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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.22 by root, Wed Jul 20 21:55:27 2005 UTC vs.
Revision 1.42 by root, Mon Dec 26 18:15:23 2005 UTC

…		…
14	aio_unlink "/tmp/file", sub { };	14	aio_unlink "/tmp/file", sub { };
15		15
16	aio_read $fh, 30000, 1024, $buffer, 0, sub {	16	aio_read $fh, 30000, 1024, $buffer, 0, sub {
17	$_[0] > 0 or die "read error: $!";	17	$_[0] > 0 or die "read error: $!";
18	};	18	};
		19
		20	# AnyEvent
		21	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
		22	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
19		23
20	# Event	24	# Event
21	Event->io (fd => IO::AIO::poll_fileno,	25	Event->io (fd => IO::AIO::poll_fileno,
22	poll => 'r',	26	poll => 'r',
23	cb => \&IO::AIO::poll_cb);	27	cb => \&IO::AIO::poll_cb);
…		…
56		60
57	=cut	61	=cut
58		62
59	package IO::AIO;	63	package IO::AIO;
60		64
		65	no warnings;
		66
61	use base 'Exporter';	67	use base 'Exporter';
62		68
63	use Fcntl ();	69	use Fcntl ();
64		70
65	BEGIN {	71	BEGIN {
66	$VERSION = 0.9;	72	$VERSION = '1.61';
67		73
68	@EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink	74	@EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
		75	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
69	aio_fsync aio_fdatasync aio_readahead);	76	aio_fsync aio_fdatasync aio_readahead);
70	@EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	77	@EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel
		78	max_outstanding nreqs);
71		79
72	require XSLoader;	80	require XSLoader;
73	XSLoader::load IO::AIO, $VERSION;	81	XSLoader::load IO::AIO, $VERSION;
74	}	82	}
75		83
…		…
83	which must be a code reference. This code reference will get called with	91	which must be a code reference. This code reference will get called with
84	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	92	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
85	perl, which usually delivers "false") as it's sole argument when the given	93	perl, which usually delivers "false") as it's sole argument when the given
86	syscall has been executed asynchronously.	94	syscall has been executed asynchronously.
87		95
88	All functions that expect a filehandle will also accept a file descriptor.	96	All functions expecting a filehandle keep a copy of the filehandle
		97	internally until the request has finished.
89		98
90	The filenames you pass to these routines I<must> be absolute. The reason	99	The pathnames you pass to these routines I<must> be absolute and
91	for this is that at the time the request is being executed, the current	100	encoded in byte form. The reason for the former is that at the time the
92	working directory could have changed. Alternatively, you can make sure	101	request is being executed, the current working directory could have
93	that you never change the current working directory.	102	changed. Alternatively, you can make sure that you never change the
		103	current working directory.
		104
		105	To encode pathnames to byte form, either make sure you either: a)
		106	always pass in filenames you got from outside (command line, readdir
		107	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
		108	your pathnames to the locale (or other) encoding in effect in the user
		109	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
		110	use something else.
94		111
95	=over 4	112	=over 4
96		113
97	=item aio_open $pathname, $flags, $mode, $callback	114	=item aio_open $pathname, $flags, $mode, $callback->($fh)
98		115
99	Asynchronously open or create a file and call the callback with a newly	116	Asynchronously open or create a file and call the callback with a newly
100	created filehandle for the file.	117	created filehandle for the file.
101		118
102	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	119	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
…		…
119	} else {	136	} else {
120	die "open failed: $!\n";	137	die "open failed: $!\n";
121	}	138	}
122	};	139	};
123		140
124	=item aio_close $fh, $callback	141	=item aio_close $fh, $callback->($status)
125		142
126	Asynchronously close a file and call the callback with the result	143	Asynchronously close a file and call the callback with the result
127	code. I<WARNING:> although accepted, you should not pass in a perl	144	code. I<WARNING:> although accepted, you should not pass in a perl
128	filehandle here, as perl will likely close the file descriptor another	145	filehandle here, as perl will likely close the file descriptor another
129	time when the filehandle is destroyed. Normally, you can safely call perls	146	time when the filehandle is destroyed. Normally, you can safely call perls
130	C<close> or just let filehandles go out of scope.	147	C<close> or just let filehandles go out of scope.
131		148
132	This is supposed to be a bug in the API, so that might change. It's	149	This is supposed to be a bug in the API, so that might change. It's
133	therefore best to avoid this function.	150	therefore best to avoid this function.
134		151
135	=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback	152	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
136		153
137	=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback	154	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
138		155
139	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	156	Reads or writes C<length> bytes from the specified C<fh> and C<offset>
140	into the scalar given by C<data> and offset C<dataoffset> and calls the	157	into the scalar given by C<data> and offset C<dataoffset> and calls the
141	callback without the actual number of bytes read (or -1 on error, just	158	callback without the actual number of bytes read (or -1 on error, just
142	like the syscall).	159	like the syscall).
143		160
		161	The C<$data> scalar I<MUST NOT> be modified in any way while the request
		162	is outstanding. Modifying it can result in segfaults or WW3 (if the
		163	necessary/optional hardware is installed).
		164
144	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	165	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
145	offset C<0> within the scalar:	166	offset C<0> within the scalar:
146		167
147	aio_read $fh, 7, 15, $buffer, 0, sub {	168	aio_read $fh, 7, 15, $buffer, 0, sub {
148	$_[0] > 0 or die "read error: $!";	169	$_[0] > 0 or die "read error: $!";
149	print "read $_[0] bytes: <$buffer>\n";	170	print "read $_[0] bytes: <$buffer>\n";
150	};	171	};
151		172
		173	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		174
		175	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
		176	reading at byte offset C<$in_offset>, and starts writing at the current
		177	file offset of C<$out_fh>. Because of that, it is not safe to issue more
		178	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
		179	other.
		180
		181	This call tries to make use of a native C<sendfile> syscall to provide
		182	zero-copy operation. For this to work, C<$out_fh> should refer to a
		183	socket, and C<$in_fh> should refer to mmap'able file.
		184
		185	If the native sendfile call fails or is not implemented, it will be
		186	emulated, so you can call C<aio_sendfile> on any type of filehandle
		187	regardless of the limitations of the operating system.
		188
		189	Please note, however, that C<aio_sendfile> can read more bytes from
		190	C<$in_fh> than are written, and there is no way to find out how many
		191	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
		192	provides the number of bytes written to C<$out_fh>. Only if the result
		193	value equals C<$length> one can assume that C<$length> bytes have been
		194	read.
		195
152	=item aio_readahead $fh,$offset,$length, $callback	196	=item aio_readahead $fh,$offset,$length, $callback->($retval)
153
154	Asynchronously reads the specified byte range into the page cache, using
155	the C<readahead> syscall. If that syscall doesn't exist (likely if your OS
156	isn't Linux) the status will be C<-1> and C<$!> is set to C<ENOSYS>.
157		197
158	C<aio_readahead> populates the page cache with data from a file so that	198	C<aio_readahead> populates the page cache with data from a file so that
159	subsequent reads from that file will not block on disk I/O. The C<$offset>	199	subsequent reads from that file will not block on disk I/O. The C<$offset>
160	argument specifies the starting point from which data is to be read and	200	argument specifies the starting point from which data is to be read and
161	C<$length> specifies the number of bytes to be read. I/O is performed in	201	C<$length> specifies the number of bytes to be read. I/O is performed in
162	whole pages, so that offset is effectively rounded down to a page boundary	202	whole pages, so that offset is effectively rounded down to a page boundary
163	and bytes are read up to the next page boundary greater than or equal to	203	and bytes are read up to the next page boundary greater than or equal to
164	(off-set+length). C<aio_readahead> does not read beyond the end of the	204	(off-set+length). C<aio_readahead> does not read beyond the end of the
165	file. The current file offset of the file is left unchanged.	205	file. The current file offset of the file is left unchanged.
166		206
		207	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
		208	emulated by simply reading the data, which would have a similar effect.
		209
167	=item aio_stat $fh_or_path, $callback	210	=item aio_stat $fh_or_path, $callback->($status)
168		211
169	=item aio_lstat $fh, $callback	212	=item aio_lstat $fh, $callback->($status)
170		213
171	Works like perl's C<stat> or C<lstat> in void context. The callback will	214	Works like perl's C<stat> or C<lstat> in void context. The callback will
172	be called after the stat and the results will be available using C<stat _>	215	be called after the stat and the results will be available using C<stat _>
173	or C<-s _> etc...	216	or C<-s _> etc...
174		217
…		…
184	aio_stat "/etc/passwd", sub {	227	aio_stat "/etc/passwd", sub {
185	$_[0] and die "stat failed: $!";	228	$_[0] and die "stat failed: $!";
186	print "size is ", -s _, "\n";	229	print "size is ", -s _, "\n";
187	};	230	};
188		231
189	=item aio_unlink $pathname, $callback	232	=item aio_unlink $pathname, $callback->($status)
190		233
191	Asynchronously unlink (delete) a file and call the callback with the	234	Asynchronously unlink (delete) a file and call the callback with the
192	result code.	235	result code.
193		236
		237	=item aio_rmdir $pathname, $callback->($status)
		238
		239	Asynchronously rmdir (delete) a directory and call the callback with the
		240	result code.
		241
		242	=item aio_readdir $pathname $callback->($entries)
		243
		244	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
		245	directory (i.e. opendir + readdir + closedir). The entries will not be
		246	sorted, and will B<NOT> include the C<.> and C<..> entries.
		247
		248	The callback a single argument which is either C<undef> or an array-ref
		249	with the filenames.
		250
		251	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		252
		253	Scans a directory (similar to C<aio_readdir>) and tries to separate the
		254	entries of directory C<$path> into two sets of names, ones you can recurse
		255	into (directories), and ones you cannot recurse into (everything else).
		256
		257	C<aio_scandir> is a composite request that consists of many
		258	aio-primitives. C<$maxreq> specifies the maximum number of outstanding
		259	aio requests that this function generates. If it is C<< <= 0 >>, then a
		260	suitable default will be chosen (currently 8).
		261
		262	On error, the callback is called without arguments, otherwise it receives
		263	two array-refs with path-relative entry names.
		264
		265	Example:
		266
		267	aio_scandir $dir, 0, sub {
		268	my ($dirs, $nondirs) = @_;
		269	print "real directories: @$dirs\n";
		270	print "everything else: @$nondirs\n";
		271	};
		272
		273	Implementation notes.
		274
		275	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
		276
		277	After reading the directory, the modification time, size etc. of the
		278	directory before and after the readdir is checked, and if they match, the
		279	link count will be used to decide how many entries are directories (if
		280	>= 2). Otherwise, no knowledge of the number of subdirectories will be
		281	assumed.
		282
		283	Then entires will be sorted into likely directories (everything without a
		284	non-initial dot) and likely non-directories (everything else). Then every
		285	entry + C</.> will be C<stat>'ed, likely directories first. This is often
		286	faster because filesystems might detect the type of the entry without
		287	reading the inode data (e.g. ext2s filetype feature). If that succeeds,
		288	it assumes that the entry is a directory or a symlink to directory (which
		289	will be checked seperately).
		290
		291	If the known number of directories has been reached, the rest of the
		292	entries is assumed to be non-directories.
		293
		294	=cut
		295
		296	sub aio_scandir($$$) {
		297	my ($path, $maxreq, $cb) = @_;
		298
		299	$maxreq = 8 if $maxreq <= 0;
		300
		301	# stat once
		302	aio_stat $path, sub {
		303	$cb->() if $_[0];
		304	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		305
		306	# read the directory entries
		307	aio_readdir $path, sub {
		308	my $entries = shift
		309	or return $cb->();
		310
		311	# stat the dir another time
		312	aio_stat $path, sub {
		313	my $hash2 = join ":", (stat _)[0,1,3,7,9];
		314
		315	my $ndirs;
		316
		317	# take the slow route if anything looks fishy
		318	if ($hash1 ne $hash2) {
		319	$ndirs = -1;
		320	} else {
		321	# if nlink == 2, we are finished
		322	# on non-posix-fs's, we rely on nlink < 2
		323	$ndirs = (stat _)[3] - 2
		324	or $cb->([], $entries);
		325	}
		326
		327	# sort into likely dirs and likely nondirs
		328	# dirs == files without ".", short entries first
		329	$entries = [map $_->[0],
		330	sort { $b->[1] cmp $a->[1] }
		331	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
		332	@$entries];
		333
		334	my (@dirs, @nondirs);
		335
		336	my ($statcb, $schedcb);
		337	my $nreq = 0;
		338
		339	$schedcb = sub {
		340	if (@$entries) {
		341	if ($nreq < $maxreq) {
		342	my $ent = pop @$entries;
		343	$nreq++;
		344	aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
		345	}
		346	} elsif (!$nreq) {
		347	# finished
		348	undef $statcb;
		349	undef $schedcb;
		350	$cb->(\@dirs, \@nondirs);
		351	undef $cb;
		352	}
		353	};
		354	$statcb = sub {
		355	my ($status, $entry) = @_;
		356
		357	if ($status < 0) {
		358	$nreq--;
		359	push @nondirs, $entry;
		360	&$schedcb;
		361	} else {
		362	# need to check for real directory
		363	aio_lstat "$path/$entry", sub {
		364	$nreq--;
		365
		366	if (-d _) {
		367	push @dirs, $entry;
		368
		369	if (!--$ndirs) {
		370	push @nondirs, @$entries;
		371	$entries = [];
		372	}
		373	} else {
		374	push @nondirs, $entry;
		375	}
		376
		377	&$schedcb;
		378	}
		379	}
		380	};
		381
		382	&$schedcb while @$entries && $nreq < $maxreq;
		383	};
		384	};
		385	};
		386	}
		387
194	=item aio_fsync $fh, $callback	388	=item aio_fsync $fh, $callback->($status)
195		389
196	Asynchronously call fsync on the given filehandle and call the callback	390	Asynchronously call fsync on the given filehandle and call the callback
197	with the fsync result code.	391	with the fsync result code.
198		392
199	=item aio_fdatasync $fh, $callback	393	=item aio_fdatasync $fh, $callback->($status)
200		394
201	Asynchronously call fdatasync on the given filehandle and call the	395	Asynchronously call fdatasync on the given filehandle and call the
202	callback with the fdatasync result code. Might set C<$!> to C<ENOSYS> if	396	callback with the fdatasync result code.
203	C<fdatasync> is not available.	397
		398	If this call isn't available because your OS lacks it or it couldn't be
		399	detected, it will be emulated by calling C<fsync> instead.
204		400
205	=back	401	=back
206		402
207	=head2 SUPPORT FUNCTIONS	403	=head2 SUPPORT FUNCTIONS
208		404
…		…
266	IO::AIO::poll_wait, IO::AIO::poll_cb	462	IO::AIO::poll_wait, IO::AIO::poll_cb
267	if IO::AIO::nreqs;	463	if IO::AIO::nreqs;
268		464
269	=item IO::AIO::min_parallel $nthreads	465	=item IO::AIO::min_parallel $nthreads
270		466
271	Set the minimum number of AIO threads to C<$nthreads>. The default is	467	Set the minimum number of AIO threads to C<$nthreads>. The current default
272	C<1>, which means a single asynchronous operation can be done at one time	468	is C<4>, which means four asynchronous operations can be done at one time
273	(the number of outstanding operations, however, is unlimited).	469	(the number of outstanding operations, however, is unlimited).
		470
		471	IO::AIO starts threads only on demand, when an AIO request is queued and
		472	no free thread exists.
274		473
275	It is recommended to keep the number of threads low, as some Linux	474	It is recommended to keep the number of threads low, as some Linux
276	kernel versions will scale negatively with the number of threads (higher	475	kernel versions will scale negatively with the number of threads (higher
277	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	476	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
278	threads should be fine.	477	threads should be fine.
279		478
280	Under normal circumstances you don't need to call this function, as this	479	Under most circumstances you don't need to call this function, as the
281	module automatically starts some threads (the exact number might change,	480	module selects a default that is suitable for low to moderate load.
282	and is currently 4).
283		481
284	=item IO::AIO::max_parallel $nthreads	482	=item IO::AIO::max_parallel $nthreads
285		483
286	Sets the maximum number of AIO threads to C<$nthreads>. If more than	484	Sets the maximum number of AIO threads to C<$nthreads>. If more than the
287	the specified number of threads are currently running, kill them. This	485	specified number of threads are currently running, this function kills
288	function blocks until the limit is reached.	486	them. This function blocks until the limit is reached.
		487
		488	While C<$nthreads> are zero, aio requests get queued but not executed
		489	until the number of threads has been increased again.
289		490
290	This module automatically runs C<max_parallel 0> at program end, to ensure	491	This module automatically runs C<max_parallel 0> at program end, to ensure
291	that all threads are killed and that there are no outstanding requests.	492	that all threads are killed and that there are no outstanding requests.
292		493
293	Under normal circumstances you don't need to call this function.	494	Under normal circumstances you don't need to call this function.
…		…
297	Sets the maximum number of outstanding requests to C<$nreqs>. If you	498	Sets the maximum number of outstanding requests to C<$nreqs>. If you
298	try to queue up more than this number of requests, the caller will block until	499	try to queue up more than this number of requests, the caller will block until
299	some requests have been handled.	500	some requests have been handled.
300		501
301	The default is very large, so normally there is no practical limit. If you	502	The default is very large, so normally there is no practical limit. If you
302	queue up many requests in a loop it it often improves speed if you set	503	queue up many requests in a loop it often improves speed if you set
303	this to a relatively low number, such as C<100>.	504	this to a relatively low number, such as C<100>.
304		505
305	Under normal circumstances you don't need to call this function.	506	Under normal circumstances you don't need to call this function.
306		507
307	=back	508	=back
…		…
310		511
311	# support function to convert a fd into a perl filehandle	512	# support function to convert a fd into a perl filehandle
312	sub _fd2fh {	513	sub _fd2fh {
313	return undef if $_[0] < 0;	514	return undef if $_[0] < 0;
314		515
315	# try to be perl5.6-compatible	516	# try to generate nice filehandles
316	local *AIO_FH;	517	my $sym = "IO::AIO::fd#$_[0]";
317	open AIO_FH, "+<&=$_[0]"	518	local *$sym;
		519
		520	open *$sym, "+<&=$_[0]" # usually works under any unix
		521	or open *$sym, "<&=$_[0]" # cygwin needs this
		522	or open *$sym, ">&=$_[0]" # or this
318	or return undef;	523	or return undef;
319		524
320	*AIO_FH	525	*$sym
321	}	526	}
322		527
323	min_parallel 4;	528	min_parallel 4;
324		529
325	END {	530	END {
326	max_parallel 0;	531	max_parallel 0;
327	}	532	}
328		533
329	1;	534	1;
330		535
		536	=head2 FORK BEHAVIOUR
		537
		538	Before the fork, IO::AIO enters a quiescent state where no requests
		539	can be added in other threads and no results will be processed. After
		540	the fork the parent simply leaves the quiescent state and continues
		541	request/result processing, while the child clears the request/result
		542	queue (so the requests started before the fork will only be handled in
		543	the parent). Threats will be started on demand until the limit ste in the
		544	parent process has been reached again.
		545
331	=head1 SEE ALSO	546	=head1 SEE ALSO
332		547
333	L<Coro>, L<Linux::AIO>.	548	L<Coro>, L<Linux::AIO>.
334		549
335	=head1 AUTHOR	550	=head1 AUTHOR

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.22 by root, Wed Jul 20 21:55:27 2005 UTC vs. Revision 1.42 by root, Mon Dec 26 18:15:23 2005 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.22 by root, Wed Jul 20 21:55:27 2005 UTC vs.
Revision 1.42 by root, Mon Dec 26 18:15:23 2005 UTC