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Revision 1.152 by root, Fri Jun 12 16:48:08 2009 UTC vs.
Revision 1.202 by root, Tue Jul 5 14:02:15 2011 UTC

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4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10 my $fh = shift 10 my $fh = shift
11 or die "/etc/passwd: $!"; 11 or die "/etc/passwd: $!";
12 ... 12 ...
13 }; 13 };
14 14
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26 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
27 27
28 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
29 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
30 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r',
40 cb => \&IO::AIO::poll_cb);
41
42 # Glib/Gtk2 integration
43 add_watch Glib::IO IO::AIO::poll_fileno,
44 in => sub { IO::AIO::poll_cb; 1 };
45
46 # Tk integration
47 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48 readable => \&IO::AIO::poll_cb);
49
50 # Danga::Socket integration
51 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52 \&IO::AIO::poll_cb);
53
54=head1 DESCRIPTION 31=head1 DESCRIPTION
55 32
56This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
57operating system supports. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
58 36
59Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This 39will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even 40is extremely useful for programs that need to stay interactive even
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66on a RAID volume or over NFS when you do a number of stat operations 44on a RAID volume or over NFS when you do a number of stat operations
67concurrently. 45concurrently.
68 46
69While most of this works on all types of file descriptors (for 47While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that 48example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very 49support nonblocking operation (again, sockets, pipes etc.) is
72inefficient. Use an event loop for that (such as the L<Event|Event> 50very inefficient. Use an event loop for that (such as the L<EV>
73module): IO::AIO will naturally fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
74 52
75In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
76requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
77in perl, and the threads created by this module will not be visible 55in perl, and the threads created by this module will not be visible
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87yourself, always call C<poll_cb> from within the same thread, or never 65yourself, always call C<poll_cb> from within the same thread, or never
88call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
89 67
90=head2 EXAMPLE 68=head2 EXAMPLE
91 69
92This is a simple example that uses the Event module and loads 70This is a simple example that uses the EV module and loads
93F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
94 72
95 use Fcntl; 73 use Fcntl;
96 use Event; 74 use EV;
97 use IO::AIO; 75 use IO::AIO;
98 76
99 # register the IO::AIO callback with Event 77 # register the IO::AIO callback with EV
100 Event->io (fd => IO::AIO::poll_fileno, 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103 79
104 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
106 my $fh = shift 82 my $fh = shift
107 or die "error while opening: $!"; 83 or die "error while opening: $!";
108 84
109 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
110 my $size = -s $fh; 86 my $size = -s $fh;
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119 95
120 # file contents now in $contents 96 # file contents now in $contents
121 print $contents; 97 print $contents;
122 98
123 # exit event loop and program 99 # exit event loop and program
124 Event::unloop; 100 EV::unloop;
125 }; 101 };
126 }; 102 };
127 103
128 # possibly queue up other requests, or open GUI windows, 104 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc. 105 # check for sockets etc. etc.
130 106
131 # process events as long as there are some: 107 # process events as long as there are some:
132 Event::loop; 108 EV::loop;
133 109
134=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
135 111
136Every C<aio_*> function creates a request. which is a C data structure not 112Every C<aio_*> function creates a request. which is a C data structure not
137directly visible to Perl. 113directly visible to Perl.
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187 163
188package IO::AIO; 164package IO::AIO;
189 165
190use Carp (); 166use Carp ();
191 167
192no warnings; 168use common::sense;
193use strict 'vars';
194 169
195use base 'Exporter'; 170use base 'Exporter';
196 171
197BEGIN { 172BEGIN {
198 our $VERSION = '3.21'; 173 our $VERSION = '3.93';
199 174
200 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
201 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync aio_fsync
203 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
204 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
205 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 180 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
206 aio_chmod aio_utime aio_truncate); 181 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs);
207 184
208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210 min_parallel max_parallel max_idle 187 min_parallel max_parallel max_idle idle_timeout
211 nreqs nready npending nthreads 188 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs); 189 max_poll_time max_poll_reqs
190 sendfile fadvise madvise
191 mmap munmap munlock munlockall);
213 192
214 push @AIO_REQ, qw(aio_busy); # not exported 193 push @AIO_REQ, qw(aio_busy); # not exported
215 194
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 196
218 require XSLoader; 197 require XSLoader;
219 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
220} 199}
221 200
222=head1 FUNCTIONS 201=head1 FUNCTIONS
202
203=head2 QUICK OVERVIEW
204
205This section simply lists the prototypes of the most important functions
206for quick reference. See the following sections for function-by-function
207documentation.
208
209 aio_open $pathname, $flags, $mode, $callback->($fh)
210 aio_close $fh, $callback->($status)
211 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214 aio_readahead $fh,$offset,$length, $callback->($retval)
215 aio_stat $fh_or_path, $callback->($status)
216 aio_lstat $fh, $callback->($status)
217 aio_statvfs $fh_or_path, $callback->($statvfs)
218 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
220 aio_truncate $fh_or_path, $offset, $callback->($status)
221 aio_chmod $fh_or_path, $mode, $callback->($status)
222 aio_unlink $pathname, $callback->($status)
223 aio_mknod $path, $mode, $dev, $callback->($status)
224 aio_link $srcpath, $dstpath, $callback->($status)
225 aio_symlink $srcpath, $dstpath, $callback->($status)
226 aio_readlink $path, $callback->($link)
227 aio_realpath $path, $callback->($link)
228 aio_rename $srcpath, $dstpath, $callback->($status)
229 aio_mkdir $pathname, $mode, $callback->($status)
230 aio_rmdir $pathname, $callback->($status)
231 aio_readdir $pathname, $callback->($entries)
232 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
233 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
234 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
235 aio_load $path, $data, $callback->($status)
236 aio_copy $srcpath, $dstpath, $callback->($status)
237 aio_move $srcpath, $dstpath, $callback->($status)
238 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
239 aio_rmtree $path, $callback->($status)
240 aio_sync $callback->($status)
241 aio_fsync $fh, $callback->($status)
242 aio_fdatasync $fh, $callback->($status)
243 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
244 aio_pathsync $path, $callback->($status)
245 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
247 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
248 aio_mlockall $flags, $callback->($status)
249 aio_group $callback->(...)
250 aio_nop $callback->()
251
252 $prev_pri = aioreq_pri [$pri]
253 aioreq_nice $pri_adjust
254
255 IO::AIO::poll_wait
256 IO::AIO::poll_cb
257 IO::AIO::poll
258 IO::AIO::flush
259 IO::AIO::max_poll_reqs $nreqs
260 IO::AIO::max_poll_time $seconds
261 IO::AIO::min_parallel $nthreads
262 IO::AIO::max_parallel $nthreads
263 IO::AIO::max_idle $nthreads
264 IO::AIO::idle_timeout $seconds
265 IO::AIO::max_outstanding $maxreqs
266 IO::AIO::nreqs
267 IO::AIO::nready
268 IO::AIO::npending
269
270 IO::AIO::sendfile $ofh, $ifh, $offset, $count
271 IO::AIO::fadvise $fh, $offset, $len, $advice
272 IO::AIO::madvise $scalar, $offset, $length, $advice
273 IO::AIO::mprotect $scalar, $offset, $length, $protect
274 IO::AIO::munlock $scalar, $offset = 0, $length = undef
275 IO::AIO::munlockall
223 276
224=head2 AIO REQUEST FUNCTIONS 277=head2 AIO REQUEST FUNCTIONS
225 278
226All the C<aio_*> calls are more or less thin wrappers around the syscall 279All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 280with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 360by the umask in effect then the request is being executed, so better never
308change the umask. 361change the umask.
309 362
310Example: 363Example:
311 364
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 365 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 366 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 367 print "open successful, fh is $_[0]\n";
315 ... 368 ...
316 } else { 369 } else {
317 die "open failed: $!\n"; 370 die "open failed: $!\n";
318 } 371 }
319 }; 372 };
320 373
374In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
375C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
376following POSIX and non-POSIX constants are available (missing ones on
377your system are, as usual, C<0>):
378
379C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
380C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
381C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
382
321 383
322=item aio_close $fh, $callback->($status) 384=item aio_close $fh, $callback->($status)
323 385
324Asynchronously close a file and call the callback with the result 386Asynchronously close a file and call the callback with the result
325code. 387code.
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375 437
376Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 438Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377reading at byte offset C<$in_offset>, and starts writing at the current 439reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 440file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 441than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 442other. The same C<$in_fh> works fine though, as this function does not
443move or use the file offset of C<$in_fh>.
381 444
445Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
446are written, and there is no way to find out how many more bytes have been
447read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
448number of bytes written to C<$out_fh>. Only if the result value equals
449C<$length> one can assume that C<$length> bytes have been read.
450
451Unlike with other C<aio_> functions, it makes a lot of sense to use
452C<aio_sendfile> on non-blocking sockets, as long as one end (typically
453the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
454the socket I/O will be non-blocking. Note, however, that you can run
455into a trap where C<aio_sendfile> reads some data with readahead, then
456fails to write all data, and when the socket is ready the next time, the
457data in the cache is already lost, forcing C<aio_sendfile> to again hit
458the disk. Explicit C<aio_read> + C<aio_write> let's you better control
459resource usage.
460
382This call tries to make use of a native C<sendfile> syscall to provide 461This call tries to make use of a native C<sendfile>-like syscall to
383zero-copy operation. For this to work, C<$out_fh> should refer to a 462provide zero-copy operation. For this to work, C<$out_fh> should refer to
384socket, and C<$in_fh> should refer to mmap'able file. 463a socket, and C<$in_fh> should refer to an mmap'able file.
385 464
386If the native sendfile call fails or is not implemented, it will be 465If a native sendfile cannot be found or it fails with C<ENOSYS>,
387emulated, so you can call C<aio_sendfile> on any type of filehandle 466C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
467C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
388regardless of the limitations of the operating system. 468type of filehandle regardless of the limitations of the operating system.
389 469
390Please note, however, that C<aio_sendfile> can read more bytes from 470As native sendfile syscalls (as practically any non-POSIX interface hacked
391C<$in_fh> than are written, and there is no way to find out how many 471together in a hurry to improve benchmark numbers) tend to be rather buggy
392bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 472on many systems, this implementation tries to work around some known bugs
393provides the number of bytes written to C<$out_fh>. Only if the result 473in Linux and FreeBSD kernels (probably others, too), but that might fail,
394value equals C<$length> one can assume that C<$length> bytes have been 474so you really really should check the return value of C<aio_sendfile> -
395read. 475fewre bytes than expected might have been transferred.
396 476
397 477
398=item aio_readahead $fh,$offset,$length, $callback->($retval) 478=item aio_readahead $fh,$offset,$length, $callback->($retval)
399 479
400C<aio_readahead> populates the page cache with data from a file so that 480C<aio_readahead> populates the page cache with data from a file so that
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423 503
424Currently, the stats are always 64-bit-stats, i.e. instead of returning an 504Currently, the stats are always 64-bit-stats, i.e. instead of returning an
425error when stat'ing a large file, the results will be silently truncated 505error when stat'ing a large file, the results will be silently truncated
426unless perl itself is compiled with large file support. 506unless perl itself is compiled with large file support.
427 507
508To help interpret the mode and dev/rdev stat values, IO::AIO offers the
509following constants and functions (if not implemented, the constants will
510be C<0> and the functions will either C<croak> or fall back on traditional
511behaviour).
512
513C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
514C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
515C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
516
428Example: Print the length of F</etc/passwd>: 517Example: Print the length of F</etc/passwd>:
429 518
430 aio_stat "/etc/passwd", sub { 519 aio_stat "/etc/passwd", sub {
431 $_[0] and die "stat failed: $!"; 520 $_[0] and die "stat failed: $!";
432 print "size is ", -s _, "\n"; 521 print "size is ", -s _, "\n";
433 }; 522 };
434 523
435 524
525=item aio_statvfs $fh_or_path, $callback->($statvfs)
526
527Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
528whether a file handle or path was passed.
529
530On success, the callback is passed a hash reference with the following
531members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
532C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
533is passed.
534
535The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
536C<ST_NOSUID>.
537
538The following non-POSIX IO::AIO::ST_* flag masks are defined to
539their correct value when available, or to C<0> on systems that do
540not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
541C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
542C<ST_NODIRATIME> and C<ST_RELATIME>.
543
544Example: stat C</wd> and dump out the data if successful.
545
546 aio_statvfs "/wd", sub {
547 my $f = $_[0]
548 or die "statvfs: $!";
549
550 use Data::Dumper;
551 say Dumper $f;
552 };
553
554 # result:
555 {
556 bsize => 1024,
557 bfree => 4333064312,
558 blocks => 10253828096,
559 files => 2050765568,
560 flag => 4096,
561 favail => 2042092649,
562 bavail => 4333064312,
563 ffree => 2042092649,
564 namemax => 255,
565 frsize => 1024,
566 fsid => 1810
567 }
568
569
436=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 570=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
437 571
438Works like perl's C<utime> function (including the special case of $atime 572Works like perl's C<utime> function (including the special case of $atime
439and $mtime being undef). Fractional times are supported if the underlying 573and $mtime being undef). Fractional times are supported if the underlying
440syscalls support them. 574syscalls support them.
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488 622
489The only (POSIX-) portable way of calling this function is: 623The only (POSIX-) portable way of calling this function is:
490 624
491 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 625 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
492 626
627See C<aio_stat> for info about some potentially helpful extra constants
628and functions.
493 629
494=item aio_link $srcpath, $dstpath, $callback->($status) 630=item aio_link $srcpath, $dstpath, $callback->($status)
495 631
496Asynchronously create a new link to the existing object at C<$srcpath> at 632Asynchronously create a new link to the existing object at C<$srcpath> at
497the path C<$dstpath> and call the callback with the result code. 633the path C<$dstpath> and call the callback with the result code.
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508Asynchronously read the symlink specified by C<$path> and pass it to 644Asynchronously read the symlink specified by C<$path> and pass it to
509the callback. If an error occurs, nothing or undef gets passed to the 645the callback. If an error occurs, nothing or undef gets passed to the
510callback. 646callback.
511 647
512 648
649=item aio_realpath $path, $callback->($path)
650
651Asynchronously make the path absolute and resolve any symlinks in
652C<$path>. The resulting path only consists of directories (Same as
653L<Cwd::realpath>).
654
655This request can be used to get the absolute path of the current working
656directory by passing it a path of F<.> (a single dot).
657
658
513=item aio_rename $srcpath, $dstpath, $callback->($status) 659=item aio_rename $srcpath, $dstpath, $callback->($status)
514 660
515Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 661Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
516rename(2) and call the callback with the result code. 662rename(2) and call the callback with the result code.
517 663
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550 696
551=over 4 697=over 4
552 698
553=item IO::AIO::READDIR_DENTS 699=item IO::AIO::READDIR_DENTS
554 700
555When this flag is off, then the callback gets an arrayref with of names 701When this flag is off, then the callback gets an arrayref consisting of
556only (as with C<aio_readdir>), otherwise it gets an arrayref with 702names only (as with C<aio_readdir>), otherwise it gets an arrayref with
557C<[$name, $type, $inode]> arrayrefs, each describing a single directory 703C<[$name, $type, $inode]> arrayrefs, each describing a single directory
558entry in more detail. 704entry in more detail.
559 705
560C<$name> is the name of the entry. 706C<$name> is the name of the entry.
561 707
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568C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 714C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
569know, you have to run stat yourself. Also, for speed reasons, the C<$type> 715know, you have to run stat yourself. Also, for speed reasons, the C<$type>
570scalars are read-only: you can not modify them. 716scalars are read-only: you can not modify them.
571 717
572C<$inode> is the inode number (which might not be exact on systems with 64 718C<$inode> is the inode number (which might not be exact on systems with 64
573bit inode numbers and 32 bit perls). On systems that do not deliver the 719bit inode numbers and 32 bit perls). This field has unspecified content on
574inode information, this will always be zero. 720systems that do not deliver the inode information.
575 721
576=item IO::AIO::READDIR_DIRS_FIRST 722=item IO::AIO::READDIR_DIRS_FIRST
577 723
578When this flag is set, then the names will be returned in an order where 724When this flag is set, then the names will be returned in an order where
579likely directories come first. This is useful when you need to quickly 725likely directories come first, in optimal stat order. This is useful when
580find directories, or you want to find all directories while avoiding to 726you need to quickly find directories, or you want to find all directories
581stat() each entry. 727while avoiding to stat() each entry.
582 728
583If the system returns type information in readdir, then this is used 729If the system returns type information in readdir, then this is used
584to find directories directly. Otherwise, likely directories are files 730to find directories directly. Otherwise, likely directories are names
585beginning with ".", or otherwise files with no dots, of which files with 731beginning with ".", or otherwise names with no dots, of which names with
586short names are tried first. 732short names are tried first.
587 733
588=item IO::AIO::READDIR_STAT_ORDER 734=item IO::AIO::READDIR_STAT_ORDER
589 735
590When this flag is set, then the names will be returned in an order 736When this flag is set, then the names will be returned in an order
… …
635 781
636=item aio_copy $srcpath, $dstpath, $callback->($status) 782=item aio_copy $srcpath, $dstpath, $callback->($status)
637 783
638Try to copy the I<file> (directories not supported as either source or 784Try to copy the I<file> (directories not supported as either source or
639destination) from C<$srcpath> to C<$dstpath> and call the callback with 785destination) from C<$srcpath> to C<$dstpath> and call the callback with
640the C<0> (error) or C<-1> ok. 786a status of C<0> (ok) or C<-1> (error, see C<$!>).
641 787
642This is a composite request that creates the destination file with 788This is a composite request that creates the destination file with
643mode 0200 and copies the contents of the source file into it using 789mode 0200 and copies the contents of the source file into it using
644C<aio_sendfile>, followed by restoring atime, mtime, access mode and 790C<aio_sendfile>, followed by restoring atime, mtime, access mode and
645uid/gid, in that order. 791uid/gid, in that order.
… …
657 my $grp = aio_group $cb; 803 my $grp = aio_group $cb;
658 804
659 aioreq_pri $pri; 805 aioreq_pri $pri;
660 add $grp aio_open $src, O_RDONLY, 0, sub { 806 add $grp aio_open $src, O_RDONLY, 0, sub {
661 if (my $src_fh = $_[0]) { 807 if (my $src_fh = $_[0]) {
662 my @stat = stat $src_fh; # hmm, might bock over nfs? 808 my @stat = stat $src_fh; # hmm, might block over nfs?
663 809
664 aioreq_pri $pri; 810 aioreq_pri $pri;
665 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 811 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
666 if (my $dst_fh = $_[0]) { 812 if (my $dst_fh = $_[0]) {
667 aioreq_pri $pri; 813 aioreq_pri $pri;
… …
714 860
715=item aio_move $srcpath, $dstpath, $callback->($status) 861=item aio_move $srcpath, $dstpath, $callback->($status)
716 862
717Try to move the I<file> (directories not supported as either source or 863Try to move the I<file> (directories not supported as either source or
718destination) from C<$srcpath> to C<$dstpath> and call the callback with 864destination) from C<$srcpath> to C<$dstpath> and call the callback with
719the C<0> (error) or C<-1> ok. 865a status of C<0> (ok) or C<-1> (error, see C<$!>).
720 866
721This is a composite request that tries to rename(2) the file first; if 867This is a composite request that tries to rename(2) the file first; if
722rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if 868rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
723that is successful, unlinks the C<$srcpath>. 869that is successful, unlinks the C<$srcpath>.
724 870
… …
735 if ($_[0] && $! == EXDEV) { 881 if ($_[0] && $! == EXDEV) {
736 aioreq_pri $pri; 882 aioreq_pri $pri;
737 add $grp aio_copy $src, $dst, sub { 883 add $grp aio_copy $src, $dst, sub {
738 $grp->result ($_[0]); 884 $grp->result ($_[0]);
739 885
740 if (!$_[0]) { 886 unless ($_[0]) {
741 aioreq_pri $pri; 887 aioreq_pri $pri;
742 add $grp aio_unlink $src; 888 add $grp aio_unlink $src;
743 } 889 }
744 }; 890 };
745 } else { 891 } else {
… …
958(E.g. rename). This might not work on all operating systems or have any 1104(E.g. rename). This might not work on all operating systems or have any
959specific effect, but usually it makes sure that directory changes get 1105specific effect, but usually it makes sure that directory changes get
960written to disc. It works for anything that can be opened for read-only, 1106written to disc. It works for anything that can be opened for read-only,
961not just directories. 1107not just directories.
962 1108
1109Future versions of this function might fall back to other methods when
1110C<fsync> on the directory fails (such as calling C<sync>).
1111
963Passes C<0> when everything went ok, and C<-1> on error. 1112Passes C<0> when everything went ok, and C<-1> on error.
964 1113
965=cut 1114=cut
966 1115
967sub aio_pathsync($;$) { 1116sub aio_pathsync($;$) {
… …
987 }; 1136 };
988 1137
989 $grp 1138 $grp
990} 1139}
991 1140
1141=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1142
1143This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1144scalars (see the C<IO::AIO::mmap> function, although it also works on data
1145scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1146scalar must only be modified in-place while an aio operation is pending on
1147it).
1148
1149It calls the C<msync> function of your OS, if available, with the memory
1150area starting at C<$offset> in the string and ending C<$length> bytes
1151later. If C<$length> is negative, counts from the end, and if C<$length>
1152is C<undef>, then it goes till the end of the string. The flags can be
1153a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1154C<IO::AIO::MS_SYNC>.
1155
1156=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1157
1158This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1159scalars.
1160
1161It touches (reads or writes) all memory pages in the specified
1162range inside the scalar. All caveats and parameters are the same
1163as for C<aio_msync>, above, except for flags, which must be either
1164C<0> (which reads all pages and ensures they are instantiated) or
1165C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1166writing an octet from it, which dirties the page).
1167
1168=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1169
1170This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1171scalars.
1172
1173It reads in all the pages of the underlying storage into memory (if any)
1174and locks them, so they are not getting swapped/paged out or removed.
1175
1176If C<$length> is undefined, then the scalar will be locked till the end.
1177
1178On systems that do not implement C<mlock>, this function returns C<-1>
1179and sets errno to C<ENOSYS>.
1180
1181Note that the corresponding C<munlock> is synchronous and is
1182documented under L<MISCELLANEOUS FUNCTIONS>.
1183
1184Example: open a file, mmap and mlock it - both will be undone when
1185C<$data> gets destroyed.
1186
1187 open my $fh, "<", $path or die "$path: $!";
1188 my $data;
1189 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1190 aio_mlock $data; # mlock in background
1191
1192=item aio_mlockall $flags, $callback->($status)
1193
1194Calls the C<mlockall> function with the given C<$flags> (a combination of
1195C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1196
1197On systems that do not implement C<mlockall>, this function returns C<-1>
1198and sets errno to C<ENOSYS>.
1199
1200Note that the corresponding C<munlockall> is synchronous and is
1201documented under L<MISCELLANEOUS FUNCTIONS>.
1202
1203Example: asynchronously lock all current and future pages into memory.
1204
1205 aio_mlockall IO::AIO::MCL_FUTURE;
1206
992=item aio_group $callback->(...) 1207=item aio_group $callback->(...)
993 1208
994This is a very special aio request: Instead of doing something, it is a 1209This is a very special aio request: Instead of doing something, it is a
995container for other aio requests, which is useful if you want to bundle 1210container for other aio requests, which is useful if you want to bundle
996many requests into a single, composite, request with a definite callback 1211many requests into a single, composite, request with a definite callback
… …
1131=item $grp->cancel_subs 1346=item $grp->cancel_subs
1132 1347
1133Cancel all subrequests and clears any feeder, but not the group request 1348Cancel all subrequests and clears any feeder, but not the group request
1134itself. Useful when you queued a lot of events but got a result early. 1349itself. Useful when you queued a lot of events but got a result early.
1135 1350
1351The group request will finish normally (you cannot add requests to the
1352group).
1353
1136=item $grp->result (...) 1354=item $grp->result (...)
1137 1355
1138Set the result value(s) that will be passed to the group callback when all 1356Set the result value(s) that will be passed to the group callback when all
1139subrequests have finished and set the groups errno to the current value 1357subrequests have finished and set the groups errno to the current value
1140of errno (just like calling C<errno> without an error number). By default, 1358of errno (just like calling C<errno> without an error number). By default,
… …
1208=over 4 1426=over 4
1209 1427
1210=item $fileno = IO::AIO::poll_fileno 1428=item $fileno = IO::AIO::poll_fileno
1211 1429
1212Return the I<request result pipe file descriptor>. This filehandle must be 1430Return the I<request result pipe file descriptor>. This filehandle must be
1213polled for reading by some mechanism outside this module (e.g. Event or 1431polled for reading by some mechanism outside this module (e.g. EV, Glib,
1214select, see below or the SYNOPSIS). If the pipe becomes readable you have 1432select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1215to call C<poll_cb> to check the results. 1433you have to call C<poll_cb> to check the results.
1216 1434
1217See C<poll_cb> for an example. 1435See C<poll_cb> for an example.
1218 1436
1219=item IO::AIO::poll_cb 1437=item IO::AIO::poll_cb
1220 1438
1221Process some outstanding events on the result pipe. You have to call this 1439Process some outstanding events on the result pipe. You have to call
1222regularly. Returns C<0> if all events could be processed, or C<-1> if it 1440this regularly. Returns C<0> if all events could be processed (or there
1223returned earlier for whatever reason. Returns immediately when no events 1441were no events to process), or C<-1> if it returned earlier for whatever
1224are outstanding. The amount of events processed depends on the settings of 1442reason. Returns immediately when no events are outstanding. The amount of
1225C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1443events processed depends on the settings of C<IO::AIO::max_poll_req> and
1444C<IO::AIO::max_poll_time>.
1226 1445
1227If not all requests were processed for whatever reason, the filehandle 1446If not all requests were processed for whatever reason, the filehandle
1228will still be ready when C<poll_cb> returns, so normally you don't have to 1447will still be ready when C<poll_cb> returns, so normally you don't have to
1229do anything special to have it called later. 1448do anything special to have it called later.
1230 1449
1450Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1451ready, it can be beneficial to call this function from loops which submit
1452a lot of requests, to make sure the results get processed when they become
1453available and not just when the loop is finished and the event loop takes
1454over again. This function returns very fast when there are no outstanding
1455requests.
1456
1231Example: Install an Event watcher that automatically calls 1457Example: Install an Event watcher that automatically calls
1232IO::AIO::poll_cb with high priority: 1458IO::AIO::poll_cb with high priority (more examples can be found in the
1459SYNOPSIS section, at the top of this document):
1233 1460
1234 Event->io (fd => IO::AIO::poll_fileno, 1461 Event->io (fd => IO::AIO::poll_fileno,
1235 poll => 'r', async => 1, 1462 poll => 'r', async => 1,
1236 cb => \&IO::AIO::poll_cb); 1463 cb => \&IO::AIO::poll_cb);
1464
1465=item IO::AIO::poll_wait
1466
1467If there are any outstanding requests and none of them in the result
1468phase, wait till the result filehandle becomes ready for reading (simply
1469does a C<select> on the filehandle. This is useful if you want to
1470synchronously wait for some requests to finish).
1471
1472See C<nreqs> for an example.
1473
1474=item IO::AIO::poll
1475
1476Waits until some requests have been handled.
1477
1478Returns the number of requests processed, but is otherwise strictly
1479equivalent to:
1480
1481 IO::AIO::poll_wait, IO::AIO::poll_cb
1482
1483=item IO::AIO::flush
1484
1485Wait till all outstanding AIO requests have been handled.
1486
1487Strictly equivalent to:
1488
1489 IO::AIO::poll_wait, IO::AIO::poll_cb
1490 while IO::AIO::nreqs;
1237 1491
1238=item IO::AIO::max_poll_reqs $nreqs 1492=item IO::AIO::max_poll_reqs $nreqs
1239 1493
1240=item IO::AIO::max_poll_time $seconds 1494=item IO::AIO::max_poll_time $seconds
1241 1495
… …
1266 # use a low priority so other tasks have priority 1520 # use a low priority so other tasks have priority
1267 Event->io (fd => IO::AIO::poll_fileno, 1521 Event->io (fd => IO::AIO::poll_fileno,
1268 poll => 'r', nice => 1, 1522 poll => 'r', nice => 1,
1269 cb => &IO::AIO::poll_cb); 1523 cb => &IO::AIO::poll_cb);
1270 1524
1271=item IO::AIO::poll_wait
1272
1273If there are any outstanding requests and none of them in the result
1274phase, wait till the result filehandle becomes ready for reading (simply
1275does a C<select> on the filehandle. This is useful if you want to
1276synchronously wait for some requests to finish).
1277
1278See C<nreqs> for an example.
1279
1280=item IO::AIO::poll
1281
1282Waits until some requests have been handled.
1283
1284Returns the number of requests processed, but is otherwise strictly
1285equivalent to:
1286
1287 IO::AIO::poll_wait, IO::AIO::poll_cb
1288
1289=item IO::AIO::flush
1290
1291Wait till all outstanding AIO requests have been handled.
1292
1293Strictly equivalent to:
1294
1295 IO::AIO::poll_wait, IO::AIO::poll_cb
1296 while IO::AIO::nreqs;
1297
1298=back 1525=back
1299 1526
1300=head3 CONTROLLING THE NUMBER OF THREADS 1527=head3 CONTROLLING THE NUMBER OF THREADS
1301 1528
1302=over 1529=over
… …
1335 1562
1336Under normal circumstances you don't need to call this function. 1563Under normal circumstances you don't need to call this function.
1337 1564
1338=item IO::AIO::max_idle $nthreads 1565=item IO::AIO::max_idle $nthreads
1339 1566
1340Limit the number of threads (default: 4) that are allowed to idle (i.e., 1567Limit the number of threads (default: 4) that are allowed to idle
1341threads that did not get a request to process within 10 seconds). That 1568(i.e., threads that did not get a request to process within the idle
1342means if a thread becomes idle while C<$nthreads> other threads are also 1569timeout (default: 10 seconds). That means if a thread becomes idle while
1343idle, it will free its resources and exit. 1570C<$nthreads> other threads are also idle, it will free its resources and
1571exit.
1344 1572
1345This is useful when you allow a large number of threads (e.g. 100 or 1000) 1573This is useful when you allow a large number of threads (e.g. 100 or 1000)
1346to allow for extremely high load situations, but want to free resources 1574to allow for extremely high load situations, but want to free resources
1347under normal circumstances (1000 threads can easily consume 30MB of RAM). 1575under normal circumstances (1000 threads can easily consume 30MB of RAM).
1348 1576
1349The default is probably ok in most situations, especially if thread 1577The default is probably ok in most situations, especially if thread
1350creation is fast. If thread creation is very slow on your system you might 1578creation is fast. If thread creation is very slow on your system you might
1351want to use larger values. 1579want to use larger values.
1352 1580
1581=item IO::AIO::idle_timeout $seconds
1582
1583Sets the minimum idle timeout (default 10) after which worker threads are
1584allowed to exit. SEe C<IO::AIO::max_idle>.
1585
1353=item IO::AIO::max_outstanding $maxreqs 1586=item IO::AIO::max_outstanding $maxreqs
1587
1588Sets the maximum number of outstanding requests to C<$nreqs>. If
1589you do queue up more than this number of requests, the next call to
1590C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1591C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1592longer exceeded.
1593
1594In other words, this setting does not enforce a queue limit, but can be
1595used to make poll functions block if the limit is exceeded.
1354 1596
1355This is a very bad function to use in interactive programs because it 1597This is a very bad function to use in interactive programs because it
1356blocks, and a bad way to reduce concurrency because it is inexact: Better 1598blocks, and a bad way to reduce concurrency because it is inexact: Better
1357use an C<aio_group> together with a feed callback. 1599use an C<aio_group> together with a feed callback.
1358 1600
1359Sets the maximum number of outstanding requests to C<$nreqs>. If you 1601It's main use is in scripts without an event loop - when you want to stat
1360do queue up more than this number of requests, the next call to the 1602a lot of files, you can write somehting like this:
1361C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1362function will block until the limit is no longer exceeded.
1363 1603
1364The default value is very large, so there is no practical limit on the 1604 IO::AIO::max_outstanding 32;
1365number of outstanding requests.
1366 1605
1367You can still queue as many requests as you want. Therefore, 1606 for my $path (...) {
1368C<max_outstanding> is mainly useful in simple scripts (with low values) or 1607 aio_stat $path , ...;
1369as a stop gap to shield against fatal memory overflow (with large values). 1608 IO::AIO::poll_cb;
1609 }
1610
1611 IO::AIO::flush;
1612
1613The call to C<poll_cb> inside the loop will normally return instantly, but
1614as soon as more thna C<32> reqeusts are in-flight, it will block until
1615some requests have been handled. This keeps the loop from pushing a large
1616number of C<aio_stat> requests onto the queue.
1617
1618The default value for C<max_outstanding> is very large, so there is no
1619practical limit on the number of outstanding requests.
1370 1620
1371=back 1621=back
1372 1622
1373=head3 STATISTICAL INFORMATION 1623=head3 STATISTICAL INFORMATION
1374 1624
… …
1394Returns the number of requests currently in the pending state (executed, 1644Returns the number of requests currently in the pending state (executed,
1395but not yet processed by poll_cb). 1645but not yet processed by poll_cb).
1396 1646
1397=back 1647=back
1398 1648
1649=head3 MISCELLANEOUS FUNCTIONS
1650
1651IO::AIO implements some functions that might be useful, but are not
1652asynchronous.
1653
1654=over 4
1655
1656=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1657
1658Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1659but is blocking (this makes most sense if you know the input data is
1660likely cached already and the output filehandle is set to non-blocking
1661operations).
1662
1663Returns the number of bytes copied, or C<-1> on error.
1664
1665=item IO::AIO::fadvise $fh, $offset, $len, $advice
1666
1667Simply calls the C<posix_fadvise> function (see its
1668manpage for details). The following advice constants are
1669avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1670C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1671C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1672
1673On systems that do not implement C<posix_fadvise>, this function returns
1674ENOSYS, otherwise the return value of C<posix_fadvise>.
1675
1676=item IO::AIO::madvise $scalar, $offset, $len, $advice
1677
1678Simply calls the C<posix_madvise> function (see its
1679manpage for details). The following advice constants are
1680avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1681C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1682
1683On systems that do not implement C<posix_madvise>, this function returns
1684ENOSYS, otherwise the return value of C<posix_madvise>.
1685
1686=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1687
1688Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1689$scalar (see its manpage for details). The following protect
1690constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1691C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1692
1693On systems that do not implement C<mprotect>, this function returns
1694ENOSYS, otherwise the return value of C<mprotect>.
1695
1696=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1697
1698Memory-maps a file (or anonymous memory range) and attaches it to the
1699given C<$scalar>, which will act like a string scalar.
1700
1701The only operations allowed on the scalar are C<substr>/C<vec> that don't
1702change the string length, and most read-only operations such as copying it
1703or searching it with regexes and so on.
1704
1705Anything else is unsafe and will, at best, result in memory leaks.
1706
1707The memory map associated with the C<$scalar> is automatically removed
1708when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1709C<IO::AIO::munmap> functions are called.
1710
1711This calls the C<mmap>(2) function internally. See your system's manual
1712page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1713
1714The C<$length> must be larger than zero and smaller than the actual
1715filesize.
1716
1717C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1718C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1719
1720C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1721C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1722not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1723(which is set to C<MAP_ANON> if your system only provides this
1724constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1725C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1726C<IO::AIO::MAP_NONBLOCK>
1727
1728If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1729
1730C<$offset> is the offset from the start of the file - it generally must be
1731a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1732
1733Example:
1734
1735 use Digest::MD5;
1736 use IO::AIO;
1737
1738 open my $fh, "<verybigfile"
1739 or die "$!";
1740
1741 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1742 or die "verybigfile: $!";
1743
1744 my $fast_md5 = md5 $data;
1745
1746=item IO::AIO::munmap $scalar
1747
1748Removes a previous mmap and undefines the C<$scalar>.
1749
1750=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1751
1752Calls the C<munlock> function, undoing the effects of a previous
1753C<aio_mlock> call (see its description for details).
1754
1755=item IO::AIO::munlockall
1756
1757Calls the C<munlockall> function.
1758
1759On systems that do not implement C<munlockall>, this function returns
1760ENOSYS, otherwise the return value of C<munlockall>.
1761
1762=back
1763
1399=cut 1764=cut
1400 1765
1401min_parallel 8; 1766min_parallel 8;
1402 1767
1403END { flush } 1768END { flush }
1404 1769
14051; 17701;
1406 1771
1772=head1 EVENT LOOP INTEGRATION
1773
1774It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1775automatically into many event loops:
1776
1777 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1778 use AnyEvent::AIO;
1779
1780You can also integrate IO::AIO manually into many event loops, here are
1781some examples of how to do this:
1782
1783 # EV integration
1784 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1785
1786 # Event integration
1787 Event->io (fd => IO::AIO::poll_fileno,
1788 poll => 'r',
1789 cb => \&IO::AIO::poll_cb);
1790
1791 # Glib/Gtk2 integration
1792 add_watch Glib::IO IO::AIO::poll_fileno,
1793 in => sub { IO::AIO::poll_cb; 1 };
1794
1795 # Tk integration
1796 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1797 readable => \&IO::AIO::poll_cb);
1798
1799 # Danga::Socket integration
1800 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1801 \&IO::AIO::poll_cb);
1802
1407=head2 FORK BEHAVIOUR 1803=head2 FORK BEHAVIOUR
1408 1804
1409This module should do "the right thing" when the process using it forks: 1805Usage of pthreads in a program changes the semantics of fork
1806considerably. Specifically, only async-safe functions can be called after
1807fork. Perl doesn't know about this, so in general, you cannot call fork
1808with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1809but many other extensions and (for inexplicable reasons) perl itself often
1810is linked against pthreads, so this limitation applies.
1410 1811
1411Before the fork, IO::AIO enters a quiescent state where no requests 1812Some operating systems have extensions that allow safe use of fork, and
1412can be added in other threads and no results will be processed. After 1813this module should do "the right thing" on those, and tries on others. At
1413the fork the parent simply leaves the quiescent state and continues 1814the time of this writing (2011) only GNU/Linux supports these extensions
1414request/result processing, while the child frees the request/result queue 1815to POSIX.
1415(so that the requests started before the fork will only be handled in the
1416parent). Threads will be started on demand until the limit set in the
1417parent process has been reached again.
1418
1419In short: the parent will, after a short pause, continue as if fork had
1420not been called, while the child will act as if IO::AIO has not been used
1421yet.
1422 1816
1423=head2 MEMORY USAGE 1817=head2 MEMORY USAGE
1424 1818
1425Per-request usage: 1819Per-request usage:
1426 1820

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