four asynchronous operations can be done at one time	998	default is C<8>, which means eight asynchronous operations can execute
600	(the number of outstanding operations, however, is unlimited).	999	concurrently at any one time (the number of outstanding requests,
		1000	however, is unlimited).
601		1001
602	IO::AIO starts threads only on demand, when an AIO request is queued and	1002	IO::AIO starts threads only on demand, when an AIO request is queued and
603	no free thread exists.	1003	no free thread exists. Please note that queueing up a hundred requests can
		1004	create demand for a hundred threads, even if it turns out that everything
		1005	is in the cache and could have been processed faster by a single thread.
604		1006
605	It is recommended to keep the number of threads low, as some Linux	1007	It is recommended to keep the number of threads relatively low, as some
606	kernel versions will scale negatively with the number of threads (higher	1008	Linux kernel versions will scale negatively with the number of threads
607	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	1009	(higher parallelity => MUCH higher latency). With current Linux 2.6
608	threads should be fine.	1010	versions, 4-32 threads should be fine.
609		1011
610	Under most circumstances you don't need to call this function, as the	1012	Under most circumstances you don't need to call this function, as the
611	module selects a default that is suitable for low to moderate load.	1013	module selects a default that is suitable for low to moderate load.
612		1014
613	=item IO::AIO::max_parallel $nthreads	1015	=item IO::AIO::max_parallel $nthreads
…		…
622	This module automatically runs C<max_parallel 0> at program end, to ensure	1024	This module automatically runs C<max_parallel 0> at program end, to ensure
623	that all threads are killed and that there are no outstanding requests.	1025	that all threads are killed and that there are no outstanding requests.
624		1026
625	Under normal circumstances you don't need to call this function.	1027	Under normal circumstances you don't need to call this function.
626		1028
		1029	=item IO::AIO::max_idle $nthreads
		1030
		1031	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1032	threads that did not get a request to process within 10 seconds). That
		1033	means if a thread becomes idle while C<$nthreads> other threads are also
		1034	idle, it will free its resources and exit.
		1035
		1036	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1037	to allow for extremely high load situations, but want to free resources
		1038	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1039
		1040	The default is probably ok in most situations, especially if thread
		1041	creation is fast. If thread creation is very slow on your system you might
		1042	want to use larger values.
		1043
627	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1044	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
		1045
		1046	This is a very bad function to use in interactive programs because it
		1047	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1048	use an C<aio_group> together with a feed callback.
628		1049
629	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1050	Sets the maximum number of outstanding requests to C<$nreqs>. If you
630	try to queue up more than this number of requests, the caller will block until	1051	to queue up more than this number of requests, the next call to the
631	some requests have been handled.	1052	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1053	function will block until the limit is no longer exceeded.
632		1054
633	The default is very large, so normally there is no practical limit. If you	1055	The default value is very large, so there is no practical limit on the
634	queue up many requests in a loop it often improves speed if you set	1056	number of outstanding requests.
635	this to a relatively low number, such as C<100>.
636		1057
637	Under normal circumstances you don't need to call this function.	1058	You can still queue as many requests as you want. Therefore,
		1059	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
		1060	as a stop gap to shield against fatal memory overflow (with large values).
		1061
		1062	=head3 STATISTICAL INFORMATION
		1063
		1064	=item IO::AIO::nreqs
		1065
		1066	Returns the number of requests currently in the ready, execute or pending
		1067	states (i.e. for which their callback has not been invoked yet).
		1068
		1069	Example: wait till there are no outstanding requests anymore:
		1070
		1071	IO::AIO::poll_wait, IO::AIO::poll_cb
		1072	while IO::AIO::nreqs;
		1073
		1074	=item IO::AIO::nready
		1075
		1076	Returns the number of requests currently in the ready state (not yet
		1077	executed).
		1078
		1079	=item IO::AIO::npending
		1080
		1081	Returns the number of requests currently in the pending state (executed,
		1082	but not yet processed by poll_cb).
638		1083
639	=back	1084	=back
640		1085
641	=cut	1086	=cut
642		1087
…		…
654	or return undef;	1099	or return undef;
655		1100
656	*$sym	1101	*$sym
657	}	1102	}
658		1103
659	min_parallel 4;	1104	min_parallel 8;
660		1105
661	END {	1106	END {
662	max_parallel 0;	1107	min_parallel 1;
663	}	1108	flush;
		1109	};
664		1110
665	1;	1111	1;
666		1112
667	=head2 FORK BEHAVIOUR	1113	=head2 FORK BEHAVIOUR
668		1114
669	This module should do "the right thing" when the process using it forks:	1115	This module should do "the right thing" when the process using it forks:
670		1116
671	Before the fork, IO::AIO enters a quiescent state where no requests	1117	Before the fork, IO::AIO enters a quiescent state where no requests
672	can be added in other threads and no results will be processed. After	1118	can be added in other threads and no results will be processed. After
673	the fork the parent simply leaves the quiescent state and continues	1119	the fork the parent simply leaves the quiescent state and continues
674	request/result processing, while the child clears the request/result	1120	request/result processing, while the child frees the request/result queue
675	queue (so the requests started before the fork will only be handled in	1121	(so that the requests started before the fork will only be handled in the
676	the parent). Threads will be started on demand until the limit ste in the	1122	parent). Threads will be started on demand until the limit set in the
677	parent process has been reached again.	1123	parent process has been reached again.
678		1124
679	In short: the parent will, after a short pause, continue as if fork had	1125	In short: the parent will, after a short pause, continue as if fork had
680	not been called, while the child will act as if IO::AIO has not been used	1126	not been called, while the child will act as if IO::AIO has not been used
681	yet.	1127	yet.
682		1128
		1129	=head2 MEMORY USAGE
		1130
		1131	Per-request usage:
		1132
		1133	Each aio request uses - depending on your architecture - around 100-200
		1134	bytes of memory. In addition, stat requests need a stat buffer (possibly
		1135	a few hundred bytes), readdir requires a result buffer and so on. Perl
		1136	scalars and other data passed into aio requests will also be locked and
		1137	will consume memory till the request has entered the done state.
		1138
		1139	This is now awfully much, so queuing lots of requests is not usually a
		1140	problem.
		1141
		1142	Per-thread usage:
		1143
		1144	In the execution phase, some aio requests require more memory for
		1145	temporary buffers, and each thread requires a stack and other data
		1146	structures (usually around 16k-128k, depending on the OS).
		1147
		1148	=head1 KNOWN BUGS
		1149
		1150	Known bugs will be fixed in the next release.
		1151
683	=head1 SEE ALSO	1152	=head1 SEE ALSO
684		1153
685	L<Coro>, L<Linux::AIO> (obsolete).	1154	L<Coro::AIO>.
686		1155
687	=head1 AUTHOR	1156	=head1 AUTHOR
688		1157
689	Marc Lehmann <schmorp@schmorp.de>	1158	Marc Lehmann <schmorp@schmorp.de>
690	http://home.schmorp.de/	1159	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.54 by root, Sun Oct 22 00:19:05 2006 UTC vs. Revision 1.89 by root, Sun Oct 29 11:03:18 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.54 by root, Sun Oct 22 00:19:05 2006 UTC vs.
Revision 1.89 by root, Sun Oct 29 11:03:18 2006 UTC