[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 1.36 by root, Tue Aug 23 00:03:14 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_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
67	aio_fsync aio_fdatasync aio_readahead);	71	aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead);
68	@EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	72	@EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
69		73
70	require XSLoader;	74	require XSLoader;
71	XSLoader::load IO::AIO, $VERSION;	75	XSLoader::load IO::AIO, $VERSION;
72	}	76	}
…		…
81	which must be a code reference. This code reference will get called with	85	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	86	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	87	perl, which usually delivers "false") as it's sole argument when the given
84	syscall has been executed asynchronously.	88	syscall has been executed asynchronously.
85		89
86	All functions that expect a filehandle will also accept a file descriptor.	90	All functions expecting a filehandle keep a copy of the filehandle
		91	internally until the request has finished.
87		92
88	The filenames you pass to these routines I<must> be absolute. The reason	93	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	94	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	95	request is being executed, the current working directory could have
91	that you never change the current working directory.	96	changed. Alternatively, you can make sure that you never change the
		97	current working directory.
		98
		99	To encode pathnames to byte form, either make sure you either: a)
		100	always pass in filenames you got from outside (command line, readdir
		101	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
		102	your pathnames to the locale (or other) encoding in effect in the user
		103	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
		104	use something else.
92		105
93	=over 4	106	=over 4
94		107
95	=item aio_open $pathname, $flags, $mode, $callback	108	=item aio_open $pathname, $flags, $mode, $callback
96		109
…		…
137	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	150	Reads or writes C<length> bytes from the specified C<fh> and C<offset>
138	into the scalar given by C<data> and offset C<dataoffset> and calls the	151	into the scalar given by C<data> and offset C<dataoffset> and calls the
139	callback without the actual number of bytes read (or -1 on error, just	152	callback without the actual number of bytes read (or -1 on error, just
140	like the syscall).	153	like the syscall).
141		154
		155	The C<$data> scalar I<MUST NOT> be modified in any way while the request
		156	is outstanding. Modifying it can result in segfaults or WW3 (if the
		157	necessary/optional hardware is installed).
		158
142	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	159	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
143	offset C<0> within the scalar:	160	offset C<0> within the scalar:
144		161
145	aio_read $fh, 7, 15, $buffer, 0, sub {	162	aio_read $fh, 7, 15, $buffer, 0, sub {
146	$_[0] > 0 or die "read error: $!";	163	$_[0] > 0 or die "read error: $!";
147	print "read $_[0] bytes: <$buffer>\n";	164	print "read $_[0] bytes: <$buffer>\n";
148	};	165	};
149		166
		167	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback
		168
		169	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
		170	reading at byte offset C<$in_offset>, and starts writing at the current
		171	file offset of C<$out_fh>. Because of that, it is not safe to issue more
		172	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
		173	other.
		174
		175	This call tries to make use of a native C<sendfile> syscall to provide
		176	zero-copy operation. For this to work, C<$out_fh> should refer to a
		177	socket, and C<$in_fh> should refer to mmap'able file.
		178
		179	If the native sendfile call fails or is not implemented, it will be
		180	emulated, so you can call C<aio_sendfile> on any type of filehandle
		181	regardless of the limitations of the operating system.
		182
		183	Please note, however, that C<aio_sendfile> can read more bytes from
		184	C<$in_fh> than are written, and there is no way to find out how many
		185	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
		186	provides the number of bytes written to C<$out_fh>. Only if the result
		187	value equals C<$length> one can assume that C<$length> bytes have been
		188	read.
		189
150	=item aio_readahead $fh,$offset,$length, $callback	190	=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		191
156	C<aio_readahead> populates the page cache with data from a file so that	192	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<$offset>	193	subsequent reads from that file will not block on disk I/O. The C<$offset>
158	argument specifies the starting point from which data is to be read and	194	argument specifies the starting point from which data is to be read and
159	C<$length> specifies the number of bytes to be read. I/O is performed in	195	C<$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	196	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	197	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	198	(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.	199	file. The current file offset of the file is left unchanged.
164		200
		201	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
		202	emulated by simply reading the data, which would have a similar effect.
		203
165	=item aio_stat $fh_or_path, $callback	204	=item aio_stat $fh_or_path, $callback
166		205
167	=item aio_lstat $fh, $callback	206	=item aio_lstat $fh, $callback
168		207
169	Works like perl's C<stat> or C<lstat> in void context. The callback will	208	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
187	=item aio_unlink $pathname, $callback	226	=item aio_unlink $pathname, $callback
188		227
189	Asynchronously unlink (delete) a file and call the callback with the	228	Asynchronously unlink (delete) a file and call the callback with the
190	result code.	229	result code.
191		230
		231	=item aio_rmdir $pathname, $callback
		232
		233	Asynchronously rmdir (delete) a directory and call the callback with the
		234	result code.
		235
192	=item aio_fsync $fh, $callback	236	=item aio_fsync $fh, $callback
193		237
194	Asynchronously call fsync on the given filehandle and call the callback	238	Asynchronously call fsync on the given filehandle and call the callback
195	with the fsync result code.	239	with the fsync result code.
196		240
197	=item aio_fdatasync $fh, $callback	241	=item aio_fdatasync $fh, $callback
198		242
199	Asynchronously call fdatasync on the given filehandle and call the	243	Asynchronously call fdatasync on the given filehandle and call the
200	callback with the fdatasync result code. Might set C<$!> to C<ENOSYS> if	244	callback with the fdatasync result code.
201	C<fdatasync> is not available.	245
		246	If this call isn't available because your OS lacks it or it couldn't be
		247	detected, it will be emulated by calling C<fsync> instead.
202		248
203	=back	249	=back
204		250
205	=head2 SUPPORT FUNCTIONS	251	=head2 SUPPORT FUNCTIONS
206		252
…		…
264	IO::AIO::poll_wait, IO::AIO::poll_cb	310	IO::AIO::poll_wait, IO::AIO::poll_cb
265	if IO::AIO::nreqs;	311	if IO::AIO::nreqs;
266		312
267	=item IO::AIO::min_parallel $nthreads	313	=item IO::AIO::min_parallel $nthreads
268		314
269	Set the minimum number of AIO threads to C<$nthreads>. The default is	315	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	316	is C<4>, which means four asynchronous operations can be done at one time
271	(the number of outstanding operations, however, is unlimited).	317	(the number of outstanding operations, however, is unlimited).
		318
		319	IO::AIO starts threads only on demand, when an AIO request is queued and
		320	no free thread exists.
272		321
273	It is recommended to keep the number of threads low, as some Linux	322	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	323	kernel versions will scale negatively with the number of threads (higher
275	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	324	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32
276	threads should be fine.	325	threads should be fine.
277		326
278	Under normal circumstances you don't need to call this function, as this	327	Under most circumstances you don't need to call this function, as the
279	module automatically starts some threads (the exact number might change,	328	module selects a default that is suitable for low to moderate load.
280	and is currently 4).
281		329
282	=item IO::AIO::max_parallel $nthreads	330	=item IO::AIO::max_parallel $nthreads
283		331
284	Sets the maximum number of AIO threads to C<$nthreads>. If more than	332	Sets the maximum number of AIO threads to C<$nthreads>. If more than the
285	the specified number of threads are currently running, kill them. This	333	specified number of threads are currently running, this function kills
286	function blocks until the limit is reached.	334	them. This function blocks until the limit is reached.
		335
		336	While C<$nthreads> are zero, aio requests get queued but not executed
		337	until the number of threads has been increased again.
287		338
288	This module automatically runs C<max_parallel 0> at program end, to ensure	339	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.	340	that all threads are killed and that there are no outstanding requests.
290		341
291	Under normal circumstances you don't need to call this function.	342	Under normal circumstances you don't need to call this function.
…		…
295	Sets the maximum number of outstanding requests to C<$nreqs>. If you	346	Sets the maximum number of outstanding requests to C<$nreqs>. If you
296	try to queue up more than this number of requests, the caller will block until	347	try to queue up more than this number of requests, the caller will block until
297	some requests have been handled.	348	some requests have been handled.
298		349
299	The default is very large, so normally there is no practical limit. If you	350	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	351	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>.	352	this to a relatively low number, such as C<100>.
302		353
303	Under normal circumstances you don't need to call this function.	354	Under normal circumstances you don't need to call this function.
304		355
305	=back	356	=back
…		…
308		359
309	# support function to convert a fd into a perl filehandle	360	# support function to convert a fd into a perl filehandle
310	sub _fd2fh {	361	sub _fd2fh {
311	return undef if $_[0] < 0;	362	return undef if $_[0] < 0;
312		363
313	# try to be perl5.6-compatible	364	# try to generate nice filehandles
314	local *AIO_FH;	365	my $sym = "IO::AIO::fd#$_[0]";
315	open AIO_FH, "+<&=$_[0]"	366	local *$sym;
		367
		368	open *$sym, "+<&=$_[0]" # usually works under any unix
		369	or open *$sym, "<&=$_[0]" # cygwin needs this
		370	or open *$sym, ">&=$_[0]" # or this
316	or return undef;	371	or return undef;
317		372
318	*AIO_FH	373	*$sym
319	}	374	}
320		375
321	min_parallel 4;	376	min_parallel 4;
322		377
323	END {	378	END {
324	max_parallel 0;	379	max_parallel 0;
325	}	380	}
326		381
327	1;	382	1;
328		383
		384	=head2 FORK BEHAVIOUR
		385
		386	Before the fork, IO::AIO enters a quiescent state where no requests
		387	can be added in other threads and no results will be processed. After
		388	the fork the parent simply leaves the quiescent state and continues
		389	request/result processing, while the child clears the request/result
		390	queue (so the requests started before the fork will only be handled in
		391	the parent). Threats will be started on demand until the limit ste in the
		392	parent process has been reached again.
		393
329	=head1 SEE ALSO	394	=head1 SEE ALSO
330		395
331	L<Coro>, L<Linux::AIO>.	396	L<Coro>, L<Linux::AIO>.
332		397
333	=head1 AUTHOR	398	=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 1.36 by root, Tue Aug 23 00:03:14 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 1.36 by root, Tue Aug 23 00:03:14 2005 UTC