[ViewVC] Diff of: cvs/IO-AIO/README

Comparing IO-AIO/README (file contents):
Revision 1.41 by root, Sat Jan 2 14:24:32 2010 UTC vs.
Revision 1.47 by root, Fri May 27 00:44:49 2011 UTC

…		…
2	IO::AIO - Asynchronous Input/Output	2	IO::AIO - Asynchronous Input/Output
3		3
4	SYNOPSIS	4	SYNOPSIS
5	use IO::AIO;	5	use IO::AIO;
6		6
7	aio_open "/etc/passwd", O_RDONLY, 0, sub {	7	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
8	my $fh = shift	8	my $fh = shift
9	or die "/etc/passwd: $!";	9	or die "/etc/passwd: $!";
10	...	10	...
11	};	11	};
12		12
…		…
23	my $req = aio_unlink "/tmp/file", sub { };	23	my $req = aio_unlink "/tmp/file", sub { };
24	$req->cancel; # cancel request if still in queue	24	$req->cancel; # cancel request if still in queue
25		25
26	my $grp = aio_group sub { print "all stats done\n" };	26	my $grp = aio_group sub { print "all stats done\n" };
27	add $grp aio_stat "..." for ...;	27	add $grp aio_stat "..." for ...;
28
29	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
30	use AnyEvent::AIO;
31
32	# EV integration
33	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51		28
52	DESCRIPTION	29	DESCRIPTION
53	This module implements asynchronous I/O using whatever means your	30	This module implements asynchronous I/O using whatever means your
54	operating system supports. It is implemented as an interface to "libeio"	31	operating system supports. It is implemented as an interface to "libeio"
55	(<http://software.schmorp.de/pkg/libeio.html>).	32	(<http://software.schmorp.de/pkg/libeio.html>).
…		…
95		72
96	# register the IO::AIO callback with EV	73	# register the IO::AIO callback with EV
97	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	74	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98		75
99	# queue the request to open /etc/passwd	76	# queue the request to open /etc/passwd
100	aio_open "/etc/passwd", O_RDONLY, 0, sub {	77	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
101	my $fh = shift	78	my $fh = shift
102	or die "error while opening: $!";	79	or die "error while opening: $!";
103		80
104	# stat'ing filehandles is generally non-blocking	81	# stat'ing filehandles is generally non-blocking
105	my $size = -s $fh;	82	my $size = -s $fh;
…		…
168	anymore (except possibly for the Perl object, but its connection to	145	anymore (except possibly for the Perl object, but its connection to
169	the actual aio request is severed and calling its methods will	146	the actual aio request is severed and calling its methods will
170	either do nothing or result in a runtime error).	147	either do nothing or result in a runtime error).
171		148
172	FUNCTIONS	149	FUNCTIONS
		150	QUICK OVERVIEW
		151	This section simply lists the prototypes of the most important functions
		152	for quick reference. See the following sections for function-by-function
		153	documentation.
		154
		155	aio_open $pathname, $flags, $mode, $callback->($fh)
		156	aio_close $fh, $callback->($status)
		157	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		158	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		159	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		160	aio_readahead $fh,$offset,$length, $callback->($retval)
		161	aio_stat $fh_or_path, $callback->($status)
		162	aio_lstat $fh, $callback->($status)
		163	aio_statvfs $fh_or_path, $callback->($statvfs)
		164	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		165	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		166	aio_truncate $fh_or_path, $offset, $callback->($status)
		167	aio_chmod $fh_or_path, $mode, $callback->($status)
		168	aio_unlink $pathname, $callback->($status)
		169	aio_mknod $path, $mode, $dev, $callback->($status)
		170	aio_link $srcpath, $dstpath, $callback->($status)
		171	aio_symlink $srcpath, $dstpath, $callback->($status)
		172	aio_readlink $path, $callback->($link)
		173	aio_rename $srcpath, $dstpath, $callback->($status)
		174	aio_mkdir $pathname, $mode, $callback->($status)
		175	aio_rmdir $pathname, $callback->($status)
		176	aio_readdir $pathname, $callback->($entries)
		177	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		178	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		179	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		180	aio_load $path, $data, $callback->($status)
		181	aio_copy $srcpath, $dstpath, $callback->($status)
		182	aio_move $srcpath, $dstpath, $callback->($status)
		183	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		184	aio_rmtree $path, $callback->($status)
		185	aio_sync $callback->($status)
		186	aio_fsync $fh, $callback->($status)
		187	aio_fdatasync $fh, $callback->($status)
		188	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		189	aio_pathsync $path, $callback->($status)
		190	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		191	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		192	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		193	aio_mlockall $flags, $callback->($status)
		194	aio_group $callback->(...)
		195	aio_nop $callback->()
		196
		197	$prev_pri = aioreq_pri [$pri]
		198	aioreq_nice $pri_adjust
		199
		200	IO::AIO::poll_wait
		201	IO::AIO::poll_cb
		202	IO::AIO::poll
		203	IO::AIO::flush
		204	IO::AIO::max_poll_reqs $nreqs
		205	IO::AIO::max_poll_time $seconds
		206	IO::AIO::min_parallel $nthreads
		207	IO::AIO::max_parallel $nthreads
		208	IO::AIO::max_idle $nthreads
		209	IO::AIO::idle_timeout $seconds
		210	IO::AIO::max_outstanding $maxreqs
		211	IO::AIO::nreqs
		212	IO::AIO::nready
		213	IO::AIO::npending
		214
		215	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		216	IO::AIO::fadvise $fh, $offset, $len, $advice
		217	IO::AIO::madvise $scalar, $offset, $length, $advice
		218	IO::AIO::mprotect $scalar, $offset, $length, $protect
		219	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		220	IO::AIO::munlockall
		221
173	AIO REQUEST FUNCTIONS	222	AIO REQUEST FUNCTIONS
174	All the "aio_*" calls are more or less thin wrappers around the syscall	223	All the "aio_*" calls are more or less thin wrappers around the syscall
175	with the same name (sans "aio_"). The arguments are similar or	224	with the same name (sans "aio_"). The arguments are similar or
176	identical, and they all accept an additional (and optional) $callback	225	identical, and they all accept an additional (and optional) $callback
177	argument which must be a code reference. This code reference will get	226	argument which must be a code reference. This code reference will get
…		…
248	will be modified by the umask in effect then the request is being	297	will be modified by the umask in effect then the request is being
249	executed, so better never change the umask.	298	executed, so better never change the umask.
250		299
251	Example:	300	Example:
252		301
253	aio_open "/etc/passwd", O_RDONLY, 0, sub {	302	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
254	if ($_[0]) {	303	if ($_[0]) {
255	print "open successful, fh is $_[0]\n";	304	print "open successful, fh is $_[0]\n";
256	...	305	...
257	} else {	306	} else {
258	die "open failed: $!\n";	307	die "open failed: $!\n";
259	}	308	}
260	};	309	};
261		310
		311	In addition to all the common open modes/flags ("O_RDONLY",
		312	"O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and
		313	"O_APPEND"), the following POSIX and non-POSIX constants are
		314	available (missing ones on your system are, as usual, 0):
		315
		316	"O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
		317	"O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
		318	"O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT".
		319
262	aio_close $fh, $callback->($status)	320	aio_close $fh, $callback->($status)
263	Asynchronously close a file and call the callback with the result	321	Asynchronously close a file and call the callback with the result
264	code.	322	code.
265		323
266	Unfortunately, you can't do this to perl. Perl insists very	324	Unfortunately, you can't do this to perl. Perl insists very
…		…
311	reading at byte offset $in_offset, and starts writing at the current	369	reading at byte offset $in_offset, and starts writing at the current
312	file offset of $out_fh. Because of that, it is not safe to issue	370	file offset of $out_fh. Because of that, it is not safe to issue
313	more than one "aio_sendfile" per $out_fh, as they will interfere	371	more than one "aio_sendfile" per $out_fh, as they will interfere
314	with each other.	372	with each other.
315		373
		374	Please note that "aio_sendfile" can read more bytes from $in_fh than
		375	are written, and there is no way to find out how many bytes have
		376	been read from "aio_sendfile" alone, as "aio_sendfile" only provides
		377	the number of bytes written to $out_fh. Only if the result value
		378	equals $length one can assume that $length bytes have been read.
		379
		380	Unlike with other "aio_" functions, it makes a lot of sense to use
		381	"aio_sendfile" on non-blocking sockets, as long as one end
		382	(typically the $in_fh) is a file - the file I/O will then be
		383	asynchronous, while the socket I/O will be non-blocking. Note,
		384	however, that you can run into a trap where "aio_sendfile" reads
		385	some data with readahead, then fails to write all data, and when the
		386	socket is ready the next time, the data in the cache is already
		387	lost, forcing "aio_sendfile" to again hit the disk. Explicit
		388	"aio_read" + "aio_write" let's you control resource usage much
		389	better.
		390
316	This call tries to make use of a native "sendfile" syscall to	391	This call tries to make use of a native "sendfile" syscall to
317	provide zero-copy operation. For this to work, $out_fh should refer	392	provide zero-copy operation. For this to work, $out_fh should refer
318	to a socket, and $in_fh should refer to mmap'able file.	393	to a socket, and $in_fh should refer to an mmap'able file.
319		394
320	If a native sendfile cannot be found or it fails with "ENOSYS",	395	If a native sendfile cannot be found or it fails with "ENOSYS",
321	"ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK",	396	"ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK",
322	it will be emulated, so you can call "aio_sendfile" on any type of	397	it will be emulated, so you can call "aio_sendfile" on any type of
323	filehandle regardless of the limitations of the operating system.	398	filehandle regardless of the limitations of the operating system.
324
325	Please note, however, that "aio_sendfile" can read more bytes from
326	$in_fh than are written, and there is no way to find out how many
327	bytes have been read from "aio_sendfile" alone, as "aio_sendfile"
328	only provides the number of bytes written to $out_fh. Only if the
329	result value equals $length one can assume that $length bytes have
330	been read.
331		399
332	aio_readahead $fh,$offset,$length, $callback->($retval)	400	aio_readahead $fh,$offset,$length, $callback->($retval)
333	"aio_readahead" populates the page cache with data from a file so	401	"aio_readahead" populates the page cache with data from a file so
334	that subsequent reads from that file will not block on disk I/O. The	402	that subsequent reads from that file will not block on disk I/O. The
335	$offset argument specifies the starting point from which data is to	403	$offset argument specifies the starting point from which data is to
…		…
356	Currently, the stats are always 64-bit-stats, i.e. instead of	424	Currently, the stats are always 64-bit-stats, i.e. instead of
357	returning an error when stat'ing a large file, the results will be	425	returning an error when stat'ing a large file, the results will be
358	silently truncated unless perl itself is compiled with large file	426	silently truncated unless perl itself is compiled with large file
359	support.	427	support.
360		428
		429	To help interpret the mode and dev/rdev stat values, IO::AIO offers
		430	the following constants and functions (if not implemented, the
		431	constants will be 0 and the functions will either "croak" or fall
		432	back on traditional behaviour).
		433
		434	"S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
		435	"S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
		436	"IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
		437
361	Example: Print the length of /etc/passwd:	438	Example: Print the length of /etc/passwd:
362		439
363	aio_stat "/etc/passwd", sub {	440	aio_stat "/etc/passwd", sub {
364	$_[0] and die "stat failed: $!";	441	$_[0] and die "stat failed: $!";
365	print "size is ", -s _, "\n";	442	print "size is ", -s _, "\n";
366	};	443	};
367		444
		445	aio_statvfs $fh_or_path, $callback->($statvfs)
		446	Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on
		447	whether a file handle or path was passed.
		448
		449	On success, the callback is passed a hash reference with the
		450	following members: "bsize", "frsize", "blocks", "bfree", "bavail",
		451	"files", "ffree", "favail", "fsid", "flag" and "namemax". On
		452	failure, "undef" is passed.
		453
		454	The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY"
		455	and "ST_NOSUID".
		456
		457	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		458	their correct value when available, or to 0 on systems that do not
		459	support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS",
		460	"ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE",
		461	"ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME".
		462
		463	Example: stat "/wd" and dump out the data if successful.
		464
		465	aio_statvfs "/wd", sub {
		466	my $f = $_[0]
		467	or die "statvfs: $!";
		468
		469	use Data::Dumper;
		470	say Dumper $f;
		471	};
		472
		473	# result:
		474	{
		475	bsize => 1024,
		476	bfree => 4333064312,
		477	blocks => 10253828096,
		478	files => 2050765568,
		479	flag => 4096,
		480	favail => 2042092649,
		481	bavail => 4333064312,
		482	ffree => 2042092649,
		483	namemax => 255,
		484	frsize => 1024,
		485	fsid => 1810
		486	}
		487
368	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	488	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
369	Works like perl's "utime" function (including the special case of	489	Works like perl's "utime" function (including the special case of
370	$atime and $mtime being undef). Fractional times are supported if	490	$atime and $mtime being undef). Fractional times are supported if
371	the underlying syscalls support them.	491	the underlying syscalls support them.
372		492
…		…
410		530
411	The only (POSIX-) portable way of calling this function is:	531	The only (POSIX-) portable way of calling this function is:
412		532
413	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	533	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
414		534
		535	See "aio_stat" for info about some potentially helpful extra
		536	constants and functions.
		537
415	aio_link $srcpath, $dstpath, $callback->($status)	538	aio_link $srcpath, $dstpath, $callback->($status)
416	Asynchronously create a new link to the existing object at $srcpath	539	Asynchronously create a new link to the existing object at $srcpath
417	at the path $dstpath and call the callback with the result code.	540	at the path $dstpath and call the callback with the result code.
418		541
419	aio_symlink $srcpath, $dstpath, $callback->($status)	542	aio_symlink $srcpath, $dstpath, $callback->($status)
…		…
455	The flags are a combination of the following constants, ORed	578	The flags are a combination of the following constants, ORed
456	together (the flags will also be passed to the callback, possibly	579	together (the flags will also be passed to the callback, possibly
457	modified):	580	modified):
458		581
459	IO::AIO::READDIR_DENTS	582	IO::AIO::READDIR_DENTS
460	When this flag is off, then the callback gets an arrayref with	583	When this flag is off, then the callback gets an arrayref
461	of names only (as with "aio_readdir"), otherwise it gets an	584	consisting of names only (as with "aio_readdir"), otherwise it
462	arrayref with "[$name, $type, $inode]" arrayrefs, each	585	gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
463	describing a single directory entry in more detail.	586	describing a single directory entry in more detail.
464		587
465	$name is the name of the entry.	588	$name is the name of the entry.
466		589
467	$type is one of the "IO::AIO::DT_xxx" constants:	590	$type is one of the "IO::AIO::DT_xxx" constants:
…		…
480	unspecified content on systems that do not deliver the inode	603	unspecified content on systems that do not deliver the inode
481	information.	604	information.
482		605
483	IO::AIO::READDIR_DIRS_FIRST	606	IO::AIO::READDIR_DIRS_FIRST
484	When this flag is set, then the names will be returned in an	607	When this flag is set, then the names will be returned in an
485	order where likely directories come first. This is useful when	608	order where likely directories come first, in optimal stat
486	you need to quickly find directories, or you want to find all	609	order. This is useful when you need to quickly find directories,
487	directories while avoiding to stat() each entry.	610	or you want to find all directories while avoiding to stat()
		611	each entry.
488		612
489	If the system returns type information in readdir, then this is	613	If the system returns type information in readdir, then this is
490	used to find directories directly. Otherwise, likely directories	614	used to find directories directly. Otherwise, likely directories
491	are files beginning with ".", or otherwise files with no dots,	615	are names beginning with ".", or otherwise names with no dots,
492	of which files with short names are tried first.	616	of which names with short names are tried first.
493		617
494	IO::AIO::READDIR_STAT_ORDER	618	IO::AIO::READDIR_STAT_ORDER
495	When this flag is set, then the names will be returned in an	619	When this flag is set, then the names will be returned in an
496	order suitable for stat()'ing each one. That is, when you plan	620	order suitable for stat()'ing each one. That is, when you plan
497	to stat() all files in the given directory, then the returned	621	to stat() all files in the given directory, then the returned
…		…
640	Passes 0 when everything went ok, and -1 on error.	764	Passes 0 when everything went ok, and -1 on error.
641		765
642	aio_msync $scalar, $offset = 0, $length = undef, flags = 0,	766	aio_msync $scalar, $offset = 0, $length = undef, flags = 0,
643	$callback->($status)	767	$callback->($status)
644	This is a rather advanced IO::AIO call, which only works on	768	This is a rather advanced IO::AIO call, which only works on
645	mmap(2)ed scalars (see the Sys::Mmap or Mmap modules for details on	769	mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
		770	also works on data scalars managed by the Sys::Mmap or Mmap modules,
646	this, note that the scalar must only be modified in-place while an	771	note that the scalar must only be modified in-place while an aio
647	aio operation is pending on it).	772	operation is pending on it).
648		773
649	It calls the "msync" function of your OS, if available, with the	774	It calls the "msync" function of your OS, if available, with the
650	memory area starting at $offset in the string and ending $length	775	memory area starting at $offset in the string and ending $length
651	bytes later. If $length is negative, counts from the end, and if	776	bytes later. If $length is negative, counts from the end, and if
652	$length is "undef", then it goes till the end of the string. The	777	$length is "undef", then it goes till the end of the string. The
…		…
662	inside the scalar. All caveats and parameters are the same as for	787	inside the scalar. All caveats and parameters are the same as for
663	"aio_msync", above, except for flags, which must be either 0 (which	788	"aio_msync", above, except for flags, which must be either 0 (which
664	reads all pages and ensures they are instantiated) or	789	reads all pages and ensures they are instantiated) or
665	"IO::AIO::MT_MODIFY", which modifies the memory page s(by reading	790	"IO::AIO::MT_MODIFY", which modifies the memory page s(by reading
666	and writing an octet from it, which dirties the page).	791	and writing an octet from it, which dirties the page).
		792
		793	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		794	This is a rather advanced IO::AIO call, which works best on
		795	mmap(2)ed scalars.
		796
		797	It reads in all the pages of the underlying storage into memory (if
		798	any) and locks them, so they are not getting swapped/paged out or
		799	removed.
		800
		801	If $length is undefined, then the scalar will be locked till the
		802	end.
		803
		804	On systems that do not implement "mlock", this function returns -1
		805	and sets errno to "ENOSYS".
		806
		807	Note that the corresponding "munlock" is synchronous and is
		808	documented under "MISCELLANEOUS FUNCTIONS".
		809
		810	Example: open a file, mmap and mlock it - both will be undone when
		811	$data gets destroyed.
		812
		813	open my $fh, "<", $path or die "$path: $!";
		814	my $data;
		815	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		816	aio_mlock $data; # mlock in background
		817
		818	aio_mlockall $flags, $callback->($status)
		819	Calls the "mlockall" function with the given $flags (a combination
		820	of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE").
		821
		822	On systems that do not implement "mlockall", this function returns
		823	-1 and sets errno to "ENOSYS".
		824
		825	Note that the corresponding "munlockall" is synchronous and is
		826	documented under "MISCELLANEOUS FUNCTIONS".
		827
		828	Example: asynchronously lock all current and future pages into
		829	memory.
		830
		831	aio_mlockall IO::AIO::MCL_FUTURE;
667		832
668	aio_group $callback->(...)	833	aio_group $callback->(...)
669	This is a very special aio request: Instead of doing something, it	834	This is a very special aio request: Instead of doing something, it
670	is a container for other aio requests, which is useful if you want	835	is a container for other aio requests, which is useful if you want
671	to bundle many requests into a single, composite, request with a	836	to bundle many requests into a single, composite, request with a
…		…
867		1032
868	See "poll_cb" for an example.	1033	See "poll_cb" for an example.
869		1034
870	IO::AIO::poll_cb	1035	IO::AIO::poll_cb
871	Process some outstanding events on the result pipe. You have to call	1036	Process some outstanding events on the result pipe. You have to call
872	this regularly. Returns 0 if all events could be processed, or -1 if	1037	this regularly. Returns 0 if all events could be processed (or there
873	it returned earlier for whatever reason. Returns immediately when no	1038	were no events to process), or -1 if it returned earlier for
874	events are outstanding. The amount of events processed depends on	1039	whatever reason. Returns immediately when no events are outstanding.
875	the settings of "IO::AIO::max_poll_req" and	1040	The amount of events processed depends on the settings of
876	"IO::AIO::max_poll_time".	1041	"IO::AIO::max_poll_req" and "IO::AIO::max_poll_time".
877		1042
878	If not all requests were processed for whatever reason, the	1043	If not all requests were processed for whatever reason, the
879	filehandle will still be ready when "poll_cb" returns, so normally	1044	filehandle will still be ready when "poll_cb" returns, so normally
880	you don't have to do anything special to have it called later.	1045	you don't have to do anything special to have it called later.
881		1046
		1047	Apart from calling "IO::AIO::poll_cb" when the event filehandle
		1048	becomes ready, it can be beneficial to call this function from loops
		1049	which submit a lot of requests, to make sure the results get
		1050	processed when they become available and not just when the loop is
		1051	finished and the event loop takes over again. This function returns
		1052	very fast when there are no outstanding requests.
		1053
882	Example: Install an Event watcher that automatically calls	1054	Example: Install an Event watcher that automatically calls
883	IO::AIO::poll_cb with high priority (more examples can be found in	1055	IO::AIO::poll_cb with high priority (more examples can be found in
884	the SYNOPSIS section, at the top of this document):	1056	the SYNOPSIS section, at the top of this document):
885		1057
886	Event->io (fd => IO::AIO::poll_fileno,	1058	Event->io (fd => IO::AIO::poll_fileno,
887	poll => 'r', async => 1,	1059	poll => 'r', async => 1,
888	cb => \&IO::AIO::poll_cb);	1060	cb => \&IO::AIO::poll_cb);
		1061
		1062	IO::AIO::poll_wait
		1063	If there are any outstanding requests and none of them in the result
		1064	phase, wait till the result filehandle becomes ready for reading
		1065	(simply does a "select" on the filehandle. This is useful if you
		1066	want to synchronously wait for some requests to finish).
		1067
		1068	See "nreqs" for an example.
		1069
		1070	IO::AIO::poll
		1071	Waits until some requests have been handled.
		1072
		1073	Returns the number of requests processed, but is otherwise strictly
		1074	equivalent to:
		1075
		1076	IO::AIO::poll_wait, IO::AIO::poll_cb
		1077
		1078	IO::AIO::flush
		1079	Wait till all outstanding AIO requests have been handled.
		1080
		1081	Strictly equivalent to:
		1082
		1083	IO::AIO::poll_wait, IO::AIO::poll_cb
		1084	while IO::AIO::nreqs;
889		1085
890	IO::AIO::max_poll_reqs $nreqs	1086	IO::AIO::max_poll_reqs $nreqs
891	IO::AIO::max_poll_time $seconds	1087	IO::AIO::max_poll_time $seconds
892	These set the maximum number of requests (default 0, meaning	1088	These set the maximum number of requests (default 0, meaning
893	infinity) that are being processed by "IO::AIO::poll_cb" in one	1089	infinity) that are being processed by "IO::AIO::poll_cb" in one
…		…
917	# use a low priority so other tasks have priority	1113	# use a low priority so other tasks have priority
918	Event->io (fd => IO::AIO::poll_fileno,	1114	Event->io (fd => IO::AIO::poll_fileno,
919	poll => 'r', nice => 1,	1115	poll => 'r', nice => 1,
920	cb => &IO::AIO::poll_cb);	1116	cb => &IO::AIO::poll_cb);
921		1117
922	IO::AIO::poll_wait
923	If there are any outstanding requests and none of them in the result
924	phase, wait till the result filehandle becomes ready for reading
925	(simply does a "select" on the filehandle. This is useful if you
926	want to synchronously wait for some requests to finish).
927
928	See "nreqs" for an example.
929
930	IO::AIO::poll
931	Waits until some requests have been handled.
932
933	Returns the number of requests processed, but is otherwise strictly
934	equivalent to:
935
936	IO::AIO::poll_wait, IO::AIO::poll_cb
937
938	IO::AIO::flush
939	Wait till all outstanding AIO requests have been handled.
940
941	Strictly equivalent to:
942
943	IO::AIO::poll_wait, IO::AIO::poll_cb
944	while IO::AIO::nreqs;
945
946	CONTROLLING THE NUMBER OF THREADS	1118	CONTROLLING THE NUMBER OF THREADS
947	IO::AIO::min_parallel $nthreads	1119	IO::AIO::min_parallel $nthreads
948	Set the minimum number of AIO threads to $nthreads. The current	1120	Set the minimum number of AIO threads to $nthreads. The current
949	default is 8, which means eight asynchronous operations can execute	1121	default is 8, which means eight asynchronous operations can execute
950	concurrently at any one time (the number of outstanding requests,	1122	concurrently at any one time (the number of outstanding requests,
…		…
979		1151
980	Under normal circumstances you don't need to call this function.	1152	Under normal circumstances you don't need to call this function.
981		1153
982	IO::AIO::max_idle $nthreads	1154	IO::AIO::max_idle $nthreads
983	Limit the number of threads (default: 4) that are allowed to idle	1155	Limit the number of threads (default: 4) that are allowed to idle
984	(i.e., threads that did not get a request to process within 10	1156	(i.e., threads that did not get a request to process within the idle
985	seconds). That means if a thread becomes idle while $nthreads other	1157	timeout (default: 10 seconds). That means if a thread becomes idle
986	threads are also idle, it will free its resources and exit.	1158	while $nthreads other threads are also idle, it will free its
		1159	resources and exit.
987		1160
988	This is useful when you allow a large number of threads (e.g. 100 or	1161	This is useful when you allow a large number of threads (e.g. 100 or
989	1000) to allow for extremely high load situations, but want to free	1162	1000) to allow for extremely high load situations, but want to free
990	resources under normal circumstances (1000 threads can easily	1163	resources under normal circumstances (1000 threads can easily
991	consume 30MB of RAM).	1164	consume 30MB of RAM).
992		1165
993	The default is probably ok in most situations, especially if thread	1166	The default is probably ok in most situations, especially if thread
994	creation is fast. If thread creation is very slow on your system you	1167	creation is fast. If thread creation is very slow on your system you
995	might want to use larger values.	1168	might want to use larger values.
		1169
		1170	IO::AIO::idle_timeout $seconds
		1171	Sets the minimum idle timeout (default 10) after which worker
		1172	threads are allowed to exit. SEe "IO::AIO::max_idle".
996		1173
997	IO::AIO::max_outstanding $maxreqs	1174	IO::AIO::max_outstanding $maxreqs
998	This is a very bad function to use in interactive programs because	1175	This is a very bad function to use in interactive programs because
999	it blocks, and a bad way to reduce concurrency because it is	1176	it blocks, and a bad way to reduce concurrency because it is
1000	inexact: Better use an "aio_group" together with a feed callback.	1177	inexact: Better use an "aio_group" together with a feed callback.
…		…
1042	set to non-blocking operations).	1219	set to non-blocking operations).
1043		1220
1044	Returns the number of bytes copied, or -1 on error.	1221	Returns the number of bytes copied, or -1 on error.
1045		1222
1046	IO::AIO::fadvise $fh, $offset, $len, $advice	1223	IO::AIO::fadvise $fh, $offset, $len, $advice
1047	Simply calls the "posix_fadvise" function (see it's manpage for	1224	Simply calls the "posix_fadvise" function (see its manpage for
1048	details). The following advice constants are avaiable:	1225	details). The following advice constants are avaiable:
1049	"IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL",	1226	"IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL",
1050	"IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE",	1227	"IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE",
1051	"IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED".	1228	"IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED".
1052		1229
1053	On systems that do not implement "posix_fadvise", this function	1230	On systems that do not implement "posix_fadvise", this function
1054	returns ENOSYS, otherwise the return value of "posix_fadvise".	1231	returns ENOSYS, otherwise the return value of "posix_fadvise".
		1232
		1233	IO::AIO::madvise $scalar, $offset, $len, $advice
		1234	Simply calls the "posix_madvise" function (see its manpage for
		1235	details). The following advice constants are avaiable:
		1236	"IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
		1237	"IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
		1238	"IO::AIO::MADV_DONTNEED".
		1239
		1240	On systems that do not implement "posix_madvise", this function
		1241	returns ENOSYS, otherwise the return value of "posix_madvise".
		1242
		1243	IO::AIO::mprotect $scalar, $offset, $len, $protect
		1244	Simply calls the "mprotect" function on the preferably AIO::mmap'ed
		1245	$scalar (see its manpage for details). The following protect
		1246	constants are avaiable: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
		1247	"IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
		1248
		1249	On systems that do not implement "mprotect", this function returns
		1250	ENOSYS, otherwise the return value of "mprotect".
		1251
		1252	IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1253	Memory-maps a file (or anonymous memory range) and attaches it to
		1254	the given $scalar, which will act like a string scalar.
		1255
		1256	The only operations allowed on the scalar are "substr"/"vec" that
		1257	don't change the string length, and most read-only operations such
		1258	as copying it or searching it with regexes and so on.
		1259
		1260	Anything else is unsafe and will, at best, result in memory leaks.
		1261
		1262	The memory map associated with the $scalar is automatically removed
		1263	when the $scalar is destroyed, or when the "IO::AIO::mmap" or
		1264	"IO::AIO::munmap" functions are called.
		1265
		1266	This calls the "mmap"(2) function internally. See your system's
		1267	manual page for details on the $length, $prot and $flags parameters.
		1268
		1269	The $length must be larger than zero and smaller than the actual
		1270	filesize.
		1271
		1272	$prot is a combination of "IO::AIO::PROT_NONE",
		1273	"IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
		1274	"IO::AIO::PROT_WRITE",
		1275
		1276	$flags can be a combination of "IO::AIO::MAP_SHARED" or
		1277	"IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
		1278	not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS"
		1279	(which is set to "MAP_ANON" if your system only provides this
		1280	constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
		1281	"IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or
		1282	"IO::AIO::MAP_NONBLOCK"
		1283
		1284	If $fh is "undef", then a file descriptor of -1 is passed.
		1285
		1286	$offset is the offset from the start of the file - it generally must
		1287	be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
		1288
		1289	Example:
		1290
		1291	use Digest::MD5;
		1292	use IO::AIO;
		1293
		1294	open my $fh, "<verybigfile"
		1295	or die "$!";
		1296
		1297	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1298	or die "verybigfile: $!";
		1299
		1300	my $fast_md5 = md5 $data;
		1301
		1302	IO::AIO::munmap $scalar
		1303	Removes a previous mmap and undefines the $scalar.
		1304
		1305	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1306	Calls the "munlock" function, undoing the effects of a previous
		1307	"aio_mlock" call (see its description for details).
		1308
		1309	IO::AIO::munlockall
		1310	Calls the "munlockall" function.
		1311
		1312	On systems that do not implement "munlockall", this function returns
		1313	ENOSYS, otherwise the return value of "munlockall".
		1314
		1315	EVENT LOOP INTEGRATION
		1316	It is recommended to use AnyEvent::AIO to integrate IO::AIO
		1317	automatically into many event loops:
		1318
		1319	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1320	use AnyEvent::AIO;
		1321
		1322	You can also integrate IO::AIO manually into many event loops, here are
		1323	some examples of how to do this:
		1324
		1325	# EV integration
		1326	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1327
		1328	# Event integration
		1329	Event->io (fd => IO::AIO::poll_fileno,
		1330	poll => 'r',
		1331	cb => \&IO::AIO::poll_cb);
		1332
		1333	# Glib/Gtk2 integration
		1334	add_watch Glib::IO IO::AIO::poll_fileno,
		1335	in => sub { IO::AIO::poll_cb; 1 };
		1336
		1337	# Tk integration
		1338	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1339	readable => \&IO::AIO::poll_cb);
		1340
		1341	# Danga::Socket integration
		1342	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1343	\&IO::AIO::poll_cb);
1055		1344
1056	FORK BEHAVIOUR	1345	FORK BEHAVIOUR
1057	This module should do "the right thing" when the process using it forks:	1346	This module should do "the right thing" when the process using it forks:
1058		1347
1059	Before the fork, IO::AIO enters a quiescent state where no requests can	1348	Before the fork, IO::AIO enters a quiescent state where no requests can

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing IO-AIO/README (file contents): Revision 1.41 by root, Sat Jan 2 14:24:32 2010 UTC vs. Revision 1.47 by root, Fri May 27 00:44:49 2011 UTC

Diff Legend

Comparing IO-AIO/README (file contents):
Revision 1.41 by root, Sat Jan 2 14:24:32 2010 UTC vs.
Revision 1.47 by root, Fri May 27 00:44:49 2011 UTC