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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.21 by root, Wed Jul 13 00:13:09 2005 UTC vs.
Revision 1.39 by root, Sun Aug 28 11:05:50 2005 UTC

…		…
22	poll => 'r',	22	poll => 'r',
23	cb => \&IO::AIO::poll_cb);	23	cb => \&IO::AIO::poll_cb);
24		24
25	# Glib/Gtk2	25	# Glib/Gtk2
26	add_watch Glib::IO IO::AIO::poll_fileno,	26	add_watch Glib::IO IO::AIO::poll_fileno,
27	in => sub { IO::AIO::poll_cb, 1 };	27	in => sub { IO::AIO::poll_cb; 1 };
28		28
29	# Tk	29	# Tk
30	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",	30	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
31	readable => \&IO::AIO::poll_cb);	31	readable => \&IO::AIO::poll_cb);
32		32
…		…
48	not well-supported (Linux doesn't allow them on normal files currently,	48	not well-supported (Linux doesn't allow them on normal files currently,
49	for example), and they would only support aio_read and aio_write, so the	49	for example), and they would only support aio_read and aio_write, so the
50	remaining functionality would have to be implemented using threads anyway.	50	remaining functionality would have to be implemented using threads anyway.
51		51
52	Although the module will work with in the presence of other threads, it is	52	Although the module will work with in the presence of other threads, it is
53	currently not reentrant, so use appropriate locking yourself.	53	currently not reentrant, so use appropriate locking yourself, always call
		54	C<poll_cb> from within the same thread, or never call C<poll_cb> (or other
		55	C<aio_> functions) recursively.
54		56
55	=cut	57	=cut
56		58
57	package IO::AIO;	59	package IO::AIO;
58		60
		61	no warnings;
		62
59	use base 'Exporter';	63	use base 'Exporter';
60		64
61	use Fcntl ();	65	use Fcntl ();
62		66
63	BEGIN {	67	BEGIN {
64	$VERSION = 0.9;	68	$VERSION = 1.6;
65		69
66	@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_symlink
67	aio_fsync aio_fdatasync aio_readahead);	72	aio_fsync aio_fdatasync aio_readahead);
68	@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);
69		75
70	require XSLoader;	76	require XSLoader;
71	XSLoader::load IO::AIO, $VERSION;	77	XSLoader::load IO::AIO, $VERSION;
72	}	78	}
73		79
…		…
81	which must be a code reference. This code reference will get called with	87	which must be a code reference. This code reference will get called with
82	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	88	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
83	perl, which usually delivers "false") as it's sole argument when the given	89	perl, which usually delivers "false") as it's sole argument when the given
84	syscall has been executed asynchronously.	90	syscall has been executed asynchronously.
85		91
86	All functions that expect a filehandle will also accept a file descriptor.	92	All functions expecting a filehandle keep a copy of the filehandle
		93	internally until the request has finished.
87		94
88	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
89	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
90	working directory could have changed. Alternatively, you can make sure	97	request is being executed, the current working directory could have
91	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.
92		107
93	=over 4	108	=over 4
94		109
95	=item aio_open $pathname, $flags, $mode, $callback	110	=item aio_open $pathname, $flags, $mode, $callback
96		111
…		…
137	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	152	Reads or writes C<length> bytes from the specified C<fh> and C<offset>
138	into the scalar given by C<data> and offset C<dataoffset> and calls the	153	into the scalar given by C<data> and offset C<dataoffset> and calls the
139	callback without the actual number of bytes read (or -1 on error, just	154	callback without the actual number of bytes read (or -1 on error, just
140	like the syscall).	155	like the syscall).
141		156
		157	The C<$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
142	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
143	offset C<0> within the scalar:	162	offset C<0> within the scalar:
144		163
145	aio_read $fh, 7, 15, $buffer, 0, sub {	164	aio_read $fh, 7, 15, $buffer, 0, sub {
146	$_[0] > 0 or die "read error: $!";	165	$_[0] > 0 or die "read error: $!";
147	print "read $_[0] bytes: <$buffer>\n";	166	print "read $_[0] bytes: <$buffer>\n";
148	};	167	};
149		168
		169	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback
		170
		171	Tries to copy C<$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
150	=item aio_readahead $fh,$offset,$length, $callback	192	=item aio_readahead $fh,$offset,$length, $callback
151
152	Asynchronously reads the specified byte range into the page cache, using
153	the C<readahead> syscall. If that syscall doesn't exist (likely if your OS
154	isn't Linux) the status will be C<-1> and C<$!> is set to C<ENOSYS>.
155		193
156	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
157	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>
158	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
159	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
160	whole pages, so that offset is effectively rounded down to a page boundary	198	whole pages, so that offset is effectively rounded down to a page boundary
161	and bytes are read up to the next page boundary greater than or equal to	199	and bytes are read up to the next page boundary greater than or equal to
162	(off-set+length). C<aio_readahead> does not read beyond the end of the	200	(off-set+length). C<aio_readahead> does not read beyond the end of the
163	file. The current file offset of the file is left unchanged.	201	file. The current file offset of the file is left unchanged.
164		202
		203	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
		204	emulated by simply reading the data, which would have a similar effect.
		205
165	=item aio_stat $fh_or_path, $callback	206	=item aio_stat $fh_or_path, $callback
166		207
167	=item aio_lstat $fh, $callback	208	=item aio_lstat $fh, $callback
168		209
169	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
…		…
187	=item aio_unlink $pathname, $callback	228	=item aio_unlink $pathname, $callback
188		229
189	Asynchronously unlink (delete) a file and call the callback with the	230	Asynchronously unlink (delete) a file and call the callback with the
190	result code.	231	result code.
191		232
		233	=item aio_rmdir $pathname, $callback
		234
		235	Asynchronously rmdir (delete) a directory and call the callback with the
		236	result code.
		237
		238	=item aio_readdir $pathname $callback
		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
192	=item aio_fsync $fh, $callback	247	=item aio_fsync $fh, $callback
193		248
194	Asynchronously call fsync on the given filehandle and call the callback	249	Asynchronously call fsync on the given filehandle and call the callback
195	with the fsync result code.	250	with the fsync result code.
196		251
197	=item aio_fdatasync $fh, $callback	252	=item aio_fdatasync $fh, $callback
198		253
199	Asynchronously call fdatasync on the given filehandle and call the	254	Asynchronously call fdatasync on the given filehandle and call the
200	callback with the fdatasync result code. Might set C<$!> to C<ENOSYS> if	255	callback with the fdatasync result code.
201	C<fdatasync> is not available.	256
		257	If this call isn't available because your OS lacks it or it couldn't be
		258	detected, it will be emulated by calling C<fsync> instead.
202		259
203	=back	260	=back
204		261
205	=head2 SUPPORT FUNCTIONS	262	=head2 SUPPORT FUNCTIONS
206		263
…		…
264	IO::AIO::poll_wait, IO::AIO::poll_cb	321	IO::AIO::poll_wait, IO::AIO::poll_cb
265	if IO::AIO::nreqs;	322	if IO::AIO::nreqs;
266		323
267	=item IO::AIO::min_parallel $nthreads	324	=item IO::AIO::min_parallel $nthreads
268		325
269	Set the minimum number of AIO threads to C<$nthreads>. The default is	326	Set the minimum number of AIO threads to C<$nthreads>. The current default
270	C<1>, which means a single asynchronous operation can be done at one time	327	is C<4>, which means four asynchronous operations can be done at one time
271	(the number of outstanding operations, however, is unlimited).	328	(the number of outstanding operations, however, is unlimited).
		329
		330	IO::AIO starts threads only on demand, when an AIO request is queued and
		331	no free thread exists.
272		332
273	It is recommended to keep the number of threads low, as some Linux	333	It is recommended to keep the number of threads low, as some Linux
274	kernel versions will scale negatively with the number of threads (higher	334	kernel versions will scale negatively with the number of threads (higher
275	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	335	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
276	threads should be fine.	336	threads should be fine.
277		337
278	Under normal circumstances you don't need to call this function, as this	338	Under most circumstances you don't need to call this function, as the
279	module automatically starts some threads (the exact number might change,	339	module selects a default that is suitable for low to moderate load.
280	and is currently 4).
281		340
282	=item IO::AIO::max_parallel $nthreads	341	=item IO::AIO::max_parallel $nthreads
283		342
284	Sets the maximum number of AIO threads to C<$nthreads>. If more than	343	Sets the maximum number of AIO threads to C<$nthreads>. If more than the
285	the specified number of threads are currently running, kill them. This	344	specified number of threads are currently running, this function kills
286	function blocks until the limit is reached.	345	them. This function blocks until the limit is reached.
		346
		347	While C<$nthreads> are zero, aio requests get queued but not executed
		348	until the number of threads has been increased again.
287		349
288	This module automatically runs C<max_parallel 0> at program end, to ensure	350	This module automatically runs C<max_parallel 0> at program end, to ensure
289	that all threads are killed and that there are no outstanding requests.	351	that all threads are killed and that there are no outstanding requests.
290		352
291	Under normal circumstances you don't need to call this function.	353	Under normal circumstances you don't need to call this function.
…		…
295	Sets the maximum number of outstanding requests to C<$nreqs>. If you	357	Sets the maximum number of outstanding requests to C<$nreqs>. If you
296	try to queue up more than this number of requests, the caller will block until	358	try to queue up more than this number of requests, the caller will block until
297	some requests have been handled.	359	some requests have been handled.
298		360
299	The default is very large, so normally there is no practical limit. If you	361	The default is very large, so normally there is no practical limit. If you
300	queue up many requests in a loop it it often improves speed if you set	362	queue up many requests in a loop it often improves speed if you set
301	this to a relatively low number, such as C<100>.	363	this to a relatively low number, such as C<100>.
302		364
303	Under normal circumstances you don't need to call this function.	365	Under normal circumstances you don't need to call this function.
304		366
305	=back	367	=back
…		…
308		370
309	# support function to convert a fd into a perl filehandle	371	# support function to convert a fd into a perl filehandle
310	sub _fd2fh {	372	sub _fd2fh {
311	return undef if $_[0] < 0;	373	return undef if $_[0] < 0;
312		374
313	# try to be perl5.6-compatible	375	# try to generate nice filehandles
314	local *AIO_FH;	376	my $sym = "IO::AIO::fd#$_[0]";
315	open AIO_FH, "+<&=$_[0]"	377	local *$sym;
		378
		379	open *$sym, "+<&=$_[0]" # usually works under any unix
		380	or open *$sym, "<&=$_[0]" # cygwin needs this
		381	or open *$sym, ">&=$_[0]" # or this
316	or return undef;	382	or return undef;
317		383
318	*AIO_FH	384	*$sym
319	}	385	}
320		386
321	min_parallel 4;	387	min_parallel 4;
322		388
323	END {	389	END {
324	max_parallel 0;	390	max_parallel 0;
325	}	391	}
326		392
327	1;	393	1;
328		394
		395	=head2 FORK BEHAVIOUR
		396
		397	Before the fork, IO::AIO enters a quiescent state where no requests
		398	can be added in other threads and no results will be processed. After
		399	the fork the parent simply leaves the quiescent state and continues
		400	request/result processing, while the child clears the request/result
		401	queue (so the requests started before the fork will only be handled in
		402	the parent). Threats will be started on demand until the limit ste in the
		403	parent process has been reached again.
		404
329	=head1 SEE ALSO	405	=head1 SEE ALSO
330		406
331	L<Coro>, L<Linux::AIO>.	407	L<Coro>, L<Linux::AIO>.
332		408
333	=head1 AUTHOR	409	=head1 AUTHOR

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.21 by root, Wed Jul 13 00:13:09 2005 UTC vs. Revision 1.39 by root, Sun Aug 28 11:05:50 2005 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.21 by root, Wed Jul 13 00:13:09 2005 UTC vs.
Revision 1.39 by root, Sun Aug 28 11:05:50 2005 UTC