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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs.
Revision 1.100 by root, Sun Jan 7 21:36:58 2007 UTC

…		…
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
51	=head1 DESCRIPTION	52	=head1 DESCRIPTION
52		53
53	This module implements asynchronous I/O using whatever means your	54	This module implements asynchronous I/O using whatever means your
54	operating system supports.	55	operating system supports.
55		56
		57	Asynchronous means that operations that can normally block your program
		58	(e.g. reading from disk) will be done asynchronously: the operation
		59	will still block, but you can do something else in the meantime. This
		60	is extremely useful for programs that need to stay interactive even
		61	when doing heavy I/O (GUI programs, high performance network servers
		62	etc.), but can also be used to easily do operations in parallel that are
		63	normally done sequentially, e.g. stat'ing many files, which is much faster
		64	on a RAID volume or over NFS when you do a number of stat operations
		65	concurrently.
		66
		67	While most of this works on all types of file descriptors (for example
		68	sockets), using these functions on file descriptors that support
		69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or
		70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop
		71	for that (such as the L<Event\|Event> module): IO::AIO will naturally fit
		72	into such an event loop itself.
		73
56	Currently, a number of threads are started that execute your read/writes	74	In this version, a number of threads are started that execute your
57	and signal their completion. You don't need thread support in perl, and	75	requests and signal their completion. You don't need thread support
58	the threads created by this module will not be visible to perl. In the	76	in perl, and the threads created by this module will not be visible
59	future, this module might make use of the native aio functions available	77	to perl. In the future, this module might make use of the native aio
60	on many operating systems. However, they are often not well-supported	78	functions available on many operating systems. However, they are often
61	(Linux doesn't allow them on normal files currently, for example),	79	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	and they would only support aio_read and aio_write, so the remaining	80	files currently, for example), and they would only support aio_read and
63	functionality would have to be implemented using threads anyway.	81	aio_write, so the remaining functionality would have to be implemented
		82	using threads anyway.
64		83
65	Although the module will work with in the presence of other threads,	84	Although the module will work with in the presence of other (Perl-)
66	it is currently not reentrant in any way, so use appropriate locking	85	threads, it is currently not reentrant in any way, so use appropriate
67	yourself, always call C<poll_cb> from within the same thread, or never	86	locking yourself, always call C<poll_cb> from within the same thread, or
68	call C<poll_cb> (or other C<aio_> functions) recursively.	87	never call C<poll_cb> (or other C<aio_> functions) recursively.
		88
		89	=head2 EXAMPLE
		90
		91	This is a simple example that uses the Event module and loads
		92	F</etc/passwd> asynchronously:
		93
		94	use Fcntl;
		95	use Event;
		96	use IO::AIO;
		97
		98	# register the IO::AIO callback with Event
		99	Event->io (fd => IO::AIO::poll_fileno,
		100	poll => 'r',
		101	cb => \&IO::AIO::poll_cb);
		102
		103	# queue the request to open /etc/passwd
		104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		105	my $fh = shift
		106	or die "error while opening: $!";
		107
		108	# stat'ing filehandles is generally non-blocking
		109	my $size = -s $fh;
		110
		111	# queue a request to read the file
		112	my $contents;
		113	aio_read $fh, 0, $size, $contents, 0, sub {
		114	$_[0] == $size
		115	or die "short read: $!";
		116
		117	close $fh;
		118
		119	# file contents now in $contents
		120	print $contents;
		121
		122	# exit event loop and program
		123	Event::unloop;
		124	};
		125	};
		126
		127	# possibly queue up other requests, or open GUI windows,
		128	# check for sockets etc. etc.
		129
		130	# process events as long as there are some:
		131	Event::loop;
		132
		133	=head1 REQUEST ANATOMY AND LIFETIME
		134
		135	Every C<aio_*> function creates a request. which is a C data structure not
		136	directly visible to Perl.
		137
		138	If called in non-void context, every request function returns a Perl
		139	object representing the request. In void context, nothing is returned,
		140	which saves a bit of memory.
		141
		142	The perl object is a fairly standard ref-to-hash object. The hash contents
		143	are not used by IO::AIO so you are free to store anything you like in it.
		144
		145	During their existance, aio requests travel through the following states,
		146	in order:
		147
		148	=over 4
		149
		150	=item ready
		151
		152	Immediately after a request is created it is put into the ready state,
		153	waiting for a thread to execute it.
		154
		155	=item execute
		156
		157	A thread has accepted the request for processing and is currently
		158	executing it (e.g. blocking in read).
		159
		160	=item pending
		161
		162	The request has been executed and is waiting for result processing.
		163
		164	While request submission and execution is fully asynchronous, result
		165	processing is not and relies on the perl interpreter calling C<poll_cb>
		166	(or another function with the same effect).
		167
		168	=item result
		169
		170	The request results are processed synchronously by C<poll_cb>.
		171
		172	The C<poll_cb> function will process all outstanding aio requests by
		173	calling their callbacks, freeing memory associated with them and managing
		174	any groups they are contained in.
		175
		176	=item done
		177
		178	Request has reached the end of its lifetime and holds no resources anymore
		179	(except possibly for the Perl object, but its connection to the actual
		180	aio request is severed and calling its methods will either do nothing or
		181	result in a runtime error).
		182
		183	=back
69		184
70	=cut	185	=cut
71		186
72	package IO::AIO;	187	package IO::AIO;
73		188
…		…
75	use strict 'vars';	190	use strict 'vars';
76		191
77	use base 'Exporter';	192	use base 'Exporter';
78		193
79	BEGIN {	194	BEGIN {
80	our $VERSION = '2.0';	195	our $VERSION = '2.32';
81		196
82	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	197	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
83	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	198	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
84	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	199	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
85	aio_group aio_nop);	200	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree);
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	Try to move the I<file> (directories not supported as either source or
219	destination) from C<$srcpath> to C<$dstpath> and call the callback with
220	the C<0> (error) or C<-1> ok.
221
222	This is a composite request that tries to rename(2) the file first. If
223	rename files with C<EXDEV>, it creates the destination file with mode 0200
224	and copies the contents of the source file into it using C<aio_sendfile>,
225	followed by restoring atime, mtime, access mode and uid/gid, in that
226	order, and unlinking the C<$srcpath>.
227
228	If an error occurs, the partial destination file will be unlinked, if
229	possible, except when setting atime, mtime, access mode and uid/gid, where
230	errors are being ignored.
231
232	=cut
233
234	sub aio_move($$$) {
235	my ($src, $dst, $cb) = @_;
236
237	my $grp = aio_group $cb;
238
239	add $grp aio_rename $src, $dst, sub {
240	if ($_[0] && $! == EXDEV) {
241	add $grp aio_open $src, O_RDONLY, 0, sub {
242	if (my $src_fh = $_[0]) {
243	my @stat = stat $src_fh;
244
245	add $grp aio_open $dst, O_WRONLY, 0200, sub {
246	if (my $dst_fh = $_[0]) {
247	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
248	close $src_fh;
249
250	if ($_[0] == $stat[7]) {
251	utime $stat[8], $stat[9], $dst;
252	chmod $stat[2] & 07777, $dst_fh;
253	chown $stat[4], $stat[5], $dst_fh;
254	close $dst_fh;
255
256	add $grp aio_unlink $src, sub {
257	$grp->result ($_[0]);
258	};
259	} else {
260	my $errno = $!;
261	add $grp aio_unlink $dst, sub {
262	$! = $errno;
263	$grp->result (-1);
264	};
265	}
266	};
267	} else {
268	$grp->result (-1);
269	}
270	},
271
272	} else {
273	$grp->result (-1);
274	}
275	};
276	} else {
277	$grp->result ($_[0]);
278	}
279	};
280
281	$grp
282	}
283
284	=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)
285		341
286	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
287	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
288	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
…		…
343	=item aio_unlink $pathname, $callback->($status)	399	=item aio_unlink $pathname, $callback->($status)
344		400
345	Asynchronously unlink (delete) a file and call the callback with the	401	Asynchronously unlink (delete) a file and call the callback with the
346	result code.	402	result code.
347		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
348	=item aio_link $srcpath, $dstpath, $callback->($status)	414	=item aio_link $srcpath, $dstpath, $callback->($status)
349		415
350	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
351	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.
352		418
353	=item aio_symlink $srcpath, $dstpath, $callback->($status)	419	=item aio_symlink $srcpath, $dstpath, $callback->($status)
354		420
355	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
356	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.
357		429
358	=item aio_rename $srcpath, $dstpath, $callback->($status)	430	=item aio_rename $srcpath, $dstpath, $callback->($status)
359		431
360	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
361	rename(2) and call the callback with the result code.	433	rename(2) and call the callback with the result code.
…		…
372	sorted, and will B<NOT> include the C<.> and C<..> entries.	444	sorted, and will B<NOT> include the C<.> and C<..> entries.
373		445
374	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
375	with the filenames.	447	with the filenames.
376		448
		449	=item aio_load $path, $data, $callback->($status)
		450
		451	This is a composite request that tries to fully load the given file into
		452	memory. Status is the same as with aio_read.
		453
		454	=cut
		455
		456	sub aio_load($$;$) {
		457	aio_block {
		458	my ($path, undef, $cb) = @_;
		459	my $data = \$_[1];
		460
		461	my $pri = aioreq_pri;
		462	my $grp = aio_group $cb;
		463
		464	aioreq_pri $pri;
		465	add $grp aio_open $path, O_RDONLY, 0, sub {
		466	my ($fh) = @_
		467	or return $grp->result (-1);
		468
		469	aioreq_pri $pri;
		470	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		471	$grp->result ($_[0]);
		472	};
		473	};
		474
		475	$grp
		476	}
		477	}
		478
		479	=item aio_copy $srcpath, $dstpath, $callback->($status)
		480
		481	Try to copy the I<file> (directories not supported as either source or
		482	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		483	the C<0> (error) or C<-1> ok.
		484
		485	This is a composite request that it creates the destination file with
		486	mode 0200 and copies the contents of the source file into it using
		487	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		488	uid/gid, in that order.
		489
		490	If an error occurs, the partial destination file will be unlinked, if
		491	possible, except when setting atime, mtime, access mode and uid/gid, where
		492	errors are being ignored.
		493
		494	=cut
		495
		496	sub aio_copy($$;$) {
		497	aio_block {
		498	my ($src, $dst, $cb) = @_;
		499
		500	my $pri = aioreq_pri;
		501	my $grp = aio_group $cb;
		502
		503	aioreq_pri $pri;
		504	add $grp aio_open $src, O_RDONLY, 0, sub {
		505	if (my $src_fh = $_[0]) {
		506	my @stat = stat $src_fh;
		507
		508	aioreq_pri $pri;
		509	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		510	if (my $dst_fh = $_[0]) {
		511	aioreq_pri $pri;
		512	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		513	if ($_[0] == $stat[7]) {
		514	$grp->result (0);
		515	close $src_fh;
		516
		517	# those should not normally block. should. should.
		518	utime $stat[8], $stat[9], $dst;
		519	chmod $stat[2] & 07777, $dst_fh;
		520	chown $stat[4], $stat[5], $dst_fh;
		521	close $dst_fh;
		522	} else {
		523	$grp->result (-1);
		524	close $src_fh;
		525	close $dst_fh;
		526
		527	aioreq $pri;
		528	add $grp aio_unlink $dst;
		529	}
		530	};
		531	} else {
		532	$grp->result (-1);
		533	}
		534	},
		535
		536	} else {
		537	$grp->result (-1);
		538	}
		539	};
		540
		541	$grp
		542	}
		543	}
		544
		545	=item aio_move $srcpath, $dstpath, $callback->($status)
		546
		547	Try to move the I<file> (directories not supported as either source or
		548	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		549	the C<0> (error) or C<-1> ok.
		550
		551	This is a composite request that tries to rename(2) the file first. If
		552	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		553	that is successful, unlinking the C<$srcpath>.
		554
		555	=cut
		556
		557	sub aio_move($$;$) {
		558	aio_block {
		559	my ($src, $dst, $cb) = @_;
		560
		561	my $pri = aioreq_pri;
		562	my $grp = aio_group $cb;
		563
		564	aioreq_pri $pri;
		565	add $grp aio_rename $src, $dst, sub {
		566	if ($_[0] && $! == EXDEV) {
		567	aioreq_pri $pri;
		568	add $grp aio_copy $src, $dst, sub {
		569	$grp->result ($_[0]);
		570
		571	if (!$_[0]) {
		572	aioreq_pri $pri;
		573	add $grp aio_unlink $src;
		574	}
		575	};
		576	} else {
		577	$grp->result ($_[0]);
		578	}
		579	};
		580
		581	$grp
		582	}
		583	}
		584
377	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	585	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
378		586
379	Scans a directory (similar to C<aio_readdir>) but additionally tries to	587	Scans a directory (similar to C<aio_readdir>) but additionally tries to
380	separate the entries of directory C<$path> into two sets of names, ones	588	efficiently separate the entries of directory C<$path> into two sets of
381	you can recurse into (directories or links to them), and ones you cannot	589	names, directories you can recurse into (directories), and ones you cannot
382	recurse into (everything else).	590	recurse into (everything else, including symlinks to directories).
383		591
384	C<aio_scandir> is a composite request that creates of many sub requests_	592	C<aio_scandir> is a composite request that creates of many sub requests_
385	C<$maxreq> specifies the maximum number of outstanding aio requests that	593	C<$maxreq> specifies the maximum number of outstanding aio requests that
386	this function generates. If it is C<< <= 0 >>, then a suitable default	594	this function generates. If it is C<< <= 0 >>, then a suitable default
387	will be chosen (currently 6).	595	will be chosen (currently 4).
388		596
389	On error, the callback is called without arguments, otherwise it receives	597	On error, the callback is called without arguments, otherwise it receives
390	two array-refs with path-relative entry names.	598	two array-refs with path-relative entry names.
391		599
392	Example:	600	Example:
…		…
426	as those tend to return 0 or 1 as link counts, which disables the	634	as those tend to return 0 or 1 as link counts, which disables the
427	directory counting heuristic.	635	directory counting heuristic.
428		636
429	=cut	637	=cut
430		638
431	sub aio_scandir($$$) {	639	sub aio_scandir($$;$) {
		640	aio_block {
432	my ($path, $maxreq, $cb) = @_;	641	my ($path, $maxreq, $cb) = @_;
433		642
		643	my $pri = aioreq_pri;
		644
434	my $grp = aio_group $cb;	645	my $grp = aio_group $cb;
435		646
436	$maxreq = 6 if $maxreq <= 0;	647	$maxreq = 4 if $maxreq <= 0;
437		648
438	# stat once	649	# stat once
		650	aioreq_pri $pri;
439	add $grp aio_stat $path, sub {	651	add $grp aio_stat $path, sub {
440	return $grp->result () if $_[0];	652	return $grp->result () if $_[0];
441	my $now = time;	653	my $now = time;
442	my $hash1 = join ":", (stat _)[0,1,3,7,9];	654	my $hash1 = join ":", (stat _)[0,1,3,7,9];
443		655
444	# read the directory entries	656	# read the directory entries
		657	aioreq_pri $pri;
445	add $grp aio_readdir $path, sub {	658	add $grp aio_readdir $path, sub {
446	my $entries = shift	659	my $entries = shift
447	or return $grp->result ();	660	or return $grp->result ();
448		661
449	# stat the dir another time	662	# stat the dir another time
		663	aioreq_pri $pri;
450	add $grp aio_stat $path, sub {	664	add $grp aio_stat $path, sub {
451	my $hash2 = join ":", (stat _)[0,1,3,7,9];	665	my $hash2 = join ":", (stat _)[0,1,3,7,9];
452		666
453	my $ndirs;	667	my $ndirs;
454		668
455	# take the slow route if anything looks fishy	669	# take the slow route if anything looks fishy
456	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	670	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
457	$ndirs = -1;	671	$ndirs = -1;
458	} else {	672	} else {
459	# if nlink == 2, we are finished	673	# if nlink == 2, we are finished
460	# on non-posix-fs's, we rely on nlink < 2	674	# on non-posix-fs's, we rely on nlink < 2
461	$ndirs = (stat _)[3] - 2	675	$ndirs = (stat _)[3] - 2
462	or return $grp->result ([], $entries);	676	or return $grp->result ([], $entries);
463	}	677	}
464		678
465	# sort into likely dirs and likely nondirs	679	# sort into likely dirs and likely nondirs
466	# dirs == files without ".", short entries first	680	# dirs == files without ".", short entries first
467	$entries = [map $_->[0],	681	$entries = [map $_->[0],
468	sort { $b->[1] cmp $a->[1] }	682	sort { $b->[1] cmp $a->[1] }
469	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	683	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
470	@$entries];	684	@$entries];
471		685
472	my (@dirs, @nondirs);	686	my (@dirs, @nondirs);
473		687
474	my ($statcb, $schedcb);
475	my $nreq = 0;
476
477	my $statgrp = add $grp aio_group;	688	my $statgrp = add $grp aio_group sub {
478
479	$schedcb = sub {
480	if (@$entries) {
481	if ($nreq < $maxreq) {
482	my $ent = pop @$entries;
483	$nreq++;
484	add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
485	}
486	} elsif (!$nreq) {
487	# finished
488	$statgrp->cancel;
489	undef $statcb;
490	undef $schedcb;
491	$grp->result (\@dirs, \@nondirs);	689	$grp->result (\@dirs, \@nondirs);
492	}	690	};
		691
		692	limit $statgrp $maxreq;
		693	feed $statgrp sub {
		694	return unless @$entries;
		695	my $entry = pop @$entries;
		696
		697	aioreq_pri $pri;
		698	add $statgrp aio_stat "$path/$entry/.", sub {
		699	if ($_[0] < 0) {
		700	push @nondirs, $entry;
		701	} else {
		702	# need to check for real directory
		703	aioreq_pri $pri;
		704	add $statgrp aio_lstat "$path/$entry", sub {
		705	if (-d _) {
		706	push @dirs, $entry;
		707
		708	unless (--$ndirs) {
		709	push @nondirs, @$entries;
		710	feed $statgrp;
		711	}
		712	} else {
		713	push @nondirs, $entry;
		714	}
		715	}
		716	}
		717	};
		718	};
493	};	719	};
494	$statcb = sub {
495	my ($status, $entry) = @_;
496
497	if ($status < 0) {
498	$nreq--;
499	push @nondirs, $entry;
500	&$schedcb;
501	} else {
502	# need to check for real directory
503	add $grp aio_lstat "$path/$entry", sub {
504	$nreq--;
505
506	if (-d _) {
507	push @dirs, $entry;
508
509	if (!--$ndirs) {
510	push @nondirs, @$entries;
511	$entries = [];
512	}
513	} else {
514	push @nondirs, $entry;
515	}
516
517	&$schedcb;
518	}
519	}
520	};
521
522	&$schedcb while @$entries && $nreq < $maxreq;
523	};	720	};
524	};	721	};
		722
		723	$grp
525	};	724	}
		725	}
526		726
		727	=item aio_rmtree $path, $callback->($status)
		728
		729	Delete a directory tree starting (and including) C<$path>, return the
		730	status of the final C<rmdir> only. This is a composite request that
		731	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		732	everything else.
		733
		734	=cut
		735
		736	sub aio_rmtree;
		737	sub aio_rmtree($;$) {
		738	aio_block {
		739	my ($path, $cb) = @_;
		740
		741	my $pri = aioreq_pri;
		742	my $grp = aio_group $cb;
		743
		744	aioreq_pri $pri;
		745	add $grp aio_scandir $path, 0, sub {
		746	my ($dirs, $nondirs) = @_;
		747
		748	my $dirgrp = aio_group sub {
		749	add $grp aio_rmdir $path, sub {
		750	$grp->result ($_[0]);
		751	};
		752	};
		753
		754	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		755	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		756
		757	add $grp $dirgrp;
		758	};
		759
527	$grp	760	$grp
		761	}
528	}	762	}
529		763
530	=item aio_fsync $fh, $callback->($status)	764	=item aio_fsync $fh, $callback->($status)
531		765
532	Asynchronously call fsync on the given filehandle and call the callback	766	Asynchronously call fsync on the given filehandle and call the callback
…		…
539		773
540	If this call isn't available because your OS lacks it or it couldn't be	774	If this call isn't available because your OS lacks it or it couldn't be
541	detected, it will be emulated by calling C<fsync> instead.	775	detected, it will be emulated by calling C<fsync> instead.
542		776
543	=item aio_group $callback->(...)	777	=item aio_group $callback->(...)
544
545	[EXPERIMENTAL]
546		778
547	This is a very special aio request: Instead of doing something, it is a	779	This is a very special aio request: Instead of doing something, it is a
548	container for other aio requests, which is useful if you want to bundle	780	container for other aio requests, which is useful if you want to bundle
549	many requests into a single, composite, request with a definite callback	781	many requests into a single, composite, request with a definite callback
550	and the ability to cancel the whole request with its subrequests.	782	and the ability to cancel the whole request with its subrequests.
…		…
591	=head2 IO::AIO::REQ CLASS	823	=head2 IO::AIO::REQ CLASS
592		824
593	All non-aggregate C<aio_*> functions return an object of this class when	825	All non-aggregate C<aio_*> functions return an object of this class when
594	called in non-void context.	826	called in non-void context.
595		827
596	A request always moves through the following five states in its lifetime,
597	in order: B<ready> (request has been created, but has not been executed
598	yet), B<execute> (request is currently being executed), B<pending>
599	(request has been executed but callback has not been called yet),
600	B<result> (results are being processed synchronously, includes calling the
601	callback) and B<done> (request has reached the end of its lifetime and
602	holds no resources anymore).
603
604	=over 4	828	=over 4
605		829
606	=item cancel $req	830	=item cancel $req
607		831
608	Cancels the request, if possible. Has the effect of skipping execution	832	Cancels the request, if possible. Has the effect of skipping execution
…		…
661	=item * They can also can also be added to other IO::AIO::GRP objects.	885	=item * They can also can also be added to other IO::AIO::GRP objects.
662		886
663	=item * You must not add requests to a group from within the group callback (or	887	=item * You must not add requests to a group from within the group callback (or
664	any later time).	888	any later time).
665		889
666	=item * This does not harmonise well with C<max_outstanding>, so best do
667	not combine C<aio_group> with it. Groups and feeders are recommended for
668	this kind of concurrency-limiting.
669
670	=back	890	=back
671		891
672	Their lifetime, simplified, looks like this: when they are empty, they	892	Their lifetime, simplified, looks like this: when they are empty, they
673	will finish very quickly. If they contain only requests that are in the	893	will finish very quickly. If they contain only requests that are in the
674	C<done> state, they will also finish. Otherwise they will continue to	894	C<done> state, they will also finish. Otherwise they will continue to
…		…
689	be added, including other groups, as long as you do not create circular	909	be added, including other groups, as long as you do not create circular
690	dependencies.	910	dependencies.
691		911
692	Returns all its arguments.	912	Returns all its arguments.
693		913
		914	=item $grp->cancel_subs
		915
		916	Cancel all subrequests and clears any feeder, but not the group request
		917	itself. Useful when you queued a lot of events but got a result early.
		918
694	=item $grp->result (...)	919	=item $grp->result (...)
695		920
696	Set the result value(s) that will be passed to the group callback when all	921	Set the result value(s) that will be passed to the group callback when all
697	subrequests have finished. By default, no argument will be passed.	922	subrequests have finished and set thre groups errno to the current value
		923	of errno (just like calling C<errno> without an error number). By default,
		924	no argument will be passed and errno is zero.
		925
		926	=item $grp->errno ([$errno])
		927
		928	Sets the group errno value to C<$errno>, or the current value of errno
		929	when the argument is missing.
		930
		931	Every aio request has an associated errno value that is restored when
		932	the callback is invoked. This method lets you change this value from its
		933	default (0).
		934
		935	Calling C<result> will also set errno, so make sure you either set C<$!>
		936	before the call to C<result>, or call c<errno> after it.
698		937
699	=item feed $grp $callback->($grp)	938	=item feed $grp $callback->($grp)
700
701	[VERY EXPERIMENTAL]
702		939
703	Sets a feeder/generator on this group: every group can have an attached	940	Sets a feeder/generator on this group: every group can have an attached
704	generator that generates requests if idle. The idea behind this is that,	941	generator that generates requests if idle. The idea behind this is that,
705	although you could just queue as many requests as you want in a group,	942	although you could just queue as many requests as you want in a group,
706	this might starve other requests for a potentially long time. For	943	this might starve other requests for a potentially long time. For
…		…
743		980
744	=back	981	=back
745		982
746	=head2 SUPPORT FUNCTIONS	983	=head2 SUPPORT FUNCTIONS
747		984
		985	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		986
748	=over 4	987	=over 4
749		988
750	=item $fileno = IO::AIO::poll_fileno	989	=item $fileno = IO::AIO::poll_fileno
751		990
752	Return the I<request result pipe file descriptor>. This filehandle must be	991	Return the I<request result pipe file descriptor>. This filehandle must be
…		…
756		995
757	See C<poll_cb> for an example.	996	See C<poll_cb> for an example.
758		997
759	=item IO::AIO::poll_cb	998	=item IO::AIO::poll_cb
760		999
761	Process all outstanding events on the result pipe. You have to call this	1000	Process some outstanding events on the result pipe. You have to call this
762	regularly. Returns the number of events processed. Returns immediately	1001	regularly. Returns the number of events processed. Returns immediately
763	when no events are outstanding.	1002	when no events are outstanding. The amount of events processed depends on
		1003	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		1004
		1005	If not all requests were processed for whatever reason, the filehandle
		1006	will still be ready when C<poll_cb> returns.
764		1007
765	Example: Install an Event watcher that automatically calls	1008	Example: Install an Event watcher that automatically calls
766	IO::AIO::poll_cb with high priority:	1009	IO::AIO::poll_cb with high priority:
767		1010
768	Event->io (fd => IO::AIO::poll_fileno,	1011	Event->io (fd => IO::AIO::poll_fileno,
769	poll => 'r', async => 1,	1012	poll => 'r', async => 1,
770	cb => \&IO::AIO::poll_cb);	1013	cb => \&IO::AIO::poll_cb);
771		1014
		1015	=item IO::AIO::max_poll_reqs $nreqs
		1016
		1017	=item IO::AIO::max_poll_time $seconds
		1018
		1019	These set the maximum number of requests (default C<0>, meaning infinity)
		1020	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1021	the maximum amount of time (default C<0>, meaning infinity) spent in
		1022	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1023	of time C<poll_cb> is allowed to use).
		1024
		1025	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1026	syscall per request processed, which is not normally a problem unless your
		1027	callbacks are really really fast or your OS is really really slow (I am
		1028	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1029
		1030	Setting these is useful if you want to ensure some level of
		1031	interactiveness when perl is not fast enough to process all requests in
		1032	time.
		1033
		1034	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
		1035
		1036	Example: Install an Event watcher that automatically calls
		1037	IO::AIO::poll_cb with low priority, to ensure that other parts of the
		1038	program get the CPU sometimes even under high AIO load.
		1039
		1040	# try not to spend much more than 0.1s in poll_cb
		1041	IO::AIO::max_poll_time 0.1;
		1042
		1043	# use a low priority so other tasks have priority
		1044	Event->io (fd => IO::AIO::poll_fileno,
		1045	poll => 'r', nice => 1,
		1046	cb => &IO::AIO::poll_cb);
		1047
772	=item IO::AIO::poll_wait	1048	=item IO::AIO::poll_wait
773		1049
		1050	If there are any outstanding requests and none of them in the result
774	Wait till the result filehandle becomes ready for reading (simply does a	1051	phase, wait till the result filehandle becomes ready for reading (simply
775	C<select> on the filehandle. This is useful if you want to synchronously wait	1052	does a C<select> on the filehandle. This is useful if you want to
776	for some requests to finish).	1053	synchronously wait for some requests to finish).
777		1054
778	See C<nreqs> for an example.	1055	See C<nreqs> for an example.
779		1056
		1057	=item IO::AIO::poll
		1058
		1059	Waits until some requests have been handled.
		1060
		1061	Returns the number of requests processed, but is otherwise strictly
		1062	equivalent to:
		1063
		1064	IO::AIO::poll_wait, IO::AIO::poll_cb
		1065
780	=item IO::AIO::nreqs	1066	=item IO::AIO::flush
781		1067
782	Returns the number of requests currently outstanding (i.e. for which their	1068	Wait till all outstanding AIO requests have been handled.
783	callback has not been invoked yet).
784		1069
785	Example: wait till there are no outstanding requests anymore:	1070	Strictly equivalent to:
786		1071
787	IO::AIO::poll_wait, IO::AIO::poll_cb	1072	IO::AIO::poll_wait, IO::AIO::poll_cb
788	while IO::AIO::nreqs;	1073	while IO::AIO::nreqs;
789		1074
790	=item IO::AIO::flush	1075	=head3 CONTROLLING THE NUMBER OF THREADS
791
792	Wait till all outstanding AIO requests have been handled.
793
794	Strictly equivalent to:
795
796	IO::AIO::poll_wait, IO::AIO::poll_cb
797	while IO::AIO::nreqs;
798
799	=item IO::AIO::poll
800
801	Waits until some requests have been handled.
802
803	Strictly equivalent to:
804
805	IO::AIO::poll_wait, IO::AIO::poll_cb
806	if IO::AIO::nreqs;
807		1076
808	=item IO::AIO::min_parallel $nthreads	1077	=item IO::AIO::min_parallel $nthreads
809		1078
810	Set the minimum number of AIO threads to C<$nthreads>. The current	1079	Set the minimum number of AIO threads to C<$nthreads>. The current
811	default is C<8>, which means eight asynchronous operations can execute	1080	default is C<8>, which means eight asynchronous operations can execute
812	concurrently at any one time (the number of outstanding requests,	1081	concurrently at any one time (the number of outstanding requests,
813	however, is unlimited).	1082	however, is unlimited).
814		1083
815	IO::AIO starts threads only on demand, when an AIO request is queued and	1084	IO::AIO starts threads only on demand, when an AIO request is queued and
816	no free thread exists.	1085	no free thread exists. Please note that queueing up a hundred requests can
		1086	create demand for a hundred threads, even if it turns out that everything
		1087	is in the cache and could have been processed faster by a single thread.
817		1088
818	It is recommended to keep the number of threads relatively low, as some	1089	It is recommended to keep the number of threads relatively low, as some
819	Linux kernel versions will scale negatively with the number of threads	1090	Linux kernel versions will scale negatively with the number of threads
820	(higher parallelity => MUCH higher latency). With current Linux 2.6	1091	(higher parallelity => MUCH higher latency). With current Linux 2.6
821	versions, 4-32 threads should be fine.	1092	versions, 4-32 threads should be fine.
…		…
835	This module automatically runs C<max_parallel 0> at program end, to ensure	1106	This module automatically runs C<max_parallel 0> at program end, to ensure
836	that all threads are killed and that there are no outstanding requests.	1107	that all threads are killed and that there are no outstanding requests.
837		1108
838	Under normal circumstances you don't need to call this function.	1109	Under normal circumstances you don't need to call this function.
839		1110
		1111	=item IO::AIO::max_idle $nthreads
		1112
		1113	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1114	threads that did not get a request to process within 10 seconds). That
		1115	means if a thread becomes idle while C<$nthreads> other threads are also
		1116	idle, it will free its resources and exit.
		1117
		1118	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1119	to allow for extremely high load situations, but want to free resources
		1120	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1121
		1122	The default is probably ok in most situations, especially if thread
		1123	creation is fast. If thread creation is very slow on your system you might
		1124	want to use larger values.
		1125
840	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1126	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
841		1127
842	[DEPRECATED]	1128	This is a very bad function to use in interactive programs because it
		1129	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1130	use an C<aio_group> together with a feed callback.
843		1131
844	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1132	Sets the maximum number of outstanding requests to C<$nreqs>. If you
845	try to queue up more than this number of requests, the caller will block until	1133	to queue up more than this number of requests, the next call to the
846	some requests have been handled.	1134	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1135	function will block until the limit is no longer exceeded.
847		1136
848	The default is very large, so normally there is no practical limit. If you	1137	The default value is very large, so there is no practical limit on the
849	queue up many requests in a loop it often improves speed if you set	1138	number of outstanding requests.
850	this to a relatively low number, such as C<100>.
851		1139
852	This function does not work well together with C<aio_group>'s, and their	1140	You can still queue as many requests as you want. Therefore,
853	feeder interface is better suited to limiting concurrency, so do not use	1141	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
854	this function.	1142	as a stop gap to shield against fatal memory overflow (with large values).
855		1143
856	Under normal circumstances you don't need to call this function.	1144	=head3 STATISTICAL INFORMATION
		1145
		1146	=item IO::AIO::nreqs
		1147
		1148	Returns the number of requests currently in the ready, execute or pending
		1149	states (i.e. for which their callback has not been invoked yet).
		1150
		1151	Example: wait till there are no outstanding requests anymore:
		1152
		1153	IO::AIO::poll_wait, IO::AIO::poll_cb
		1154	while IO::AIO::nreqs;
		1155
		1156	=item IO::AIO::nready
		1157
		1158	Returns the number of requests currently in the ready state (not yet
		1159	executed).
		1160
		1161	=item IO::AIO::npending
		1162
		1163	Returns the number of requests currently in the pending state (executed,
		1164	but not yet processed by poll_cb).
857		1165
858	=back	1166	=back
859		1167
860	=cut	1168	=cut
861		1169
…		…
875	*$sym	1183	*$sym
876	}	1184	}
877		1185
878	min_parallel 8;	1186	min_parallel 8;
879		1187
880	END {	1188	END { flush }
881	max_parallel 0;
882	}
883		1189
884	1;	1190	1;
885		1191
886	=head2 FORK BEHAVIOUR	1192	=head2 FORK BEHAVIOUR
887		1193
888	This module should do "the right thing" when the process using it forks:	1194	This module should do "the right thing" when the process using it forks:
889		1195
890	Before the fork, IO::AIO enters a quiescent state where no requests	1196	Before the fork, IO::AIO enters a quiescent state where no requests
891	can be added in other threads and no results will be processed. After	1197	can be added in other threads and no results will be processed. After
892	the fork the parent simply leaves the quiescent state and continues	1198	the fork the parent simply leaves the quiescent state and continues
893	request/result processing, while the child clears the request/result	1199	request/result processing, while the child frees the request/result queue
894	queue (so the requests started before the fork will only be handled in	1200	(so that the requests started before the fork will only be handled in the
895	the parent). Threads will be started on demand until the limit ste in the	1201	parent). Threads will be started on demand until the limit set in the
896	parent process has been reached again.	1202	parent process has been reached again.
897		1203
898	In short: the parent will, after a short pause, continue as if fork had	1204	In short: the parent will, after a short pause, continue as if fork had
899	not been called, while the child will act as if IO::AIO has not been used	1205	not been called, while the child will act as if IO::AIO has not been used
900	yet.	1206	yet.
901		1207
902	=head2 MEMORY USAGE	1208	=head2 MEMORY USAGE
903		1209
		1210	Per-request usage:
		1211
904	Each aio request uses - depending on your architecture - around 128 bytes	1212	Each aio request uses - depending on your architecture - around 100-200
905	of memory. In addition, stat requests need a stat buffer (possibly a few	1213	bytes of memory. In addition, stat requests need a stat buffer (possibly
906	hundred bytes). Perl scalars and other data passed into aio requests will	1214	a few hundred bytes), readdir requires a result buffer and so on. Perl
907	also be locked.	1215	scalars and other data passed into aio requests will also be locked and
		1216	will consume memory till the request has entered the done state.
908		1217
909	This is now awfully much, so queuing lots of requests is not usually a	1218	This is now awfully much, so queuing lots of requests is not usually a
910	problem.	1219	problem.
911		1220
912	Each thread needs a stack area which is usually around 16k, sometimes much	1221	Per-thread usage:
913	larger, depending on the OS.	1222
		1223	In the execution phase, some aio requests require more memory for
		1224	temporary buffers, and each thread requires a stack and other data
		1225	structures (usually around 16k-128k, depending on the OS).
		1226
		1227	=head1 KNOWN BUGS
		1228
		1229	Known bugs will be fixed in the next release.
914		1230
915	=head1 SEE ALSO	1231	=head1 SEE ALSO
916		1232
917	L<Coro::AIO>.	1233	L<Coro::AIO>.
918		1234

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs. Revision 1.100 by root, Sun Jan 7 21:36:58 2007 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.71 by root, Tue Oct 24 11:57:30 2006 UTC vs.
Revision 1.100 by root, Sun Jan 7 21:36:58 2007 UTC