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Revision 1.149 by root, Sat Jun 6 18:19:35 2009 UTC vs.
Revision 1.201 by root, Tue Jul 5 09:24:11 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 = '3.2'; 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.
653
654This request can be used to get the absolute path of the current working
655directory by passing it a path of F<.> (a single dot).
656
657
513=item aio_rename $srcpath, $dstpath, $callback->($status) 658=item aio_rename $srcpath, $dstpath, $callback->($status)
514 659
515Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 660Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
516rename(2) and call the callback with the result code. 661rename(2) and call the callback with the result code.
517 662
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548The flags are a combination of the following constants, ORed together (the 693The flags are a combination of the following constants, ORed together (the
549flags will also be passed to the callback, possibly modified): 694flags will also be passed to the callback, possibly modified):
550 695
551=over 4 696=over 4
552 697
553=item AIO::READDIR_DENTS 698=item IO::AIO::READDIR_DENTS
554 699
555When this flag is off, then the callback gets an arrayref with of names 700When this flag is off, then the callback gets an arrayref consisting of
556only (as with C<aio_readdir>), otherwise it gets an arrayref with 701names only (as with C<aio_readdir>), otherwise it gets an arrayref with
557C<[$name, $inode, $type]> arrayrefs, each describing a single directory 702C<[$name, $type, $inode]> arrayrefs, each describing a single directory
558entry in more detail. 703entry in more detail.
559 704
560C<$name> is the name of the entry. 705C<$name> is the name of the entry.
561 706
562C<$inode> is the inode number (which might not be exact on systems with 64
563bit inode numbers and 32 bit perls). On systems that do not deliver the
564inode information, this will always be zero.
565
566C<$type> is one of the C<AIO::DT_xxx> constants: 707C<$type> is one of the C<IO::AIO::DT_xxx> constants:
567 708
568C<AIO::DT_UNKNOWN>, C<AIO::DT_FIFO>, C<AIO::DT_CHR>, C<AIO::DT_DIR>, 709C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
569C<AIO::DT_BLK>, C<AIO::DT_REG>, C<AIO::DT_LNK>, C<AIO::DT_SOCK>, 710C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
570C<AIO::DT_WHT>. 711C<IO::AIO::DT_WHT>.
571 712
572C<AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 713C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
573know, you have to run stat yourself. Also, for speed reasons, the C<$type> 714know, you have to run stat yourself. Also, for speed reasons, the C<$type>
574scalars are read-only: you can not modify them. 715scalars are read-only: you can not modify them.
575 716
717C<$inode> is the inode number (which might not be exact on systems with 64
718bit inode numbers and 32 bit perls). This field has unspecified content on
719systems that do not deliver the inode information.
720
576=item AIO::READDIR_DIRS_FIRST 721=item IO::AIO::READDIR_DIRS_FIRST
577 722
578When this flag is set, then the names will be returned in an order where 723When 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 724likely directories come first, in optimal stat order. This is useful when
580find directories, or you want to find all directories while avoiding to 725you need to quickly find directories, or you want to find all directories
581stat() each entry. 726while avoiding to stat() each entry.
582 727
583If the system returns type information in readdir, then this is used 728If the system returns type information in readdir, then this is used
584to find directories directly. Otherwise, likely directories are files 729to find directories directly. Otherwise, likely directories are names
585beginning with ".", or otherwise files with no dots, of which files with 730beginning with ".", or otherwise names with no dots, of which names with
586short names are tried first. 731short names are tried first.
587 732
588=item AIO::READDIR_STAT_ORDER 733=item IO::AIO::READDIR_STAT_ORDER
589 734
590When this flag is set, then the names will be returned in an order 735When this flag is set, then the names will be returned in an order
591suitable for stat()'ing each one. That is, when you plan to stat() 736suitable for stat()'ing each one. That is, when you plan to stat()
592all files in the given directory, then the returned order will likely 737all files in the given directory, then the returned order will likely
593be fastest. 738be fastest.
594 739
595If both this flag and IO::READDIR_DIRS_FIRST are specified, then the 740If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
596likely dirs come first, resulting in a less optimal stat order. 741the likely dirs come first, resulting in a less optimal stat order.
597 742
598=item AIO::READDIR_FOUND_UNKNOWN 743=item IO::AIO::READDIR_FOUND_UNKNOWN
599 744
600This flag should not be set when calling C<aio_readdirx>. Instead, it 745This flag should not be set when calling C<aio_readdirx>. Instead, it
601is being set by C<aio_readdirx>, when any of the C<$type>'s found were 746is being set by C<aio_readdirx>, when any of the C<$type>'s found were
602C<AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 747C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
603C<$type>'s are known, which can be used to speed up some algorithms. 748C<$type>'s are known, which can be used to speed up some algorithms.
604 749
605=back 750=back
606 751
607 752
… …
635 780
636=item aio_copy $srcpath, $dstpath, $callback->($status) 781=item aio_copy $srcpath, $dstpath, $callback->($status)
637 782
638Try to copy the I<file> (directories not supported as either source or 783Try to copy the I<file> (directories not supported as either source or
639destination) from C<$srcpath> to C<$dstpath> and call the callback with 784destination) from C<$srcpath> to C<$dstpath> and call the callback with
640the C<0> (error) or C<-1> ok. 785a status of C<0> (ok) or C<-1> (error, see C<$!>).
641 786
642This is a composite request that creates the destination file with 787This is a composite request that creates the destination file with
643mode 0200 and copies the contents of the source file into it using 788mode 0200 and copies the contents of the source file into it using
644C<aio_sendfile>, followed by restoring atime, mtime, access mode and 789C<aio_sendfile>, followed by restoring atime, mtime, access mode and
645uid/gid, in that order. 790uid/gid, in that order.
… …
657 my $grp = aio_group $cb; 802 my $grp = aio_group $cb;
658 803
659 aioreq_pri $pri; 804 aioreq_pri $pri;
660 add $grp aio_open $src, O_RDONLY, 0, sub { 805 add $grp aio_open $src, O_RDONLY, 0, sub {
661 if (my $src_fh = $_[0]) { 806 if (my $src_fh = $_[0]) {
662 my @stat = stat $src_fh; # hmm, might bock over nfs? 807 my @stat = stat $src_fh; # hmm, might block over nfs?
663 808
664 aioreq_pri $pri; 809 aioreq_pri $pri;
665 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 810 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
666 if (my $dst_fh = $_[0]) { 811 if (my $dst_fh = $_[0]) {
667 aioreq_pri $pri; 812 aioreq_pri $pri;
… …
714 859
715=item aio_move $srcpath, $dstpath, $callback->($status) 860=item aio_move $srcpath, $dstpath, $callback->($status)
716 861
717Try to move the I<file> (directories not supported as either source or 862Try to move the I<file> (directories not supported as either source or
718destination) from C<$srcpath> to C<$dstpath> and call the callback with 863destination) from C<$srcpath> to C<$dstpath> and call the callback with
719the C<0> (error) or C<-1> ok. 864a status of C<0> (ok) or C<-1> (error, see C<$!>).
720 865
721This is a composite request that tries to rename(2) the file first; if 866This is a composite request that tries to rename(2) the file first; if
722rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if 867rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
723that is successful, unlinks the C<$srcpath>. 868that is successful, unlinks the C<$srcpath>.
724 869
… …
735 if ($_[0] && $! == EXDEV) { 880 if ($_[0] && $! == EXDEV) {
736 aioreq_pri $pri; 881 aioreq_pri $pri;
737 add $grp aio_copy $src, $dst, sub { 882 add $grp aio_copy $src, $dst, sub {
738 $grp->result ($_[0]); 883 $grp->result ($_[0]);
739 884
740 if (!$_[0]) { 885 unless ($_[0]) {
741 aioreq_pri $pri; 886 aioreq_pri $pri;
742 add $grp aio_unlink $src; 887 add $grp aio_unlink $src;
743 } 888 }
744 }; 889 };
745 } else { 890 } else {
… …
840 # take the slow route if anything looks fishy 985 # take the slow route if anything looks fishy
841 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 986 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
842 $ndirs = -1; 987 $ndirs = -1;
843 } else { 988 } else {
844 # if nlink == 2, we are finished 989 # if nlink == 2, we are finished
845 # on non-posix-fs's, we rely on nlink < 2 990 # for non-posix-fs's, we rely on nlink < 2
846 $ndirs = (stat _)[3] - 2 991 $ndirs = (stat _)[3] - 2
847 or return $grp->result ([], $entries); 992 or return $grp->result ([], $entries);
848 } 993 }
849 994
850 my (@dirs, @nondirs); 995 my (@dirs, @nondirs);
… …
854 }; 999 };
855 1000
856 limit $statgrp $maxreq; 1001 limit $statgrp $maxreq;
857 feed $statgrp sub { 1002 feed $statgrp sub {
858 return unless @$entries; 1003 return unless @$entries;
859 my $entry = pop @$entries; 1004 my $entry = shift @$entries;
860 1005
861 aioreq_pri $pri; 1006 aioreq_pri $pri;
862 add $statgrp aio_stat "$path/$entry/.", sub { 1007 add $statgrp aio_stat "$path/$entry/.", sub {
863 if ($_[0] < 0) { 1008 if ($_[0] < 0) {
864 push @nondirs, $entry; 1009 push @nondirs, $entry;
… …
958(E.g. rename). This might not work on all operating systems or have any 1103(E.g. rename). This might not work on all operating systems or have any
959specific effect, but usually it makes sure that directory changes get 1104specific effect, but usually it makes sure that directory changes get
960written to disc. It works for anything that can be opened for read-only, 1105written to disc. It works for anything that can be opened for read-only,
961not just directories. 1106not just directories.
962 1107
1108Future versions of this function might fall back to other methods when
1109C<fsync> on the directory fails (such as calling C<sync>).
1110
963Passes C<0> when everything went ok, and C<-1> on error. 1111Passes C<0> when everything went ok, and C<-1> on error.
964 1112
965=cut 1113=cut
966 1114
967sub aio_pathsync($;$) { 1115sub aio_pathsync($;$) {
… …
987 }; 1135 };
988 1136
989 $grp 1137 $grp
990} 1138}
991 1139
1140=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1141
1142This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1143scalars (see the C<IO::AIO::mmap> function, although it also works on data
1144scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1145scalar must only be modified in-place while an aio operation is pending on
1146it).
1147
1148It calls the C<msync> function of your OS, if available, with the memory
1149area starting at C<$offset> in the string and ending C<$length> bytes
1150later. If C<$length> is negative, counts from the end, and if C<$length>
1151is C<undef>, then it goes till the end of the string. The flags can be
1152a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1153C<IO::AIO::MS_SYNC>.
1154
1155=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1156
1157This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1158scalars.
1159
1160It touches (reads or writes) all memory pages in the specified
1161range inside the scalar. All caveats and parameters are the same
1162as for C<aio_msync>, above, except for flags, which must be either
1163C<0> (which reads all pages and ensures they are instantiated) or
1164C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1165writing an octet from it, which dirties the page).
1166
1167=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1168
1169This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170scalars.
1171
1172It reads in all the pages of the underlying storage into memory (if any)
1173and locks them, so they are not getting swapped/paged out or removed.
1174
1175If C<$length> is undefined, then the scalar will be locked till the end.
1176
1177On systems that do not implement C<mlock>, this function returns C<-1>
1178and sets errno to C<ENOSYS>.
1179
1180Note that the corresponding C<munlock> is synchronous and is
1181documented under L<MISCELLANEOUS FUNCTIONS>.
1182
1183Example: open a file, mmap and mlock it - both will be undone when
1184C<$data> gets destroyed.
1185
1186 open my $fh, "<", $path or die "$path: $!";
1187 my $data;
1188 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1189 aio_mlock $data; # mlock in background
1190
1191=item aio_mlockall $flags, $callback->($status)
1192
1193Calls the C<mlockall> function with the given C<$flags> (a combination of
1194C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1195
1196On systems that do not implement C<mlockall>, this function returns C<-1>
1197and sets errno to C<ENOSYS>.
1198
1199Note that the corresponding C<munlockall> is synchronous and is
1200documented under L<MISCELLANEOUS FUNCTIONS>.
1201
1202Example: asynchronously lock all current and future pages into memory.
1203
1204 aio_mlockall IO::AIO::MCL_FUTURE;
1205
992=item aio_group $callback->(...) 1206=item aio_group $callback->(...)
993 1207
994This is a very special aio request: Instead of doing something, it is a 1208This 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 1209container for other aio requests, which is useful if you want to bundle
996many requests into a single, composite, request with a definite callback 1210many requests into a single, composite, request with a definite callback
… …
1045=item cancel $req 1259=item cancel $req
1046 1260
1047Cancels the request, if possible. Has the effect of skipping execution 1261Cancels the request, if possible. Has the effect of skipping execution
1048when entering the B<execute> state and skipping calling the callback when 1262when entering the B<execute> state and skipping calling the callback when
1049entering the the B<result> state, but will leave the request otherwise 1263entering the the B<result> state, but will leave the request otherwise
1050untouched. That means that requests that currently execute will not be 1264untouched (with the exception of readdir). That means that requests that
1051stopped and resources held by the request will not be freed prematurely. 1265currently execute will not be stopped and resources held by the request
1266will not be freed prematurely.
1052 1267
1053=item cb $req $callback->(...) 1268=item cb $req $callback->(...)
1054 1269
1055Replace (or simply set) the callback registered to the request. 1270Replace (or simply set) the callback registered to the request.
1056 1271
… …
1129 1344
1130=item $grp->cancel_subs 1345=item $grp->cancel_subs
1131 1346
1132Cancel all subrequests and clears any feeder, but not the group request 1347Cancel all subrequests and clears any feeder, but not the group request
1133itself. Useful when you queued a lot of events but got a result early. 1348itself. Useful when you queued a lot of events but got a result early.
1349
1350The group request will finish normally (you cannot add requests to the
1351group).
1134 1352
1135=item $grp->result (...) 1353=item $grp->result (...)
1136 1354
1137Set the result value(s) that will be passed to the group callback when all 1355Set the result value(s) that will be passed to the group callback when all
1138subrequests have finished and set the groups errno to the current value 1356subrequests have finished and set the groups errno to the current value
… …
1207=over 4 1425=over 4
1208 1426
1209=item $fileno = IO::AIO::poll_fileno 1427=item $fileno = IO::AIO::poll_fileno
1210 1428
1211Return the I<request result pipe file descriptor>. This filehandle must be 1429Return the I<request result pipe file descriptor>. This filehandle must be
1212polled for reading by some mechanism outside this module (e.g. Event or 1430polled for reading by some mechanism outside this module (e.g. EV, Glib,
1213select, see below or the SYNOPSIS). If the pipe becomes readable you have 1431select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1214to call C<poll_cb> to check the results. 1432you have to call C<poll_cb> to check the results.
1215 1433
1216See C<poll_cb> for an example. 1434See C<poll_cb> for an example.
1217 1435
1218=item IO::AIO::poll_cb 1436=item IO::AIO::poll_cb
1219 1437
1220Process some outstanding events on the result pipe. You have to call this 1438Process some outstanding events on the result pipe. You have to call
1221regularly. Returns C<0> if all events could be processed, or C<-1> if it 1439this regularly. Returns C<0> if all events could be processed (or there
1222returned earlier for whatever reason. Returns immediately when no events 1440were no events to process), or C<-1> if it returned earlier for whatever
1223are outstanding. The amount of events processed depends on the settings of 1441reason. Returns immediately when no events are outstanding. The amount of
1224C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1442events processed depends on the settings of C<IO::AIO::max_poll_req> and
1443C<IO::AIO::max_poll_time>.
1225 1444
1226If not all requests were processed for whatever reason, the filehandle 1445If not all requests were processed for whatever reason, the filehandle
1227will still be ready when C<poll_cb> returns, so normally you don't have to 1446will still be ready when C<poll_cb> returns, so normally you don't have to
1228do anything special to have it called later. 1447do anything special to have it called later.
1229 1448
1449Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1450ready, it can be beneficial to call this function from loops which submit
1451a lot of requests, to make sure the results get processed when they become
1452available and not just when the loop is finished and the event loop takes
1453over again. This function returns very fast when there are no outstanding
1454requests.
1455
1230Example: Install an Event watcher that automatically calls 1456Example: Install an Event watcher that automatically calls
1231IO::AIO::poll_cb with high priority: 1457IO::AIO::poll_cb with high priority (more examples can be found in the
1458SYNOPSIS section, at the top of this document):
1232 1459
1233 Event->io (fd => IO::AIO::poll_fileno, 1460 Event->io (fd => IO::AIO::poll_fileno,
1234 poll => 'r', async => 1, 1461 poll => 'r', async => 1,
1235 cb => \&IO::AIO::poll_cb); 1462 cb => \&IO::AIO::poll_cb);
1463
1464=item IO::AIO::poll_wait
1465
1466If there are any outstanding requests and none of them in the result
1467phase, wait till the result filehandle becomes ready for reading (simply
1468does a C<select> on the filehandle. This is useful if you want to
1469synchronously wait for some requests to finish).
1470
1471See C<nreqs> for an example.
1472
1473=item IO::AIO::poll
1474
1475Waits until some requests have been handled.
1476
1477Returns the number of requests processed, but is otherwise strictly
1478equivalent to:
1479
1480 IO::AIO::poll_wait, IO::AIO::poll_cb
1481
1482=item IO::AIO::flush
1483
1484Wait till all outstanding AIO requests have been handled.
1485
1486Strictly equivalent to:
1487
1488 IO::AIO::poll_wait, IO::AIO::poll_cb
1489 while IO::AIO::nreqs;
1236 1490
1237=item IO::AIO::max_poll_reqs $nreqs 1491=item IO::AIO::max_poll_reqs $nreqs
1238 1492
1239=item IO::AIO::max_poll_time $seconds 1493=item IO::AIO::max_poll_time $seconds
1240 1494
… …
1265 # use a low priority so other tasks have priority 1519 # use a low priority so other tasks have priority
1266 Event->io (fd => IO::AIO::poll_fileno, 1520 Event->io (fd => IO::AIO::poll_fileno,
1267 poll => 'r', nice => 1, 1521 poll => 'r', nice => 1,
1268 cb => &IO::AIO::poll_cb); 1522 cb => &IO::AIO::poll_cb);
1269 1523
1270=item IO::AIO::poll_wait
1271
1272If there are any outstanding requests and none of them in the result
1273phase, wait till the result filehandle becomes ready for reading (simply
1274does a C<select> on the filehandle. This is useful if you want to
1275synchronously wait for some requests to finish).
1276
1277See C<nreqs> for an example.
1278
1279=item IO::AIO::poll
1280
1281Waits until some requests have been handled.
1282
1283Returns the number of requests processed, but is otherwise strictly
1284equivalent to:
1285
1286 IO::AIO::poll_wait, IO::AIO::poll_cb
1287
1288=item IO::AIO::flush
1289
1290Wait till all outstanding AIO requests have been handled.
1291
1292Strictly equivalent to:
1293
1294 IO::AIO::poll_wait, IO::AIO::poll_cb
1295 while IO::AIO::nreqs;
1296
1297=back 1524=back
1298 1525
1299=head3 CONTROLLING THE NUMBER OF THREADS 1526=head3 CONTROLLING THE NUMBER OF THREADS
1300 1527
1301=over 1528=over
… …
1334 1561
1335Under normal circumstances you don't need to call this function. 1562Under normal circumstances you don't need to call this function.
1336 1563
1337=item IO::AIO::max_idle $nthreads 1564=item IO::AIO::max_idle $nthreads
1338 1565
1339Limit the number of threads (default: 4) that are allowed to idle (i.e., 1566Limit the number of threads (default: 4) that are allowed to idle
1340threads that did not get a request to process within 10 seconds). That 1567(i.e., threads that did not get a request to process within the idle
1341means if a thread becomes idle while C<$nthreads> other threads are also 1568timeout (default: 10 seconds). That means if a thread becomes idle while
1342idle, it will free its resources and exit. 1569C<$nthreads> other threads are also idle, it will free its resources and
1570exit.
1343 1571
1344This is useful when you allow a large number of threads (e.g. 100 or 1000) 1572This is useful when you allow a large number of threads (e.g. 100 or 1000)
1345to allow for extremely high load situations, but want to free resources 1573to allow for extremely high load situations, but want to free resources
1346under normal circumstances (1000 threads can easily consume 30MB of RAM). 1574under normal circumstances (1000 threads can easily consume 30MB of RAM).
1347 1575
1348The default is probably ok in most situations, especially if thread 1576The default is probably ok in most situations, especially if thread
1349creation is fast. If thread creation is very slow on your system you might 1577creation is fast. If thread creation is very slow on your system you might
1350want to use larger values. 1578want to use larger values.
1351 1579
1580=item IO::AIO::idle_timeout $seconds
1581
1582Sets the minimum idle timeout (default 10) after which worker threads are
1583allowed to exit. SEe C<IO::AIO::max_idle>.
1584
1352=item IO::AIO::max_outstanding $maxreqs 1585=item IO::AIO::max_outstanding $maxreqs
1586
1587Sets the maximum number of outstanding requests to C<$nreqs>. If
1588you do queue up more than this number of requests, the next call to
1589C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1590C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1591longer exceeded.
1592
1593In other words, this setting does not enforce a queue limit, but can be
1594used to make poll functions block if the limit is exceeded.
1353 1595
1354This is a very bad function to use in interactive programs because it 1596This is a very bad function to use in interactive programs because it
1355blocks, and a bad way to reduce concurrency because it is inexact: Better 1597blocks, and a bad way to reduce concurrency because it is inexact: Better
1356use an C<aio_group> together with a feed callback. 1598use an C<aio_group> together with a feed callback.
1357 1599
1358Sets the maximum number of outstanding requests to C<$nreqs>. If you 1600It's main use is in scripts without an event loop - when you want to stat
1359do queue up more than this number of requests, the next call to the 1601a lot of files, you can write somehting like this:
1360C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1361function will block until the limit is no longer exceeded.
1362 1602
1363The default value is very large, so there is no practical limit on the 1603 IO::AIO::max_outstanding 32;
1364number of outstanding requests.
1365 1604
1366You can still queue as many requests as you want. Therefore, 1605 for my $path (...) {
1367C<max_outstanding> is mainly useful in simple scripts (with low values) or 1606 aio_stat $path , ...;
1368as a stop gap to shield against fatal memory overflow (with large values). 1607 IO::AIO::poll_cb;
1608 }
1609
1610 IO::AIO::flush;
1611
1612The call to C<poll_cb> inside the loop will normally return instantly, but
1613as soon as more thna C<32> reqeusts are in-flight, it will block until
1614some requests have been handled. This keeps the loop from pushing a large
1615number of C<aio_stat> requests onto the queue.
1616
1617The default value for C<max_outstanding> is very large, so there is no
1618practical limit on the number of outstanding requests.
1369 1619
1370=back 1620=back
1371 1621
1372=head3 STATISTICAL INFORMATION 1622=head3 STATISTICAL INFORMATION
1373 1623
… …
1393Returns the number of requests currently in the pending state (executed, 1643Returns the number of requests currently in the pending state (executed,
1394but not yet processed by poll_cb). 1644but not yet processed by poll_cb).
1395 1645
1396=back 1646=back
1397 1647
1648=head3 MISCELLANEOUS FUNCTIONS
1649
1650IO::AIO implements some functions that might be useful, but are not
1651asynchronous.
1652
1653=over 4
1654
1655=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1656
1657Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1658but is blocking (this makes most sense if you know the input data is
1659likely cached already and the output filehandle is set to non-blocking
1660operations).
1661
1662Returns the number of bytes copied, or C<-1> on error.
1663
1664=item IO::AIO::fadvise $fh, $offset, $len, $advice
1665
1666Simply calls the C<posix_fadvise> function (see its
1667manpage for details). The following advice constants are
1668avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1669C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1670C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1671
1672On systems that do not implement C<posix_fadvise>, this function returns
1673ENOSYS, otherwise the return value of C<posix_fadvise>.
1674
1675=item IO::AIO::madvise $scalar, $offset, $len, $advice
1676
1677Simply calls the C<posix_madvise> function (see its
1678manpage for details). The following advice constants are
1679avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1680C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1681
1682On systems that do not implement C<posix_madvise>, this function returns
1683ENOSYS, otherwise the return value of C<posix_madvise>.
1684
1685=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1686
1687Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1688$scalar (see its manpage for details). The following protect
1689constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1690C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1691
1692On systems that do not implement C<mprotect>, this function returns
1693ENOSYS, otherwise the return value of C<mprotect>.
1694
1695=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1696
1697Memory-maps a file (or anonymous memory range) and attaches it to the
1698given C<$scalar>, which will act like a string scalar.
1699
1700The only operations allowed on the scalar are C<substr>/C<vec> that don't
1701change the string length, and most read-only operations such as copying it
1702or searching it with regexes and so on.
1703
1704Anything else is unsafe and will, at best, result in memory leaks.
1705
1706The memory map associated with the C<$scalar> is automatically removed
1707when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1708C<IO::AIO::munmap> functions are called.
1709
1710This calls the C<mmap>(2) function internally. See your system's manual
1711page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1712
1713The C<$length> must be larger than zero and smaller than the actual
1714filesize.
1715
1716C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1717C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1718
1719C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1720C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1721not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1722(which is set to C<MAP_ANON> if your system only provides this
1723constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1724C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1725C<IO::AIO::MAP_NONBLOCK>
1726
1727If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1728
1729C<$offset> is the offset from the start of the file - it generally must be
1730a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1731
1732Example:
1733
1734 use Digest::MD5;
1735 use IO::AIO;
1736
1737 open my $fh, "<verybigfile"
1738 or die "$!";
1739
1740 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1741 or die "verybigfile: $!";
1742
1743 my $fast_md5 = md5 $data;
1744
1745=item IO::AIO::munmap $scalar
1746
1747Removes a previous mmap and undefines the C<$scalar>.
1748
1749=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1750
1751Calls the C<munlock> function, undoing the effects of a previous
1752C<aio_mlock> call (see its description for details).
1753
1754=item IO::AIO::munlockall
1755
1756Calls the C<munlockall> function.
1757
1758On systems that do not implement C<munlockall>, this function returns
1759ENOSYS, otherwise the return value of C<munlockall>.
1760
1761=back
1762
1398=cut 1763=cut
1399 1764
1400min_parallel 8; 1765min_parallel 8;
1401 1766
1402END { flush } 1767END { flush }
1403 1768
14041; 17691;
1405 1770
1771=head1 EVENT LOOP INTEGRATION
1772
1773It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1774automatically into many event loops:
1775
1776 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1777 use AnyEvent::AIO;
1778
1779You can also integrate IO::AIO manually into many event loops, here are
1780some examples of how to do this:
1781
1782 # EV integration
1783 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1784
1785 # Event integration
1786 Event->io (fd => IO::AIO::poll_fileno,
1787 poll => 'r',
1788 cb => \&IO::AIO::poll_cb);
1789
1790 # Glib/Gtk2 integration
1791 add_watch Glib::IO IO::AIO::poll_fileno,
1792 in => sub { IO::AIO::poll_cb; 1 };
1793
1794 # Tk integration
1795 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1796 readable => \&IO::AIO::poll_cb);
1797
1798 # Danga::Socket integration
1799 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1800 \&IO::AIO::poll_cb);
1801
1406=head2 FORK BEHAVIOUR 1802=head2 FORK BEHAVIOUR
1407 1803
1408This module should do "the right thing" when the process using it forks: 1804Usage of pthreads in a program changes the semantics of fork
1805considerably. Specifically, only async-safe functions can be called after
1806fork. Perl doesn't know about this, so in general, you cannot call fork
1807with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1808but many other extensions and (for inexplicable reasons) perl itself often
1809is linked against pthreads, so this limitation applies.
1409 1810
1410Before the fork, IO::AIO enters a quiescent state where no requests 1811Some operating systems have extensions that allow safe use of fork, and
1411can be added in other threads and no results will be processed. After 1812this module should do "the right thing" on those, and tries on others. At
1412the fork the parent simply leaves the quiescent state and continues 1813the time of this writing (2011) only GNU/Linux supports these extensions
1413request/result processing, while the child frees the request/result queue 1814to POSIX.
1414(so that the requests started before the fork will only be handled in the
1415parent). Threads will be started on demand until the limit set in the
1416parent process has been reached again.
1417
1418In short: the parent will, after a short pause, continue as if fork had
1419not been called, while the child will act as if IO::AIO has not been used
1420yet.
1421 1815
1422=head2 MEMORY USAGE 1816=head2 MEMORY USAGE
1423 1817
1424Per-request usage: 1818Per-request usage:
1425 1819

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