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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.26 by root, Sun Aug 7 03:34:07 2005 UTC vs.
Revision 1.40 by root, Tue Aug 30 15:45:10 2005 UTC

…		…
63	use base 'Exporter';	63	use base 'Exporter';
64		64
65	use Fcntl ();	65	use Fcntl ();
66		66
67	BEGIN {	67	BEGIN {
68	$VERSION = 1.1;	68	$VERSION = 1.6;
69		69
70	@EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink	70	@EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
		71	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
71	aio_fsync aio_fdatasync aio_readahead);	72	aio_fsync aio_fdatasync aio_readahead);
72	@EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	73	@EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel
		74	max_outstanding nreqs);
73		75
74	require XSLoader;	76	require XSLoader;
75	XSLoader::load IO::AIO, $VERSION;	77	XSLoader::load IO::AIO, $VERSION;
76	}	78	}
77		79
…		…
88	syscall has been executed asynchronously.	90	syscall has been executed asynchronously.
89		91
90	All functions expecting a filehandle keep a copy of the filehandle	92	All functions expecting a filehandle keep a copy of the filehandle
91	internally until the request has finished.	93	internally until the request has finished.
92		94
93	The filenames you pass to these routines I<must> be absolute. The reason	95	The pathnames you pass to these routines I<must> be absolute and
94	for this is that at the time the request is being executed, the current	96	encoded in byte form. The reason for the former is that at the time the
95	working directory could have changed. Alternatively, you can make sure	97	request is being executed, the current working directory could have
96	that you never change the current working directory.	98	changed. Alternatively, you can make sure that you never change the
		99	current working directory.
		100
		101	To encode pathnames to byte form, either make sure you either: a)
		102	always pass in filenames you got from outside (command line, readdir
		103	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
		104	your pathnames to the locale (or other) encoding in effect in the user
		105	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
		106	use something else.
97		107
98	=over 4	108	=over 4
99		109
100	=item aio_open $pathname, $flags, $mode, $callback	110	=item aio_open $pathname, $flags, $mode, $callback->($fh)
101		111
102	Asynchronously open or create a file and call the callback with a newly	112	Asynchronously open or create a file and call the callback with a newly
103	created filehandle for the file.	113	created filehandle for the file.
104		114
105	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	115	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
…		…
122	} else {	132	} else {
123	die "open failed: $!\n";	133	die "open failed: $!\n";
124	}	134	}
125	};	135	};
126		136
127	=item aio_close $fh, $callback	137	=item aio_close $fh, $callback->($status)
128		138
129	Asynchronously close a file and call the callback with the result	139	Asynchronously close a file and call the callback with the result
130	code. I<WARNING:> although accepted, you should not pass in a perl	140	code. I<WARNING:> although accepted, you should not pass in a perl
131	filehandle here, as perl will likely close the file descriptor another	141	filehandle here, as perl will likely close the file descriptor another
132	time when the filehandle is destroyed. Normally, you can safely call perls	142	time when the filehandle is destroyed. Normally, you can safely call perls
133	C<close> or just let filehandles go out of scope.	143	C<close> or just let filehandles go out of scope.
134		144
135	This is supposed to be a bug in the API, so that might change. It's	145	This is supposed to be a bug in the API, so that might change. It's
136	therefore best to avoid this function.	146	therefore best to avoid this function.
137		147
138	=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback	148	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
139		149
140	=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback	150	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
141		151
142	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	152	Reads or writes C<length> bytes from the specified C<fh> and C<offset>
143	into the scalar given by C<data> and offset C<dataoffset> and calls the	153	into the scalar given by C<data> and offset C<dataoffset> and calls the
144	callback without the actual number of bytes read (or -1 on error, just	154	callback without the actual number of bytes read (or -1 on error, just
145	like the syscall).	155	like the syscall).
146		156
		157	The C<$data> scalar I<MUST NOT> be modified in any way while the request
		158	is outstanding. Modifying it can result in segfaults or WW3 (if the
		159	necessary/optional hardware is installed).
		160
147	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	161	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
148	offset C<0> within the scalar:	162	offset C<0> within the scalar:
149		163
150	aio_read $fh, 7, 15, $buffer, 0, sub {	164	aio_read $fh, 7, 15, $buffer, 0, sub {
151	$_[0] > 0 or die "read error: $!";	165	$_[0] > 0 or die "read error: $!";
152	print "read $_[0] bytes: <$buffer>\n";	166	print "read $_[0] bytes: <$buffer>\n";
153	};	167	};
154		168
		169	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		170
		171	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
		172	reading at byte offset C<$in_offset>, and starts writing at the current
		173	file offset of C<$out_fh>. Because of that, it is not safe to issue more
		174	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
		175	other.
		176
		177	This call tries to make use of a native C<sendfile> syscall to provide
		178	zero-copy operation. For this to work, C<$out_fh> should refer to a
		179	socket, and C<$in_fh> should refer to mmap'able file.
		180
		181	If the native sendfile call fails or is not implemented, it will be
		182	emulated, so you can call C<aio_sendfile> on any type of filehandle
		183	regardless of the limitations of the operating system.
		184
		185	Please note, however, that C<aio_sendfile> can read more bytes from
		186	C<$in_fh> than are written, and there is no way to find out how many
		187	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
		188	provides the number of bytes written to C<$out_fh>. Only if the result
		189	value equals C<$length> one can assume that C<$length> bytes have been
		190	read.
		191
155	=item aio_readahead $fh,$offset,$length, $callback	192	=item aio_readahead $fh,$offset,$length, $callback->($retval)
156		193
157	C<aio_readahead> populates the page cache with data from a file so that	194	C<aio_readahead> populates the page cache with data from a file so that
158	subsequent reads from that file will not block on disk I/O. The C<$offset>	195	subsequent reads from that file will not block on disk I/O. The C<$offset>
159	argument specifies the starting point from which data is to be read and	196	argument specifies the starting point from which data is to be read and
160	C<$length> specifies the number of bytes to be read. I/O is performed in	197	C<$length> specifies the number of bytes to be read. I/O is performed in
…		…
164	file. The current file offset of the file is left unchanged.	201	file. The current file offset of the file is left unchanged.
165		202
166	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	203	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
167	emulated by simply reading the data, which would have a similar effect.	204	emulated by simply reading the data, which would have a similar effect.
168		205
169	=item aio_stat $fh_or_path, $callback	206	=item aio_stat $fh_or_path, $callback->($status)
170		207
171	=item aio_lstat $fh, $callback	208	=item aio_lstat $fh, $callback->($status)
172		209
173	Works like perl's C<stat> or C<lstat> in void context. The callback will	210	Works like perl's C<stat> or C<lstat> in void context. The callback will
174	be called after the stat and the results will be available using C<stat _>	211	be called after the stat and the results will be available using C<stat _>
175	or C<-s _> etc...	212	or C<-s _> etc...
176		213
…		…
186	aio_stat "/etc/passwd", sub {	223	aio_stat "/etc/passwd", sub {
187	$_[0] and die "stat failed: $!";	224	$_[0] and die "stat failed: $!";
188	print "size is ", -s _, "\n";	225	print "size is ", -s _, "\n";
189	};	226	};
190		227
191	=item aio_unlink $pathname, $callback	228	=item aio_unlink $pathname, $callback->($status)
192		229
193	Asynchronously unlink (delete) a file and call the callback with the	230	Asynchronously unlink (delete) a file and call the callback with the
194	result code.	231	result code.
195		232
		233	=item aio_rmdir $pathname, $callback->($status)
		234
		235	Asynchronously rmdir (delete) a directory and call the callback with the
		236	result code.
		237
		238	=item aio_readdir $pathname $callback->($entries)
		239
		240	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
		241	directory (i.e. opendir + readdir + closedir). The entries will not be
		242	sorted, and will B<NOT> include the C<.> and C<..> entries.
		243
		244	The callback a single argument which is either C<undef> or an array-ref
		245	with the filenames.
		246
		247	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		248
		249	Scans a directory (similar to C<aio_readdir>) and tries to separate the
		250	entries of directory C<$path> into two sets of names, ones you can recurse
		251	into (directories), and ones you cannot recurse into (everything else).
		252
		253	C<aio_scandir> is a composite request that consists of many
		254	aio-primitives. C<$maxreq> specifies the maximum number of outstanding
		255	aio requests that this function generates. If it is C<< <= 0 >>, then a
		256	suitable default will be chosen (currently 8).
		257
		258	On error, the callback is called without arguments, otherwise it receives
		259	two array-refs with path-relative entry names.
		260
		261	Example:
		262
		263	aio_scandir $dir, 0, sub {
		264	my ($dirs, $nondirs) = @_;
		265	print "real directories: @$dirs\n";
		266	print "everything else: @$nondirs\n";
		267	};
		268
		269	Implementation notes.
		270
		271	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
		272
		273	After reading the directory, the modification time, size etc. of the
		274	directory before and after the readdir is checked, and if they match, the
		275	link count will be used to decide how many entries are directories (if
		276	>= 2). Otherwise, no knowledge of the number of subdirectories will be
		277	assumed.
		278
		279	Then entires will be sorted into likely directories (everything without a
		280	non-initial dot) and likely non-directories (everything else). Then every
		281	entry + C</.> will be C<stat>'ed, likely directories first. This is often
		282	faster because filesystems might detect the type of the entry without
		283	reading the inode data (e.g. ext2s filetype feature). If that succeeds,
		284	it assumes that the entry is a directory or a symlink to directory (which
		285	will be checked seperately).
		286
		287	If the known number of directories has been reached, the rest of the
		288	entries is assumed to be non-directories.
		289
		290	=cut
		291
		292	sub aio_scandir($$$) {
		293	my ($path, $maxreq, $cb) = @_;
		294
		295	$maxreq = 8 if $maxreq <= 0;
		296
		297	# stat once
		298	aio_stat $path, sub {
		299	$cb->() if $_[0];
		300	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		301
		302	# read the directory entries
		303	aio_readdir $path, sub {
		304	my $entries = shift
		305	or return $cb->();
		306
		307	# stat the dir another time
		308	aio_stat $path, sub {
		309	my $hash2 = join ":", (stat _)[0,1,3,7,9];
		310
		311	my $ndirs;
		312
		313	# take the slow route if anything looks fishy
		314	if ($hash1 ne $hash2) {
		315	$ndirs = -1;
		316	} else {
		317	# if nlink == 2, we are finished
		318	# on non-posix-fs's, we rely on nlink < 2
		319	$ndirs = (stat _)[3] - 2
		320	or $cb->([], $entries);
		321	}
		322
		323	# sort into likely dirs and likely nondirs
		324	# dirs == files without ".", short entries first
		325	$entries = [map $_->[0],
		326	sort { $b->[1] cmp $a->[1] }
		327	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
		328	@$entries];
		329
		330	my (@dirs, @nondirs);
		331
		332	my ($statcb, $schedcb);
		333	my $nreq = 0;
		334
		335	$schedcb = sub {
		336	if (@$entries) {
		337	if ($nreq < $maxreq) {
		338	my $ent = pop @$entries;
		339	$nreq++;
		340	aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
		341	}
		342	} elsif (!$nreq) {
		343	# finished
		344	undef $statcb;
		345	undef $schedcb;
		346	$cb->(\@dirs, \@nondirs);
		347	undef $cb;
		348	}
		349	};
		350	$statcb = sub {
		351	my ($status, $entry) = @_;
		352
		353	if ($status < 0) {
		354	$nreq--;
		355	push @nondirs, $entry;
		356	&$schedcb;
		357	} else {
		358	# need to check for real directory
		359	aio_lstat "$path/$entry", sub {
		360	$nreq--;
		361
		362	if (-d _) {
		363	push @dirs, $entry;
		364
		365	if (!--$ndirs) {
		366	push @nondirs, @$entries;
		367	$entries = [];
		368	}
		369	} else {
		370	push @nondirs, $entry;
		371	}
		372
		373	&$schedcb;
		374	}
		375	}
		376	};
		377
		378	&$schedcb while @$entries && $nreq < $maxreq;
		379	};
		380	};
		381	};
		382	}
		383
196	=item aio_fsync $fh, $callback	384	=item aio_fsync $fh, $callback->($status)
197		385
198	Asynchronously call fsync on the given filehandle and call the callback	386	Asynchronously call fsync on the given filehandle and call the callback
199	with the fsync result code.	387	with the fsync result code.
200		388
201	=item aio_fdatasync $fh, $callback	389	=item aio_fdatasync $fh, $callback->($status)
202		390
203	Asynchronously call fdatasync on the given filehandle and call the	391	Asynchronously call fdatasync on the given filehandle and call the
204	callback with the fdatasync result code.	392	callback with the fdatasync result code.
205		393
206	If this call isn't available because your OS lacks it or it couldn't be	394	If this call isn't available because your OS lacks it or it couldn't be
…		…
270	IO::AIO::poll_wait, IO::AIO::poll_cb	458	IO::AIO::poll_wait, IO::AIO::poll_cb
271	if IO::AIO::nreqs;	459	if IO::AIO::nreqs;
272		460
273	=item IO::AIO::min_parallel $nthreads	461	=item IO::AIO::min_parallel $nthreads
274		462
275	Set the minimum number of AIO threads to C<$nthreads>. The default is	463	Set the minimum number of AIO threads to C<$nthreads>. The current default
276	C<1>, which means a single asynchronous operation can be done at one time	464	is C<4>, which means four asynchronous operations can be done at one time
277	(the number of outstanding operations, however, is unlimited).	465	(the number of outstanding operations, however, is unlimited).
		466
		467	IO::AIO starts threads only on demand, when an AIO request is queued and
		468	no free thread exists.
278		469
279	It is recommended to keep the number of threads low, as some Linux	470	It is recommended to keep the number of threads low, as some Linux
280	kernel versions will scale negatively with the number of threads (higher	471	kernel versions will scale negatively with the number of threads (higher
281	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	472	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
282	threads should be fine.	473	threads should be fine.
283		474
284	Under normal circumstances you don't need to call this function, as this	475	Under most circumstances you don't need to call this function, as the
285	module automatically starts some threads (the exact number might change,	476	module selects a default that is suitable for low to moderate load.
286	and is currently 4).
287		477
288	=item IO::AIO::max_parallel $nthreads	478	=item IO::AIO::max_parallel $nthreads
289		479
290	Sets the maximum number of AIO threads to C<$nthreads>. If more than	480	Sets the maximum number of AIO threads to C<$nthreads>. If more than the
291	the specified number of threads are currently running, kill them. This	481	specified number of threads are currently running, this function kills
292	function blocks until the limit is reached.	482	them. This function blocks until the limit is reached.
		483
		484	While C<$nthreads> are zero, aio requests get queued but not executed
		485	until the number of threads has been increased again.
293		486
294	This module automatically runs C<max_parallel 0> at program end, to ensure	487	This module automatically runs C<max_parallel 0> at program end, to ensure
295	that all threads are killed and that there are no outstanding requests.	488	that all threads are killed and that there are no outstanding requests.
296		489
297	Under normal circumstances you don't need to call this function.	490	Under normal circumstances you don't need to call this function.
…		…
301	Sets the maximum number of outstanding requests to C<$nreqs>. If you	494	Sets the maximum number of outstanding requests to C<$nreqs>. If you
302	try to queue up more than this number of requests, the caller will block until	495	try to queue up more than this number of requests, the caller will block until
303	some requests have been handled.	496	some requests have been handled.
304		497
305	The default is very large, so normally there is no practical limit. If you	498	The default is very large, so normally there is no practical limit. If you
306	queue up many requests in a loop it it often improves speed if you set	499	queue up many requests in a loop it often improves speed if you set
307	this to a relatively low number, such as C<100>.	500	this to a relatively low number, such as C<100>.
308		501
309	Under normal circumstances you don't need to call this function.	502	Under normal circumstances you don't need to call this function.
310		503
311	=back	504	=back
…		…
318		511
319	# try to generate nice filehandles	512	# try to generate nice filehandles
320	my $sym = "IO::AIO::fd#$_[0]";	513	my $sym = "IO::AIO::fd#$_[0]";
321	local *$sym;	514	local *$sym;
322		515
323	open *$sym, "+<&$_[0]" # usually under any unix	516	open *$sym, "+<&=$_[0]" # usually works under any unix
324	or open *$sym, "<&$_[0]" # cygwin needs this	517	or open *$sym, "<&=$_[0]" # cygwin needs this
325	or open *$sym, ">&$_[0]" # cygwin needs this	518	or open *$sym, ">&=$_[0]" # or this
326	or return undef;	519	or return undef;
327		520
328	*$sym	521	*$sym
329	}	522	}
330		523
…		…
334	max_parallel 0;	527	max_parallel 0;
335	}	528	}
336		529
337	1;	530	1;
338		531
		532	=head2 FORK BEHAVIOUR
		533
		534	Before the fork, IO::AIO enters a quiescent state where no requests
		535	can be added in other threads and no results will be processed. After
		536	the fork the parent simply leaves the quiescent state and continues
		537	request/result processing, while the child clears the request/result
		538	queue (so the requests started before the fork will only be handled in
		539	the parent). Threats will be started on demand until the limit ste in the
		540	parent process has been reached again.
		541
339	=head1 SEE ALSO	542	=head1 SEE ALSO
340		543
341	L<Coro>, L<Linux::AIO>.	544	L<Coro>, L<Linux::AIO>.
342		545
343	=head1 AUTHOR	546	=head1 AUTHOR

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.26 by root, Sun Aug 7 03:34:07 2005 UTC vs. Revision 1.40 by root, Tue Aug 30 15:45:10 2005 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.26 by root, Sun Aug 7 03:34:07 2005 UTC vs.
Revision 1.40 by root, Tue Aug 30 15:45:10 2005 UTC