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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC vs.
Revision 1.97 by root, Sat Dec 23 04:49:37 2006 UTC

…		…
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
51	=head1 DESCRIPTION	52	=head1 DESCRIPTION
52		53
53	This module implements asynchronous I/O using whatever means your	54	This module implements asynchronous I/O using whatever means your
54	operating system supports.	55	operating system supports.
55		56
		57	Asynchronous means that operations that can normally block your program
		58	(e.g. reading from disk) will be done asynchronously: the operation
		59	will still block, but you can do something else in the meantime. This
		60	is extremely useful for programs that need to stay interactive even
		61	when doing heavy I/O (GUI programs, high performance network servers
		62	etc.), but can also be used to easily do operations in parallel that are
		63	normally done sequentially, e.g. stat'ing many files, which is much faster
		64	on a RAID volume or over NFS when you do a number of stat operations
		65	concurrently.
		66
		67	While most of this works on all types of file descriptors (for example
		68	sockets), using these functions on file descriptors that support
		69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or
		70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop
		71	for that (such as the L<Event\|Event> module): IO::AIO will naturally fit
		72	into such an event loop itself.
		73
56	Currently, a number of threads are started that execute your read/writes	74	In this version, a number of threads are started that execute your
57	and signal their completion. You don't need thread support in perl, and	75	requests and signal their completion. You don't need thread support
58	the threads created by this module will not be visible to perl. In the	76	in perl, and the threads created by this module will not be visible
59	future, this module might make use of the native aio functions available	77	to perl. In the future, this module might make use of the native aio
60	on many operating systems. However, they are often not well-supported	78	functions available on many operating systems. However, they are often
61	(Linux doesn't allow them on normal files currently, for example),	79	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	and they would only support aio_read and aio_write, so the remaining	80	files currently, for example), and they would only support aio_read and
63	functionality would have to be implemented using threads anyway.	81	aio_write, so the remaining functionality would have to be implemented
		82	using threads anyway.
64		83
65	Although the module will work with in the presence of other threads,	84	Although the module will work with in the presence of other (Perl-)
66	it is currently not reentrant in any way, so use appropriate locking	85	threads, it is currently not reentrant in any way, so use appropriate
67	yourself, always call C<poll_cb> from within the same thread, or never	86	locking yourself, always call C<poll_cb> from within the same thread, or
68	call C<poll_cb> (or other C<aio_> functions) recursively.	87	never call C<poll_cb> (or other C<aio_> functions) recursively.
		88
		89	=head2 EXAMPLE
		90
		91	This is a simple example that uses the Event module and loads
		92	F</etc/passwd> asynchronously:
		93
		94	use Fcntl;
		95	use Event;
		96	use IO::AIO;
		97
		98	# register the IO::AIO callback with Event
		99	Event->io (fd => IO::AIO::poll_fileno,
		100	poll => 'r',
		101	cb => \&IO::AIO::poll_cb);
		102
		103	# queue the request to open /etc/passwd
		104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		105	my $fh = shift
		106	or die "error while opening: $!";
		107
		108	# stat'ing filehandles is generally non-blocking
		109	my $size = -s $fh;
		110
		111	# queue a request to read the file
		112	my $contents;
		113	aio_read $fh, 0, $size, $contents, 0, sub {
		114	$_[0] == $size
		115	or die "short read: $!";
		116
		117	close $fh;
		118
		119	# file contents now in $contents
		120	print $contents;
		121
		122	# exit event loop and program
		123	Event::unloop;
		124	};
		125	};
		126
		127	# possibly queue up other requests, or open GUI windows,
		128	# check for sockets etc. etc.
		129
		130	# process events as long as there are some:
		131	Event::loop;
		132
		133	=head1 REQUEST ANATOMY AND LIFETIME
		134
		135	Every C<aio_*> function creates a request. which is a C data structure not
		136	directly visible to Perl.
		137
		138	If called in non-void context, every request function returns a Perl
		139	object representing the request. In void context, nothing is returned,
		140	which saves a bit of memory.
		141
		142	The perl object is a fairly standard ref-to-hash object. The hash contents
		143	are not used by IO::AIO so you are free to store anything you like in it.
		144
		145	During their existance, aio requests travel through the following states,
		146	in order:
		147
		148	=over 4
		149
		150	=item ready
		151
		152	Immediately after a request is created it is put into the ready state,
		153	waiting for a thread to execute it.
		154
		155	=item execute
		156
		157	A thread has accepted the request for processing and is currently
		158	executing it (e.g. blocking in read).
		159
		160	=item pending
		161
		162	The request has been executed and is waiting for result processing.
		163
		164	While request submission and execution is fully asynchronous, result
		165	processing is not and relies on the perl interpreter calling C<poll_cb>
		166	(or another function with the same effect).
		167
		168	=item result
		169
		170	The request results are processed synchronously by C<poll_cb>.
		171
		172	The C<poll_cb> function will process all outstanding aio requests by
		173	calling their callbacks, freeing memory associated with them and managing
		174	any groups they are contained in.
		175
		176	=item done
		177
		178	Request has reached the end of its lifetime and holds no resources anymore
		179	(except possibly for the Perl object, but its connection to the actual
		180	aio request is severed and calling its methods will either do nothing or
		181	result in a runtime error).
		182
		183	=back
69		184
70	=cut	185	=cut
71		186
72	package IO::AIO;	187	package IO::AIO;
73		188
…		…
75	use strict 'vars';	190	use strict 'vars';
76		191
77	use base 'Exporter';	192	use base 'Exporter';
78		193
79	BEGIN {	194	BEGIN {
80	our $VERSION = '2.0';	195	our $VERSION = '2.3';
81		196
82	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	197	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
83	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	198	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
84	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	199	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
85	aio_group aio_nop);	200	aio_move aio_copy aio_group aio_nop aio_mknod);
86	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
87	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
88	min_parallel max_parallel max_outstanding nreqs);	203	min_parallel max_parallel max_idle
		204	nreqs nready npending nthreads
		205	max_poll_time max_poll_reqs);
89		206
90	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
91		208
92	require XSLoader;	209	require XSLoader;
93	XSLoader::load ("IO::AIO", $VERSION);	210	XSLoader::load ("IO::AIO", $VERSION);
94	}	211	}
95		212
96	=head1 FUNCTIONS	213	=head1 FUNCTIONS
97		214
98	=head2 AIO FUNCTIONS	215	=head2 AIO REQUEST FUNCTIONS
99		216
100	All the C<aio_*> calls are more or less thin wrappers around the syscall	217	All the C<aio_*> calls are more or less thin wrappers around the syscall
101	with the same name (sans C<aio_>). The arguments are similar or identical,	218	with the same name (sans C<aio_>). The arguments are similar or identical,
102	and they all accept an additional (and optional) C<$callback> argument	219	and they all accept an additional (and optional) C<$callback> argument
103	which must be a code reference. This code reference will get called with	220	which must be a code reference. This code reference will get called with
…		…
106	syscall has been executed asynchronously.	223	syscall has been executed asynchronously.
107		224
108	All functions expecting a filehandle keep a copy of the filehandle	225	All functions expecting a filehandle keep a copy of the filehandle
109	internally until the request has finished.	226	internally until the request has finished.
110		227
111	All requests return objects of type L<IO::AIO::REQ> that allow further	228	All functions return request objects of type L<IO::AIO::REQ> that allow
112	manipulation of those requests while they are in-flight.	229	further manipulation of those requests while they are in-flight.
113		230
114	The pathnames you pass to these routines I<must> be absolute and	231	The pathnames you pass to these routines I<must> be absolute and
115	encoded in byte form. The reason for the former is that at the time the	232	encoded as octets. The reason for the former is that at the time the
116	request is being executed, the current working directory could have	233	request is being executed, the current working directory could have
117	changed. Alternatively, you can make sure that you never change the	234	changed. Alternatively, you can make sure that you never change the
118	current working directory.	235	current working directory anywhere in the program and then use relative
		236	paths.
119		237
120	To encode pathnames to byte form, either make sure you either: a)	238	To encode pathnames as octets, either make sure you either: a) always pass
121	always pass in filenames you got from outside (command line, readdir	239	in filenames you got from outside (command line, readdir etc.) without
122	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	240	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
123	your pathnames to the locale (or other) encoding in effect in the user	241	your pathnames to the locale (or other) encoding in effect in the user
124	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	242	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
125	use something else.	243	use something else to ensure your scalar has the correct contents.
		244
		245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		246	handles correctly wether it is set or not.
126		247
127	=over 4	248	=over 4
128		249
129	=item aioreq_pri $pri	250	=item $prev_pri = aioreq_pri [$pri]
130		251
131	Sets the priority for the next aio request. The default priority	252	Returns the priority value that would be used for the next request and, if
		253	C<$pri> is given, sets the priority for the next aio request.
		254
132	is C<0>, the minimum and maximum priorities are C<-4> and C<4>,	255	The default priority is C<0>, the minimum and maximum priorities are C<-4>
133	respectively. Requests with higher priority will be serviced first.	256	and C<4>, respectively. Requests with higher priority will be serviced
		257	first.
134		258
135	The priority will be reset to C<0> after each call to one of the C<aio_>	259	The priority will be reset to C<0> after each call to one of the C<aio_*>
136	functions.	260	functions.
137		261
138	Example: open a file with low priority, then read something from it with	262	Example: open a file with low priority, then read something from it with
139	higher priority so the read request is serviced before other low priority	263	higher priority so the read request is serviced before other low priority
140	open requests (potentially spamming the cache):	264	open requests (potentially spamming the cache):
…		…
150	};	274	};
151		275
152	=item aioreq_nice $pri_adjust	276	=item aioreq_nice $pri_adjust
153		277
154	Similar to C<aioreq_pri>, but subtracts the given value from the current	278	Similar to C<aioreq_pri>, but subtracts the given value from the current
155	priority, so effects are cumulative.	279	priority, so the effect is cumulative.
156		280
157	=item aio_open $pathname, $flags, $mode, $callback->($fh)	281	=item aio_open $pathname, $flags, $mode, $callback->($fh)
158		282
159	Asynchronously open or create a file and call the callback with a newly	283	Asynchronously open or create a file and call the callback with a newly
160	created filehandle for the file.	284	created filehandle for the file.
…		…
211	aio_read $fh, 7, 15, $buffer, 0, sub {	335	aio_read $fh, 7, 15, $buffer, 0, sub {
212	$_[0] > 0 or die "read error: $!";	336	$_[0] > 0 or die "read error: $!";
213	print "read $_[0] bytes: <$buffer>\n";	337	print "read $_[0] bytes: <$buffer>\n";
214	};	338	};
215		339
216	=item aio_move $srcpath, $dstpath, $callback->($status)
217
218	[EXPERIMENTAL due to internal aio_group use]
219
220	Try to move the I<file> (directories not supported as either source or
221	destination) from C<$srcpath> to C<$dstpath> and call the callback with
222	the C<0> (error) or C<-1> ok.
223
224	This is a composite request that tries to rename(2) the file first. If
225	rename files with C<EXDEV>, it creates the destination file with mode 0200
226	and copies the contents of the source file into it using C<aio_sendfile>,
227	followed by restoring atime, mtime, access mode and uid/gid, in that
228	order, and unlinking the C<$srcpath>.
229
230	If an error occurs, the partial destination file will be unlinked, if
231	possible, except when setting atime, mtime, access mode and uid/gid, where
232	errors are being ignored.
233
234	=cut
235
236	sub aio_move($$$) {
237	my ($src, $dst, $cb) = @_;
238
239	my $grp = aio_group $cb;
240
241	add $grp aio_rename $src, $dst, sub {
242	if ($_[0] && $! == EXDEV) {
243	add $grp aio_open $src, O_RDONLY, 0, sub {
244	if (my $src_fh = $_[0]) {
245	my @stat = stat $src_fh;
246
247	add $grp aio_open $dst, O_WRONLY, 0200, sub {
248	if (my $dst_fh = $_[0]) {
249	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
250	close $src_fh;
251
252	if ($_[0] == $stat[7]) {
253	utime $stat[8], $stat[9], $dst;
254	chmod $stat[2] & 07777, $dst_fh;
255	chown $stat[4], $stat[5], $dst_fh;
256	close $dst_fh;
257
258	add $grp aio_unlink $src, sub {
259	$grp->result ($_[0]);
260	};
261	} else {
262	my $errno = $!;
263	add $grp aio_unlink $dst, sub {
264	$! = $errno;
265	$grp->result (-1);
266	};
267	}
268	};
269	} else {
270	$grp->result (-1);
271	}
272	},
273
274	} else {
275	$grp->result (-1);
276	}
277	};
278	} else {
279	$grp->result ($_[0]);
280	}
281	};
282
283	$grp
284	}
285
286	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	340	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
287		341
288	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	342	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
289	reading at byte offset C<$in_offset>, and starts writing at the current	343	reading at byte offset C<$in_offset>, and starts writing at the current
290	file offset of C<$out_fh>. Because of that, it is not safe to issue more	344	file offset of C<$out_fh>. Because of that, it is not safe to issue more
…		…
345	=item aio_unlink $pathname, $callback->($status)	399	=item aio_unlink $pathname, $callback->($status)
346		400
347	Asynchronously unlink (delete) a file and call the callback with the	401	Asynchronously unlink (delete) a file and call the callback with the
348	result code.	402	result code.
349		403
		404	=item aio_mknod $path, $mode, $dev, $callback->($status)
		405
		406	[EXPERIMENTAL]
		407
		408	Asynchronously create a device node (or fifo). See mknod(2).
		409
		410	The only (POSIX-) portable way of calling this function is:
		411
		412	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		413
350	=item aio_link $srcpath, $dstpath, $callback->($status)	414	=item aio_link $srcpath, $dstpath, $callback->($status)
351		415
352	Asynchronously create a new link to the existing object at C<$srcpath> at	416	Asynchronously create a new link to the existing object at C<$srcpath> at
353	the path C<$dstpath> and call the callback with the result code.	417	the path C<$dstpath> and call the callback with the result code.
354		418
355	=item aio_symlink $srcpath, $dstpath, $callback->($status)	419	=item aio_symlink $srcpath, $dstpath, $callback->($status)
356		420
357	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	421	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
358	the path C<$dstpath> and call the callback with the result code.	422	the path C<$dstpath> and call the callback with the result code.
		423
		424	=item aio_readlink $path, $callback->($link)
		425
		426	Asynchronously read the symlink specified by C<$path> and pass it to
		427	the callback. If an error occurs, nothing or undef gets passed to the
		428	callback.
359		429
360	=item aio_rename $srcpath, $dstpath, $callback->($status)	430	=item aio_rename $srcpath, $dstpath, $callback->($status)
361		431
362	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	432	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
363	rename(2) and call the callback with the result code.	433	rename(2) and call the callback with the result code.
…		…
374	sorted, and will B<NOT> include the C<.> and C<..> entries.	444	sorted, and will B<NOT> include the C<.> and C<..> entries.
375		445
376	The callback a single argument which is either C<undef> or an array-ref	446	The callback a single argument which is either C<undef> or an array-ref
377	with the filenames.	447	with the filenames.
378		448
		449	=item aio_copy $srcpath, $dstpath, $callback->($status)
		450
		451	Try to copy the I<file> (directories not supported as either source or
		452	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		453	the C<0> (error) or C<-1> ok.
		454
		455	This is a composite request that it creates the destination file with
		456	mode 0200 and copies the contents of the source file into it using
		457	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		458	uid/gid, in that order.
		459
		460	If an error occurs, the partial destination file will be unlinked, if
		461	possible, except when setting atime, mtime, access mode and uid/gid, where
		462	errors are being ignored.
		463
		464	=cut
		465
		466	sub aio_copy($$;$) {
		467	aio_block {
		468	my ($src, $dst, $cb) = @_;
		469
		470	my $pri = aioreq_pri;
		471	my $grp = aio_group $cb;
		472
		473	aioreq_pri $pri;
		474	add $grp aio_open $src, O_RDONLY, 0, sub {
		475	if (my $src_fh = $_[0]) {
		476	my @stat = stat $src_fh;
		477
		478	aioreq_pri $pri;
		479	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		480	if (my $dst_fh = $_[0]) {
		481	aioreq_pri $pri;
		482	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		483	if ($_[0] == $stat[7]) {
		484	$grp->result (0);
		485	close $src_fh;
		486
		487	# those should not normally block. should. should.
		488	utime $stat[8], $stat[9], $dst;
		489	chmod $stat[2] & 07777, $dst_fh;
		490	chown $stat[4], $stat[5], $dst_fh;
		491	close $dst_fh;
		492	} else {
		493	$grp->result (-1);
		494	close $src_fh;
		495	close $dst_fh;
		496
		497	aioreq $pri;
		498	add $grp aio_unlink $dst;
		499	}
		500	};
		501	} else {
		502	$grp->result (-1);
		503	}
		504	},
		505
		506	} else {
		507	$grp->result (-1);
		508	}
		509	};
		510
		511	$grp
		512	}
		513	}
		514
		515	=item aio_move $srcpath, $dstpath, $callback->($status)
		516
		517	Try to move the I<file> (directories not supported as either source or
		518	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		519	the C<0> (error) or C<-1> ok.
		520
		521	This is a composite request that tries to rename(2) the file first. If
		522	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		523	that is successful, unlinking the C<$srcpath>.
		524
		525	=cut
		526
		527	sub aio_move($$;$) {
		528	aio_block {
		529	my ($src, $dst, $cb) = @_;
		530
		531	my $pri = aioreq_pri;
		532	my $grp = aio_group $cb;
		533
		534	aioreq_pri $pri;
		535	add $grp aio_rename $src, $dst, sub {
		536	if ($_[0] && $! == EXDEV) {
		537	aioreq_pri $pri;
		538	add $grp aio_copy $src, $dst, sub {
		539	$grp->result ($_[0]);
		540
		541	if (!$_[0]) {
		542	aioreq_pri $pri;
		543	add $grp aio_unlink $src;
		544	}
		545	};
		546	} else {
		547	$grp->result ($_[0]);
		548	}
		549	};
		550
		551	$grp
		552	}
		553	}
		554
379	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	555	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
380		556
381	[EXPERIMENTAL due to internal aio_group use]
382
383	Scans a directory (similar to C<aio_readdir>) but additionally tries to	557	Scans a directory (similar to C<aio_readdir>) but additionally tries to
384	separate the entries of directory C<$path> into two sets of names, ones	558	efficiently separate the entries of directory C<$path> into two sets of
385	you can recurse into (directories or links to them), and ones you cannot	559	names, directories you can recurse into (directories), and ones you cannot
386	recurse into (everything else).	560	recurse into (everything else, including symlinks to directories).
387		561
388	C<aio_scandir> is a composite request that creates of many sub requests_	562	C<aio_scandir> is a composite request that creates of many sub requests_
389	C<$maxreq> specifies the maximum number of outstanding aio requests that	563	C<$maxreq> specifies the maximum number of outstanding aio requests that
390	this function generates. If it is C<< <= 0 >>, then a suitable default	564	this function generates. If it is C<< <= 0 >>, then a suitable default
391	will be chosen (currently 6).	565	will be chosen (currently 4).
392		566
393	On error, the callback is called without arguments, otherwise it receives	567	On error, the callback is called without arguments, otherwise it receives
394	two array-refs with path-relative entry names.	568	two array-refs with path-relative entry names.
395		569
396	Example:	570	Example:
…		…
431	directory counting heuristic.	605	directory counting heuristic.
432		606
433	=cut	607	=cut
434		608
435	sub aio_scandir($$$) {	609	sub aio_scandir($$$) {
		610	aio_block {
436	my ($path, $maxreq, $cb) = @_;	611	my ($path, $maxreq, $cb) = @_;
437		612
		613	my $pri = aioreq_pri;
		614
438	my $grp = aio_group $cb;	615	my $grp = aio_group $cb;
439		616
440	$maxreq = 6 if $maxreq <= 0;	617	$maxreq = 4 if $maxreq <= 0;
441		618
442	# stat once	619	# stat once
		620	aioreq_pri $pri;
443	add $grp aio_stat $path, sub {	621	add $grp aio_stat $path, sub {
444	return $grp->result () if $_[0];	622	return $grp->result () if $_[0];
445	my $now = time;	623	my $now = time;
446	my $hash1 = join ":", (stat _)[0,1,3,7,9];	624	my $hash1 = join ":", (stat _)[0,1,3,7,9];
447		625
448	# read the directory entries	626	# read the directory entries
		627	aioreq_pri $pri;
449	add $grp aio_readdir $path, sub {	628	add $grp aio_readdir $path, sub {
450	my $entries = shift	629	my $entries = shift
451	or return $grp->result ();	630	or return $grp->result ();
452		631
453	# stat the dir another time	632	# stat the dir another time
		633	aioreq_pri $pri;
454	add $grp aio_stat $path, sub {	634	add $grp aio_stat $path, sub {
455	my $hash2 = join ":", (stat _)[0,1,3,7,9];	635	my $hash2 = join ":", (stat _)[0,1,3,7,9];
456		636
457	my $ndirs;	637	my $ndirs;
458		638
459	# take the slow route if anything looks fishy	639	# take the slow route if anything looks fishy
460	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	640	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
461	$ndirs = -1;	641	$ndirs = -1;
462	} else {	642	} else {
463	# if nlink == 2, we are finished	643	# if nlink == 2, we are finished
464	# on non-posix-fs's, we rely on nlink < 2	644	# on non-posix-fs's, we rely on nlink < 2
465	$ndirs = (stat _)[3] - 2	645	$ndirs = (stat _)[3] - 2
466	or return $grp->result ([], $entries);	646	or return $grp->result ([], $entries);
467	}	647	}
468		648
469	# sort into likely dirs and likely nondirs	649	# sort into likely dirs and likely nondirs
470	# dirs == files without ".", short entries first	650	# dirs == files without ".", short entries first
471	$entries = [map $_->[0],	651	$entries = [map $_->[0],
472	sort { $b->[1] cmp $a->[1] }	652	sort { $b->[1] cmp $a->[1] }
473	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	653	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
474	@$entries];	654	@$entries];
475		655
476	my (@dirs, @nondirs);	656	my (@dirs, @nondirs);
477		657
478	my ($statcb, $schedcb);
479	my $nreq = 0;
480
481	my $statgrp = add $grp aio_group;	658	my $statgrp = add $grp aio_group sub {
482
483	$schedcb = sub {
484	if (@$entries) {
485	if ($nreq < $maxreq) {
486	my $ent = pop @$entries;
487	$nreq++;
488	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
489	}
490	} elsif (!$nreq) {
491	# finished
492	$statgrp->cancel;
493	undef $statcb;
494	undef $schedcb;
495	$grp->result (\@dirs, \@nondirs);	659	$grp->result (\@dirs, \@nondirs);
496	}	660	};
		661
		662	limit $statgrp $maxreq;
		663	feed $statgrp sub {
		664	return unless @$entries;
		665	my $entry = pop @$entries;
		666
		667	aioreq_pri $pri;
		668	add $statgrp aio_stat "$path/$entry/.", sub {
		669	if ($_[0] < 0) {
		670	push @nondirs, $entry;
		671	} else {
		672	# need to check for real directory
		673	aioreq_pri $pri;
		674	add $statgrp aio_lstat "$path/$entry", sub {
		675	if (-d _) {
		676	push @dirs, $entry;
		677
		678	unless (--$ndirs) {
		679	push @nondirs, @$entries;
		680	feed $statgrp;
		681	}
		682	} else {
		683	push @nondirs, $entry;
		684	}
		685	}
		686	}
		687	};
		688	};
497	};	689	};
498	$statcb = sub {
499	my ($status, $entry) = @_;
500
501	if ($status < 0) {
502	$nreq--;
503	push @nondirs, $entry;
504	&$schedcb;
505	} else {
506	# need to check for real directory
507	add $grp aio_lstat "$path/$entry", sub {
508	$nreq--;
509
510	if (-d _) {
511	push @dirs, $entry;
512
513	if (!--$ndirs) {
514	push @nondirs, @$entries;
515	$entries = [];
516	}
517	} else {
518	push @nondirs, $entry;
519	}
520
521	&$schedcb;
522	}
523	}
524	};
525
526	&$schedcb while @$entries && $nreq < $maxreq;
527	};	690	};
528	};	691	};
		692
		693	$grp
529	};	694	}
530
531	$grp
532	}	695	}
533		696
534	=item aio_fsync $fh, $callback->($status)	697	=item aio_fsync $fh, $callback->($status)
535		698
536	Asynchronously call fsync on the given filehandle and call the callback	699	Asynchronously call fsync on the given filehandle and call the callback
…		…
544	If this call isn't available because your OS lacks it or it couldn't be	707	If this call isn't available because your OS lacks it or it couldn't be
545	detected, it will be emulated by calling C<fsync> instead.	708	detected, it will be emulated by calling C<fsync> instead.
546		709
547	=item aio_group $callback->(...)	710	=item aio_group $callback->(...)
548		711
549	[EXPERIMENTAL]
550
551	This is a very special aio request: Instead of doing something, it is a	712	This is a very special aio request: Instead of doing something, it is a
552	container for other aio requests, which is useful if you want to bundle	713	container for other aio requests, which is useful if you want to bundle
553	many requests into a single, composite, request.	714	many requests into a single, composite, request with a definite callback
		715	and the ability to cancel the whole request with its subrequests.
554		716
555	Returns an object of class L<IO::AIO::GRP>. See its documentation below	717	Returns an object of class L<IO::AIO::GRP>. See its documentation below
556	for more info.	718	for more info.
557		719
558	Example:	720	Example:
…		…
577	phase and still requires a worker thread. Thus, the callback will not	739	phase and still requires a worker thread. Thus, the callback will not
578	be executed immediately but only after other requests in the queue have	740	be executed immediately but only after other requests in the queue have
579	entered their execution phase. This can be used to measure request	741	entered their execution phase. This can be used to measure request
580	latency.	742	latency.
581		743
582	=item IO::AIO::aio_sleep $fractional_seconds, $callback->() NOT EXPORTED	744	=item IO::AIO::aio_busy $fractional_seconds, $callback->() NOT EXPORTED
583		745
584	Mainly used for debugging and benchmarking, this aio request puts one of	746	Mainly used for debugging and benchmarking, this aio request puts one of
585	the request workers to sleep for the given time.	747	the request workers to sleep for the given time.
586		748
587	While it is theoretically handy to have simple I/O scheduling requests	749	While it is theoretically handy to have simple I/O scheduling requests
588	like sleep and file handle readable/writable, the overhead this creates	750	like sleep and file handle readable/writable, the overhead this creates is
589	is immense, so do not use this function except to put your application	751	immense (it blocks a thread for a long time) so do not use this function
590	under artificial I/O pressure.	752	except to put your application under artificial I/O pressure.
591		753
592	=back	754	=back
593		755
594	=head2 IO::AIO::REQ CLASS	756	=head2 IO::AIO::REQ CLASS
595		757
596	All non-aggregate C<aio_*> functions return an object of this class when	758	All non-aggregate C<aio_*> functions return an object of this class when
597	called in non-void context.	759	called in non-void context.
598
599	A request always moves through the following five states in its lifetime,
600	in order: B<ready> (request has been created, but has not been executed
601	yet), B<execute> (request is currently being executed), B<pending>
602	(request has been executed but callback has not been called yet),
603	B<result> (results are being processed synchronously, includes calling the
604	callback) and B<done> (request has reached the end of its lifetime and
605	holds no resources anymore).
606		760
607	=over 4	761	=over 4
608		762
609	=item cancel $req	763	=item cancel $req
610		764
…		…
664	=item * They can also can also be added to other IO::AIO::GRP objects.	818	=item * They can also can also be added to other IO::AIO::GRP objects.
665		819
666	=item * You must not add requests to a group from within the group callback (or	820	=item * You must not add requests to a group from within the group callback (or
667	any later time).	821	any later time).
668		822
669	=item * This does not harmonise well with C<max_outstanding>, so best do
670	not combine C<aio_group> with it. Groups and feeders are recommended for
671	this kind of concurrency-limiting.
672
673	=back	823	=back
674		824
675	Their lifetime, simplified, looks like this: when they are empty, they	825	Their lifetime, simplified, looks like this: when they are empty, they
676	will finish very quickly. If they contain only requests that are in the	826	will finish very quickly. If they contain only requests that are in the
677	C<done> state, they will also finish. Otherwise they will continue to	827	C<done> state, they will also finish. Otherwise they will continue to
…		…
692	be added, including other groups, as long as you do not create circular	842	be added, including other groups, as long as you do not create circular
693	dependencies.	843	dependencies.
694		844
695	Returns all its arguments.	845	Returns all its arguments.
696		846
		847	=item $grp->cancel_subs
		848
		849	Cancel all subrequests and clears any feeder, but not the group request
		850	itself. Useful when you queued a lot of events but got a result early.
		851
697	=item $grp->result (...)	852	=item $grp->result (...)
698		853
699	Set the result value(s) that will be passed to the group callback when all	854	Set the result value(s) that will be passed to the group callback when all
700	subrequests have finished. By default, no argument will be passed.	855	subrequests have finished and set thre groups errno to the current value
		856	of errno (just like calling C<errno> without an error number). By default,
		857	no argument will be passed and errno is zero.
		858
		859	=item $grp->errno ([$errno])
		860
		861	Sets the group errno value to C<$errno>, or the current value of errno
		862	when the argument is missing.
		863
		864	Every aio request has an associated errno value that is restored when
		865	the callback is invoked. This method lets you change this value from its
		866	default (0).
		867
		868	Calling C<result> will also set errno, so make sure you either set C<$!>
		869	before the call to C<result>, or call c<errno> after it.
701		870
702	=item feed $grp $callback->($grp)	871	=item feed $grp $callback->($grp)
703
704	[VERY EXPERIMENTAL]
705		872
706	Sets a feeder/generator on this group: every group can have an attached	873	Sets a feeder/generator on this group: every group can have an attached
707	generator that generates requests if idle. The idea behind this is that,	874	generator that generates requests if idle. The idea behind this is that,
708	although you could just queue as many requests as you want in a group,	875	although you could just queue as many requests as you want in a group,
709	this might starve other requests for a potentially long time. For	876	this might starve other requests for a potentially long time. For
…		…
746		913
747	=back	914	=back
748		915
749	=head2 SUPPORT FUNCTIONS	916	=head2 SUPPORT FUNCTIONS
750		917
		918	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		919
751	=over 4	920	=over 4
752		921
753	=item $fileno = IO::AIO::poll_fileno	922	=item $fileno = IO::AIO::poll_fileno
754		923
755	Return the I<request result pipe file descriptor>. This filehandle must be	924	Return the I<request result pipe file descriptor>. This filehandle must be
…		…
759		928
760	See C<poll_cb> for an example.	929	See C<poll_cb> for an example.
761		930
762	=item IO::AIO::poll_cb	931	=item IO::AIO::poll_cb
763		932
764	Process all outstanding events on the result pipe. You have to call this	933	Process some outstanding events on the result pipe. You have to call this
765	regularly. Returns the number of events processed. Returns immediately	934	regularly. Returns the number of events processed. Returns immediately
766	when no events are outstanding.	935	when no events are outstanding. The amount of events processed depends on
		936	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		937
		938	If not all requests were processed for whatever reason, the filehandle
		939	will still be ready when C<poll_cb> returns.
767		940
768	Example: Install an Event watcher that automatically calls	941	Example: Install an Event watcher that automatically calls
769	IO::AIO::poll_cb with high priority:	942	IO::AIO::poll_cb with high priority:
770		943
771	Event->io (fd => IO::AIO::poll_fileno,	944	Event->io (fd => IO::AIO::poll_fileno,
772	poll => 'r', async => 1,	945	poll => 'r', async => 1,
773	cb => \&IO::AIO::poll_cb);	946	cb => \&IO::AIO::poll_cb);
774		947
		948	=item IO::AIO::max_poll_reqs $nreqs
		949
		950	=item IO::AIO::max_poll_time $seconds
		951
		952	These set the maximum number of requests (default C<0>, meaning infinity)
		953	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		954	the maximum amount of time (default C<0>, meaning infinity) spent in
		955	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		956	of time C<poll_cb> is allowed to use).
		957
		958	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		959	syscall per request processed, which is not normally a problem unless your
		960	callbacks are really really fast or your OS is really really slow (I am
		961	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		962
		963	Setting these is useful if you want to ensure some level of
		964	interactiveness when perl is not fast enough to process all requests in
		965	time.
		966
		967	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
		968
		969	Example: Install an Event watcher that automatically calls
		970	IO::AIO::poll_cb with low priority, to ensure that other parts of the
		971	program get the CPU sometimes even under high AIO load.
		972
		973	# try not to spend much more than 0.1s in poll_cb
		974	IO::AIO::max_poll_time 0.1;
		975
		976	# use a low priority so other tasks have priority
		977	Event->io (fd => IO::AIO::poll_fileno,
		978	poll => 'r', nice => 1,
		979	cb => &IO::AIO::poll_cb);
		980
775	=item IO::AIO::poll_wait	981	=item IO::AIO::poll_wait
776		982
		983	If there are any outstanding requests and none of them in the result
777	Wait till the result filehandle becomes ready for reading (simply does a	984	phase, wait till the result filehandle becomes ready for reading (simply
778	C<select> on the filehandle. This is useful if you want to synchronously wait	985	does a C<select> on the filehandle. This is useful if you want to
779	for some requests to finish).	986	synchronously wait for some requests to finish).
780		987
781	See C<nreqs> for an example.	988	See C<nreqs> for an example.
782		989
		990	=item IO::AIO::poll
		991
		992	Waits until some requests have been handled.
		993
		994	Returns the number of requests processed, but is otherwise strictly
		995	equivalent to:
		996
		997	IO::AIO::poll_wait, IO::AIO::poll_cb
		998
783	=item IO::AIO::nreqs	999	=item IO::AIO::flush
784		1000
785	Returns the number of requests currently outstanding (i.e. for which their	1001	Wait till all outstanding AIO requests have been handled.
786	callback has not been invoked yet).
787		1002
788	Example: wait till there are no outstanding requests anymore:	1003	Strictly equivalent to:
789		1004
790	IO::AIO::poll_wait, IO::AIO::poll_cb	1005	IO::AIO::poll_wait, IO::AIO::poll_cb
791	while IO::AIO::nreqs;	1006	while IO::AIO::nreqs;
792		1007
793	=item IO::AIO::flush	1008	=head3 CONTROLLING THE NUMBER OF THREADS
794
795	Wait till all outstanding AIO requests have been handled.
796
797	Strictly equivalent to:
798
799	IO::AIO::poll_wait, IO::AIO::poll_cb
800	while IO::AIO::nreqs;
801
802	=item IO::AIO::poll
803
804	Waits until some requests have been handled.
805
806	Strictly equivalent to:
807
808	IO::AIO::poll_wait, IO::AIO::poll_cb
809	if IO::AIO::nreqs;
810		1009
811	=item IO::AIO::min_parallel $nthreads	1010	=item IO::AIO::min_parallel $nthreads
812		1011
813	Set the minimum number of AIO threads to C<$nthreads>. The current	1012	Set the minimum number of AIO threads to C<$nthreads>. The current
814	default is C<8>, which means eight asynchronous operations can execute	1013	default is C<8>, which means eight asynchronous operations can execute
815	concurrently at any one time (the number of outstanding requests,	1014	concurrently at any one time (the number of outstanding requests,
816	however, is unlimited).	1015	however, is unlimited).
817		1016
818	IO::AIO starts threads only on demand, when an AIO request is queued and	1017	IO::AIO starts threads only on demand, when an AIO request is queued and
819	no free thread exists.	1018	no free thread exists. Please note that queueing up a hundred requests can
		1019	create demand for a hundred threads, even if it turns out that everything
		1020	is in the cache and could have been processed faster by a single thread.
820		1021
821	It is recommended to keep the number of threads relatively low, as some	1022	It is recommended to keep the number of threads relatively low, as some
822	Linux kernel versions will scale negatively with the number of threads	1023	Linux kernel versions will scale negatively with the number of threads
823	(higher parallelity => MUCH higher latency). With current Linux 2.6	1024	(higher parallelity => MUCH higher latency). With current Linux 2.6
824	versions, 4-32 threads should be fine.	1025	versions, 4-32 threads should be fine.
…		…
838	This module automatically runs C<max_parallel 0> at program end, to ensure	1039	This module automatically runs C<max_parallel 0> at program end, to ensure
839	that all threads are killed and that there are no outstanding requests.	1040	that all threads are killed and that there are no outstanding requests.
840		1041
841	Under normal circumstances you don't need to call this function.	1042	Under normal circumstances you don't need to call this function.
842		1043
		1044	=item IO::AIO::max_idle $nthreads
		1045
		1046	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1047	threads that did not get a request to process within 10 seconds). That
		1048	means if a thread becomes idle while C<$nthreads> other threads are also
		1049	idle, it will free its resources and exit.
		1050
		1051	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1052	to allow for extremely high load situations, but want to free resources
		1053	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1054
		1055	The default is probably ok in most situations, especially if thread
		1056	creation is fast. If thread creation is very slow on your system you might
		1057	want to use larger values.
		1058
843	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1059	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
844		1060
845	[DEPRECATED]	1061	This is a very bad function to use in interactive programs because it
		1062	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1063	use an C<aio_group> together with a feed callback.
846		1064
847	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1065	Sets the maximum number of outstanding requests to C<$nreqs>. If you
848	try to queue up more than this number of requests, the caller will block until	1066	to queue up more than this number of requests, the next call to the
849	some requests have been handled.	1067	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1068	function will block until the limit is no longer exceeded.
850		1069
851	The default is very large, so normally there is no practical limit. If you	1070	The default value is very large, so there is no practical limit on the
852	queue up many requests in a loop it often improves speed if you set	1071	number of outstanding requests.
853	this to a relatively low number, such as C<100>.
854		1072
855	This function does not work well together with C<aio_group>'s, and their	1073	You can still queue as many requests as you want. Therefore,
856	feeder interface is better suited to limiting concurrency, so do not use	1074	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
857	this function.	1075	as a stop gap to shield against fatal memory overflow (with large values).
858		1076
859	Under normal circumstances you don't need to call this function.	1077	=head3 STATISTICAL INFORMATION
		1078
		1079	=item IO::AIO::nreqs
		1080
		1081	Returns the number of requests currently in the ready, execute or pending
		1082	states (i.e. for which their callback has not been invoked yet).
		1083
		1084	Example: wait till there are no outstanding requests anymore:
		1085
		1086	IO::AIO::poll_wait, IO::AIO::poll_cb
		1087	while IO::AIO::nreqs;
		1088
		1089	=item IO::AIO::nready
		1090
		1091	Returns the number of requests currently in the ready state (not yet
		1092	executed).
		1093
		1094	=item IO::AIO::npending
		1095
		1096	Returns the number of requests currently in the pending state (executed,
		1097	but not yet processed by poll_cb).
860		1098
861	=back	1099	=back
862		1100
863	=cut	1101	=cut
864		1102
…		…
878	*$sym	1116	*$sym
879	}	1117	}
880		1118
881	min_parallel 8;	1119	min_parallel 8;
882		1120
883	END {	1121	END { flush }
884	max_parallel 0;
885	}
886		1122
887	1;	1123	1;
888		1124
889	=head2 FORK BEHAVIOUR	1125	=head2 FORK BEHAVIOUR
890		1126
891	This module should do "the right thing" when the process using it forks:	1127	This module should do "the right thing" when the process using it forks:
892		1128
893	Before the fork, IO::AIO enters a quiescent state where no requests	1129	Before the fork, IO::AIO enters a quiescent state where no requests
894	can be added in other threads and no results will be processed. After	1130	can be added in other threads and no results will be processed. After
895	the fork the parent simply leaves the quiescent state and continues	1131	the fork the parent simply leaves the quiescent state and continues
896	request/result processing, while the child clears the request/result	1132	request/result processing, while the child frees the request/result queue
897	queue (so the requests started before the fork will only be handled in	1133	(so that the requests started before the fork will only be handled in the
898	the parent). Threads will be started on demand until the limit ste in the	1134	parent). Threads will be started on demand until the limit set in the
899	parent process has been reached again.	1135	parent process has been reached again.
900		1136
901	In short: the parent will, after a short pause, continue as if fork had	1137	In short: the parent will, after a short pause, continue as if fork had
902	not been called, while the child will act as if IO::AIO has not been used	1138	not been called, while the child will act as if IO::AIO has not been used
903	yet.	1139	yet.
904		1140
905	=head2 MEMORY USAGE	1141	=head2 MEMORY USAGE
906		1142
		1143	Per-request usage:
		1144
907	Each aio request uses - depending on your architecture - around 128 bytes	1145	Each aio request uses - depending on your architecture - around 100-200
908	of memory. In addition, stat requests need a stat buffer (possibly a few	1146	bytes of memory. In addition, stat requests need a stat buffer (possibly
909	hundred bytes). Perl scalars and other data passed into aio requests will	1147	a few hundred bytes), readdir requires a result buffer and so on. Perl
910	also be locked.	1148	scalars and other data passed into aio requests will also be locked and
		1149	will consume memory till the request has entered the done state.
911		1150
912	This is now awfully much, so queuing lots of requests is not usually a	1151	This is now awfully much, so queuing lots of requests is not usually a
913	problem.	1152	problem.
914		1153
915	Each thread needs a stack area which is usually around 16k, sometimes much	1154	Per-thread usage:
916	larger, depending on the OS.	1155
		1156	In the execution phase, some aio requests require more memory for
		1157	temporary buffers, and each thread requires a stack and other data
		1158	structures (usually around 16k-128k, depending on the OS).
		1159
		1160	=head1 KNOWN BUGS
		1161
		1162	Known bugs will be fixed in the next release.
917		1163
918	=head1 SEE ALSO	1164	=head1 SEE ALSO
919		1165
920	L<Coro::AIO>.	1166	L<Coro::AIO>.
921		1167

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC vs. Revision 1.97 by root, Sat Dec 23 04:49:37 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.70 by root, Tue Oct 24 03:40:38 2006 UTC vs.
Revision 1.97 by root, Sat Dec 23 04:49:37 2006 UTC