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Revision 1.173 by root, Thu Jan 7 20:25:57 2010 UTC vs.
Revision 1.208 by root, Mon Sep 26 20:19:08 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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25 my $req = aio_unlink "/tmp/file", sub { }; 25 my $req = aio_unlink "/tmp/file", sub { };
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
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $aio_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 30
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. It is implemented as an interface to C<libeio> 34operating system supports. It is implemented as an interface to C<libeio>
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99 76
100 # register the IO::AIO callback with EV 77 # register the IO::AIO callback with EV
101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 79
103 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105 my $fh = shift 82 my $fh = shift
106 or die "error while opening: $!"; 83 or die "error while opening: $!";
107 84
108 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh; 86 my $size = -s $fh;
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191use common::sense; 168use common::sense;
192 169
193use base 'Exporter'; 170use base 'Exporter';
194 171
195BEGIN { 172BEGIN {
196 our $VERSION = '3.5'; 173 our $VERSION = '4.0';
197 174
198 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
199 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
200 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
201 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
179 aio_pathsync aio_readahead
202 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
203 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
204 aio_chmod aio_utime aio_truncate 182 aio_chmod aio_utime aio_truncate
205 aio_msync aio_mtouch aio_statvfs); 183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs
185 aio_wd);
206 186
207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
210 nreqs nready npending nthreads 190 nreqs nready npending nthreads
211 max_poll_time max_poll_reqs 191 max_poll_time max_poll_reqs
212 sendfile fadvise); 192 sendfile fadvise madvise
193 mmap munmap munlock munlockall);
213 194
214 push @AIO_REQ, qw(aio_busy); # not exported 195 push @AIO_REQ, qw(aio_busy); # not exported
215 196
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 198
218 require XSLoader; 199 require XSLoader;
219 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
220} 201}
221 202
222=head1 FUNCTIONS 203=head1 FUNCTIONS
204
205=head2 QUICK OVERVIEW
206
207This section simply lists the prototypes of the most important functions
208for quick reference. See the following sections for function-by-function
209documentation.
210
211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_unlink $pathname, $callback->($status)
226 aio_mknod $path, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $path, $callback->($link)
230 aio_realpath $path, $callback->($link)
231 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
238 aio_load $path, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $path, $callback->($status)
243 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $path, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...)
254 aio_nop $callback->()
255
256 $prev_pri = aioreq_pri [$pri]
257 aioreq_nice $pri_adjust
258
259 IO::AIO::poll_wait
260 IO::AIO::poll_cb
261 IO::AIO::poll
262 IO::AIO::flush
263 IO::AIO::max_poll_reqs $nreqs
264 IO::AIO::max_poll_time $seconds
265 IO::AIO::min_parallel $nthreads
266 IO::AIO::max_parallel $nthreads
267 IO::AIO::max_idle $nthreads
268 IO::AIO::idle_timeout $seconds
269 IO::AIO::max_outstanding $maxreqs
270 IO::AIO::nreqs
271 IO::AIO::nready
272 IO::AIO::npending
273
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice
276 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall
223 280
224=head2 AIO REQUEST FUNCTIONS 281=head2 AIO REQUEST FUNCTIONS
225 282
226All the C<aio_*> calls are more or less thin wrappers around the syscall 283All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 284with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 364by the umask in effect then the request is being executed, so better never
308change the umask. 365change the umask.
309 366
310Example: 367Example:
311 368
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 369 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 370 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 371 print "open successful, fh is $_[0]\n";
315 ... 372 ...
316 } else { 373 } else {
317 die "open failed: $!\n"; 374 die "open failed: $!\n";
318 } 375 }
319 }; 376 };
320 377
378In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
379C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
380following POSIX and non-POSIX constants are available (missing ones on
381your system are, as usual, C<0>):
382
383C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
384C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
385C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
386
321 387
322=item aio_close $fh, $callback->($status) 388=item aio_close $fh, $callback->($status)
323 389
324Asynchronously close a file and call the callback with the result 390Asynchronously close a file and call the callback with the result
325code. 391code.
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375 441
376Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 442Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377reading at byte offset C<$in_offset>, and starts writing at the current 443reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 444file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 445than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 446other. The same C<$in_fh> works fine though, as this function does not
447move or use the file offset of C<$in_fh>.
381 448
449Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
450are written, and there is no way to find out how many more bytes have been
451read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
452number of bytes written to C<$out_fh>. Only if the result value equals
453C<$length> one can assume that C<$length> bytes have been read.
454
455Unlike with other C<aio_> functions, it makes a lot of sense to use
456C<aio_sendfile> on non-blocking sockets, as long as one end (typically
457the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
458the socket I/O will be non-blocking. Note, however, that you can run
459into a trap where C<aio_sendfile> reads some data with readahead, then
460fails to write all data, and when the socket is ready the next time, the
461data in the cache is already lost, forcing C<aio_sendfile> to again hit
462the disk. Explicit C<aio_read> + C<aio_write> let's you better control
463resource usage.
464
382This call tries to make use of a native C<sendfile> syscall to provide 465This call tries to make use of a native C<sendfile>-like syscall to
383zero-copy operation. For this to work, C<$out_fh> should refer to a 466provide zero-copy operation. For this to work, C<$out_fh> should refer to
384socket, and C<$in_fh> should refer to mmap'able file. 467a socket, and C<$in_fh> should refer to an mmap'able file.
385 468
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 469If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 470C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388it will be emulated, so you can call C<aio_sendfile> on any type of 471C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389filehandle regardless of the limitations of the operating system. 472type of filehandle regardless of the limitations of the operating system.
390 473
391Please note, however, that C<aio_sendfile> can read more bytes from 474As native sendfile syscalls (as practically any non-POSIX interface hacked
392C<$in_fh> than are written, and there is no way to find out how many 475together in a hurry to improve benchmark numbers) tend to be rather buggy
393bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 476on many systems, this implementation tries to work around some known bugs
394provides the number of bytes written to C<$out_fh>. Only if the result 477in Linux and FreeBSD kernels (probably others, too), but that might fail,
395value equals C<$length> one can assume that C<$length> bytes have been 478so you really really should check the return value of C<aio_sendfile> -
396read. 479fewre bytes than expected might have been transferred.
397 480
398 481
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 482=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 483
401C<aio_readahead> populates the page cache with data from a file so that 484C<aio_readahead> populates the page cache with data from a file so that
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424 507
425Currently, the stats are always 64-bit-stats, i.e. instead of returning an 508Currently, the stats are always 64-bit-stats, i.e. instead of returning an
426error when stat'ing a large file, the results will be silently truncated 509error when stat'ing a large file, the results will be silently truncated
427unless perl itself is compiled with large file support. 510unless perl itself is compiled with large file support.
428 511
512To help interpret the mode and dev/rdev stat values, IO::AIO offers the
513following constants and functions (if not implemented, the constants will
514be C<0> and the functions will either C<croak> or fall back on traditional
515behaviour).
516
517C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
518C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
519C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
520
429Example: Print the length of F</etc/passwd>: 521Example: Print the length of F</etc/passwd>:
430 522
431 aio_stat "/etc/passwd", sub { 523 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 524 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 525 print "size is ", -s _, "\n";
434 }; 526 };
435 527
436 528
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 529=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 530
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 531Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 532whether a file handle or path was passed.
441 533
442On success, the callback is passed a hash reference with the following 534On success, the callback is passed a hash reference with the following
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534 626
535The only (POSIX-) portable way of calling this function is: 627The only (POSIX-) portable way of calling this function is:
536 628
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 629 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 630
631See C<aio_stat> for info about some potentially helpful extra constants
632and functions.
539 633
540=item aio_link $srcpath, $dstpath, $callback->($status) 634=item aio_link $srcpath, $dstpath, $callback->($status)
541 635
542Asynchronously create a new link to the existing object at C<$srcpath> at 636Asynchronously create a new link to the existing object at C<$srcpath> at
543the path C<$dstpath> and call the callback with the result code. 637the path C<$dstpath> and call the callback with the result code.
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554Asynchronously read the symlink specified by C<$path> and pass it to 648Asynchronously read the symlink specified by C<$path> and pass it to
555the callback. If an error occurs, nothing or undef gets passed to the 649the callback. If an error occurs, nothing or undef gets passed to the
556callback. 650callback.
557 651
558 652
653=item aio_realpath $path, $callback->($path)
654
655Asynchronously make the path absolute and resolve any symlinks in
656C<$path>. The resulting path only consists of directories (Same as
657L<Cwd::realpath>).
658
659This request can be used to get the absolute path of the current working
660directory by passing it a path of F<.> (a single dot).
661
662
559=item aio_rename $srcpath, $dstpath, $callback->($status) 663=item aio_rename $srcpath, $dstpath, $callback->($status)
560 664
561Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 665Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
562rename(2) and call the callback with the result code. 666rename(2) and call the callback with the result code.
563 667
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585array-ref with the filenames. 689array-ref with the filenames.
586 690
587 691
588=item aio_readdirx $pathname, $flags, $callback->($entries, $flags) 692=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
589 693
590Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune 694Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
591behaviour and output format. In case of an error, C<$entries> will be 695tune behaviour and output format. In case of an error, C<$entries> will be
592C<undef>. 696C<undef>.
593 697
594The flags are a combination of the following constants, ORed together (the 698The flags are a combination of the following constants, ORed together (the
595flags will also be passed to the callback, possibly modified): 699flags will also be passed to the callback, possibly modified):
596 700
597=over 4 701=over 4
598 702
599=item IO::AIO::READDIR_DENTS 703=item IO::AIO::READDIR_DENTS
600 704
601When this flag is off, then the callback gets an arrayref with of names 705When this flag is off, then the callback gets an arrayref consisting of
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 706names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 707C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 708entry in more detail.
605 709
606C<$name> is the name of the entry. 710C<$name> is the name of the entry.
607 711
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620systems that do not deliver the inode information. 724systems that do not deliver the inode information.
621 725
622=item IO::AIO::READDIR_DIRS_FIRST 726=item IO::AIO::READDIR_DIRS_FIRST
623 727
624When this flag is set, then the names will be returned in an order where 728When this flag is set, then the names will be returned in an order where
625likely directories come first. This is useful when you need to quickly 729likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 730you need to quickly find directories, or you want to find all directories
627stat() each entry. 731while avoiding to stat() each entry.
628 732
629If the system returns type information in readdir, then this is used 733If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 734to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 735beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 736short names are tried first.
633 737
634=item IO::AIO::READDIR_STAT_ORDER 738=item IO::AIO::READDIR_STAT_ORDER
635 739
636When this flag is set, then the names will be returned in an order 740When this flag is set, then the names will be returned in an order
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643 747
644=item IO::AIO::READDIR_FOUND_UNKNOWN 748=item IO::AIO::READDIR_FOUND_UNKNOWN
645 749
646This flag should not be set when calling C<aio_readdirx>. Instead, it 750This flag should not be set when calling C<aio_readdirx>. Instead, it
647is being set by C<aio_readdirx>, when any of the C<$type>'s found were 751is being set by C<aio_readdirx>, when any of the C<$type>'s found were
648C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 752C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
649C<$type>'s are known, which can be used to speed up some algorithms. 753C<$type>'s are known, which can be used to speed up some algorithms.
650 754
651=back 755=back
652 756
653 757
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781 if ($_[0] && $! == EXDEV) { 885 if ($_[0] && $! == EXDEV) {
782 aioreq_pri $pri; 886 aioreq_pri $pri;
783 add $grp aio_copy $src, $dst, sub { 887 add $grp aio_copy $src, $dst, sub {
784 $grp->result ($_[0]); 888 $grp->result ($_[0]);
785 889
786 if (!$_[0]) { 890 unless ($_[0]) {
787 aioreq_pri $pri; 891 aioreq_pri $pri;
788 add $grp aio_unlink $src; 892 add $grp aio_unlink $src;
789 } 893 }
790 }; 894 };
791 } else { 895 } else {
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835Then entries will be sorted into likely directories a non-initial dot 939Then entries will be sorted into likely directories a non-initial dot
836currently) and likely non-directories (see C<aio_readdirx>). Then every 940currently) and likely non-directories (see C<aio_readdirx>). Then every
837entry plus an appended C</.> will be C<stat>'ed, likely directories first, 941entry plus an appended C</.> will be C<stat>'ed, likely directories first,
838in order of their inode numbers. If that succeeds, it assumes that the 942in order of their inode numbers. If that succeeds, it assumes that the
839entry is a directory or a symlink to directory (which will be checked 943entry is a directory or a symlink to directory (which will be checked
840seperately). This is often faster than stat'ing the entry itself because 944separately). This is often faster than stat'ing the entry itself because
841filesystems might detect the type of the entry without reading the inode 945filesystems might detect the type of the entry without reading the inode
842data (e.g. ext2fs filetype feature), even on systems that cannot return 946data (e.g. ext2fs filetype feature), even on systems that cannot return
843the filetype information on readdir. 947the filetype information on readdir.
844 948
845If the known number of directories (link count - 2) has been reached, the 949If the known number of directories (link count - 2) has been reached, the
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983callback with the fdatasync result code. 1087callback with the fdatasync result code.
984 1088
985If this call isn't available because your OS lacks it or it couldn't be 1089If this call isn't available because your OS lacks it or it couldn't be
986detected, it will be emulated by calling C<fsync> instead. 1090detected, it will be emulated by calling C<fsync> instead.
987 1091
1092=item aio_syncfs $fh, $callback->($status)
1093
1094Asynchronously call the syncfs syscall to sync the filesystem associated
1095to the given filehandle and call the callback with the syncfs result
1096code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1097errno to C<ENOSYS> nevertheless.
1098
988=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 1099=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
989 1100
990Sync the data portion of the file specified by C<$offset> and C<$length> 1101Sync the data portion of the file specified by C<$offset> and C<$length>
991to disk (but NOT the metadata), by calling the Linux-specific 1102to disk (but NOT the metadata), by calling the Linux-specific
992sync_file_range call. If sync_file_range is not available or it returns 1103sync_file_range call. If sync_file_range is not available or it returns
… …
1039} 1150}
1040 1151
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1152=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1153
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1154This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1044scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note 1155scalars (see the C<IO::AIO::mmap> function, although it also works on data
1156scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1045that the scalar must only be modified in-place while an aio operation is 1157scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1158it).
1047 1159
1048It calls the C<msync> function of your OS, if available, with the memory 1160It calls the C<msync> function of your OS, if available, with the memory
1049area starting at C<$offset> in the string and ending C<$length> bytes 1161area starting at C<$offset> in the string and ending C<$length> bytes
1050later. If C<$length> is negative, counts from the end, and if C<$length> 1162later. If C<$length> is negative, counts from the end, and if C<$length>
1051is C<undef>, then it goes till the end of the string. The flags can be 1163is C<undef>, then it goes till the end of the string. The flags can be
… …
1062as for C<aio_msync>, above, except for flags, which must be either 1174as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1175C<0> (which reads all pages and ensures they are instantiated) or
1064C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1176C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1177writing an octet from it, which dirties the page).
1066 1178
1179=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1180
1181This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1182scalars.
1183
1184It reads in all the pages of the underlying storage into memory (if any)
1185and locks them, so they are not getting swapped/paged out or removed.
1186
1187If C<$length> is undefined, then the scalar will be locked till the end.
1188
1189On systems that do not implement C<mlock>, this function returns C<-1>
1190and sets errno to C<ENOSYS>.
1191
1192Note that the corresponding C<munlock> is synchronous and is
1193documented under L<MISCELLANEOUS FUNCTIONS>.
1194
1195Example: open a file, mmap and mlock it - both will be undone when
1196C<$data> gets destroyed.
1197
1198 open my $fh, "<", $path or die "$path: $!";
1199 my $data;
1200 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1201 aio_mlock $data; # mlock in background
1202
1203=item aio_mlockall $flags, $callback->($status)
1204
1205Calls the C<mlockall> function with the given C<$flags> (a combination of
1206C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1207
1208On systems that do not implement C<mlockall>, this function returns C<-1>
1209and sets errno to C<ENOSYS>.
1210
1211Note that the corresponding C<munlockall> is synchronous and is
1212documented under L<MISCELLANEOUS FUNCTIONS>.
1213
1214Example: asynchronously lock all current and future pages into memory.
1215
1216 aio_mlockall IO::AIO::MCL_FUTURE;
1217
1067=item aio_group $callback->(...) 1218=item aio_group $callback->(...)
1068 1219
1069This is a very special aio request: Instead of doing something, it is a 1220This is a very special aio request: Instead of doing something, it is a
1070container for other aio requests, which is useful if you want to bundle 1221container for other aio requests, which is useful if you want to bundle
1071many requests into a single, composite, request with a definite callback 1222many requests into a single, composite, request with a definite callback
… …
1294 1445
1295See C<poll_cb> for an example. 1446See C<poll_cb> for an example.
1296 1447
1297=item IO::AIO::poll_cb 1448=item IO::AIO::poll_cb
1298 1449
1299Process some outstanding events on the result pipe. You have to call this 1450Process some outstanding events on the result pipe. You have to call
1300regularly. Returns C<0> if all events could be processed, or C<-1> if it 1451this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1452were no events to process), or C<-1> if it returned earlier for whatever
1302are outstanding. The amount of events processed depends on the settings of 1453reason. Returns immediately when no events are outstanding. The amount of
1303C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1454events processed depends on the settings of C<IO::AIO::max_poll_req> and
1455C<IO::AIO::max_poll_time>.
1304 1456
1305If not all requests were processed for whatever reason, the filehandle 1457If not all requests were processed for whatever reason, the filehandle
1306will still be ready when C<poll_cb> returns, so normally you don't have to 1458will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1459do anything special to have it called later.
1308 1460
1461Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1462ready, it can be beneficial to call this function from loops which submit
1463a lot of requests, to make sure the results get processed when they become
1464available and not just when the loop is finished and the event loop takes
1465over again. This function returns very fast when there are no outstanding
1466requests.
1467
1309Example: Install an Event watcher that automatically calls 1468Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1469IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1470SYNOPSIS section, at the top of this document):
1312 1471
1313 Event->io (fd => IO::AIO::poll_fileno, 1472 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1473 poll => 'r', async => 1,
1315 cb => \&IO::AIO::poll_cb); 1474 cb => \&IO::AIO::poll_cb);
1475
1476=item IO::AIO::poll_wait
1477
1478If there are any outstanding requests and none of them in the result
1479phase, wait till the result filehandle becomes ready for reading (simply
1480does a C<select> on the filehandle. This is useful if you want to
1481synchronously wait for some requests to finish).
1482
1483See C<nreqs> for an example.
1484
1485=item IO::AIO::poll
1486
1487Waits until some requests have been handled.
1488
1489Returns the number of requests processed, but is otherwise strictly
1490equivalent to:
1491
1492 IO::AIO::poll_wait, IO::AIO::poll_cb
1493
1494=item IO::AIO::flush
1495
1496Wait till all outstanding AIO requests have been handled.
1497
1498Strictly equivalent to:
1499
1500 IO::AIO::poll_wait, IO::AIO::poll_cb
1501 while IO::AIO::nreqs;
1316 1502
1317=item IO::AIO::max_poll_reqs $nreqs 1503=item IO::AIO::max_poll_reqs $nreqs
1318 1504
1319=item IO::AIO::max_poll_time $seconds 1505=item IO::AIO::max_poll_time $seconds
1320 1506
… …
1345 # use a low priority so other tasks have priority 1531 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1532 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1533 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1534 cb => &IO::AIO::poll_cb);
1349 1535
1350=item IO::AIO::poll_wait
1351
1352If there are any outstanding requests and none of them in the result
1353phase, wait till the result filehandle becomes ready for reading (simply
1354does a C<select> on the filehandle. This is useful if you want to
1355synchronously wait for some requests to finish).
1356
1357See C<nreqs> for an example.
1358
1359=item IO::AIO::poll
1360
1361Waits until some requests have been handled.
1362
1363Returns the number of requests processed, but is otherwise strictly
1364equivalent to:
1365
1366 IO::AIO::poll_wait, IO::AIO::poll_cb
1367
1368=item IO::AIO::flush
1369
1370Wait till all outstanding AIO requests have been handled.
1371
1372Strictly equivalent to:
1373
1374 IO::AIO::poll_wait, IO::AIO::poll_cb
1375 while IO::AIO::nreqs;
1376
1377=back 1536=back
1378 1537
1379=head3 CONTROLLING THE NUMBER OF THREADS 1538=head3 CONTROLLING THE NUMBER OF THREADS
1380 1539
1381=over 1540=over
… …
1414 1573
1415Under normal circumstances you don't need to call this function. 1574Under normal circumstances you don't need to call this function.
1416 1575
1417=item IO::AIO::max_idle $nthreads 1576=item IO::AIO::max_idle $nthreads
1418 1577
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1578Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1579(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1580timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1581C<$nthreads> other threads are also idle, it will free its resources and
1582exit.
1423 1583
1424This is useful when you allow a large number of threads (e.g. 100 or 1000) 1584This is useful when you allow a large number of threads (e.g. 100 or 1000)
1425to allow for extremely high load situations, but want to free resources 1585to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1586under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1587
1428The default is probably ok in most situations, especially if thread 1588The default is probably ok in most situations, especially if thread
1429creation is fast. If thread creation is very slow on your system you might 1589creation is fast. If thread creation is very slow on your system you might
1430want to use larger values. 1590want to use larger values.
1431 1591
1592=item IO::AIO::idle_timeout $seconds
1593
1594Sets the minimum idle timeout (default 10) after which worker threads are
1595allowed to exit. SEe C<IO::AIO::max_idle>.
1596
1432=item IO::AIO::max_outstanding $maxreqs 1597=item IO::AIO::max_outstanding $maxreqs
1598
1599Sets the maximum number of outstanding requests to C<$nreqs>. If
1600you do queue up more than this number of requests, the next call to
1601C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1602C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1603longer exceeded.
1604
1605In other words, this setting does not enforce a queue limit, but can be
1606used to make poll functions block if the limit is exceeded.
1433 1607
1434This is a very bad function to use in interactive programs because it 1608This is a very bad function to use in interactive programs because it
1435blocks, and a bad way to reduce concurrency because it is inexact: Better 1609blocks, and a bad way to reduce concurrency because it is inexact: Better
1436use an C<aio_group> together with a feed callback. 1610use an C<aio_group> together with a feed callback.
1437 1611
1438Sets the maximum number of outstanding requests to C<$nreqs>. If you 1612It's main use is in scripts without an event loop - when you want to stat
1439do queue up more than this number of requests, the next call to the 1613a lot of files, you can write somehting like this:
1440C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1441function will block until the limit is no longer exceeded.
1442 1614
1443The default value is very large, so there is no practical limit on the 1615 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1616
1446You can still queue as many requests as you want. Therefore, 1617 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1618 aio_stat $path , ...;
1448as a stop gap to shield against fatal memory overflow (with large values). 1619 IO::AIO::poll_cb;
1620 }
1621
1622 IO::AIO::flush;
1623
1624The call to C<poll_cb> inside the loop will normally return instantly, but
1625as soon as more thna C<32> reqeusts are in-flight, it will block until
1626some requests have been handled. This keeps the loop from pushing a large
1627number of C<aio_stat> requests onto the queue.
1628
1629The default value for C<max_outstanding> is very large, so there is no
1630practical limit on the number of outstanding requests.
1449 1631
1450=back 1632=back
1451 1633
1452=head3 STATISTICAL INFORMATION 1634=head3 STATISTICAL INFORMATION
1453 1635
… …
1491 1673
1492Returns the number of bytes copied, or C<-1> on error. 1674Returns the number of bytes copied, or C<-1> on error.
1493 1675
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1676=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1677
1496Simply calls the C<posix_fadvise> function (see it's 1678Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1679manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1680available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1681C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1682C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1683
1502On systems that do not implement C<posix_fadvise>, this function returns 1684On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1685ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 1686
1687=item IO::AIO::madvise $scalar, $offset, $len, $advice
1688
1689Simply calls the C<posix_madvise> function (see its
1690manpage for details). The following advice constants are
1691available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1692C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1693
1694On systems that do not implement C<posix_madvise>, this function returns
1695ENOSYS, otherwise the return value of C<posix_madvise>.
1696
1697=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1698
1699Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1700$scalar (see its manpage for details). The following protect
1701constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1702C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1703
1704On systems that do not implement C<mprotect>, this function returns
1705ENOSYS, otherwise the return value of C<mprotect>.
1706
1707=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708
1709Memory-maps a file (or anonymous memory range) and attaches it to the
1710given C<$scalar>, which will act like a string scalar.
1711
1712The only operations allowed on the scalar are C<substr>/C<vec> that don't
1713change the string length, and most read-only operations such as copying it
1714or searching it with regexes and so on.
1715
1716Anything else is unsafe and will, at best, result in memory leaks.
1717
1718The memory map associated with the C<$scalar> is automatically removed
1719when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1720C<IO::AIO::munmap> functions are called.
1721
1722This calls the C<mmap>(2) function internally. See your system's manual
1723page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1724
1725The C<$length> must be larger than zero and smaller than the actual
1726filesize.
1727
1728C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1729C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1730
1731C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1732C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1733not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1734(which is set to C<MAP_ANON> if your system only provides this
1735constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1736C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1737C<IO::AIO::MAP_NONBLOCK>
1738
1739If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1740
1741C<$offset> is the offset from the start of the file - it generally must be
1742a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1743
1744Example:
1745
1746 use Digest::MD5;
1747 use IO::AIO;
1748
1749 open my $fh, "<verybigfile"
1750 or die "$!";
1751
1752 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1753 or die "verybigfile: $!";
1754
1755 my $fast_md5 = md5 $data;
1756
1757=item IO::AIO::munmap $scalar
1758
1759Removes a previous mmap and undefines the C<$scalar>.
1760
1761=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1762
1763Calls the C<munlock> function, undoing the effects of a previous
1764C<aio_mlock> call (see its description for details).
1765
1766=item IO::AIO::munlockall
1767
1768Calls the C<munlockall> function.
1769
1770On systems that do not implement C<munlockall>, this function returns
1771ENOSYS, otherwise the return value of C<munlockall>.
1772
1505=back 1773=back
1506 1774
1507=cut 1775=cut
1508 1776
1509min_parallel 8; 1777min_parallel 8;
1510 1778
1511END { flush } 1779END { flush }
1512 1780
15131; 17811;
1514 1782
1783=head1 EVENT LOOP INTEGRATION
1784
1785It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1786automatically into many event loops:
1787
1788 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1789 use AnyEvent::AIO;
1790
1791You can also integrate IO::AIO manually into many event loops, here are
1792some examples of how to do this:
1793
1794 # EV integration
1795 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1796
1797 # Event integration
1798 Event->io (fd => IO::AIO::poll_fileno,
1799 poll => 'r',
1800 cb => \&IO::AIO::poll_cb);
1801
1802 # Glib/Gtk2 integration
1803 add_watch Glib::IO IO::AIO::poll_fileno,
1804 in => sub { IO::AIO::poll_cb; 1 };
1805
1806 # Tk integration
1807 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1808 readable => \&IO::AIO::poll_cb);
1809
1810 # Danga::Socket integration
1811 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1812 \&IO::AIO::poll_cb);
1813
1515=head2 FORK BEHAVIOUR 1814=head2 FORK BEHAVIOUR
1516 1815
1517This module should do "the right thing" when the process using it forks: 1816Usage of pthreads in a program changes the semantics of fork
1817considerably. Specifically, only async-safe functions can be called after
1818fork. Perl doesn't know about this, so in general, you cannot call fork
1819with defined behaviour in perl if pthreads are involved. IO::AIO uses
1820pthreads, so this applies, but many other extensions and (for inexplicable
1821reasons) perl itself often is linked against pthreads, so this limitation
1822applies to quite a lot of perls.
1518 1823
1519Before the fork, IO::AIO enters a quiescent state where no requests 1824This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1520can be added in other threads and no results will be processed. After 1825only works in the process that loaded it. Forking is fully supported, but
1521the fork the parent simply leaves the quiescent state and continues 1826using IO::AIO in the child is not.
1522request/result processing, while the child frees the request/result queue
1523(so that the requests started before the fork will only be handled in the
1524parent). Threads will be started on demand until the limit set in the
1525parent process has been reached again.
1526 1827
1527In short: the parent will, after a short pause, continue as if fork had 1828You might get around by not I<using> IO::AIO before (or after)
1528not been called, while the child will act as if IO::AIO has not been used 1829forking. You could also try to call the L<IO::AIO::reinit> function in the
1529yet. 1830child:
1831
1832=over 4
1833
1834=item IO::AIO::reinit
1835
1836Abandons all current requests and I/O threads and simply reinitialises all
1837data structures. This is not an operation supported by any standards, but
1838happens to work on GNU/Linux and some newer BSD systems.
1839
1840The only reasonable use for this function is to call it after forking, if
1841C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
1842the process will result in undefined behaviour. Calling it at any time
1843will also result in any undefined (by POSIX) behaviour.
1844
1845=back
1530 1846
1531=head2 MEMORY USAGE 1847=head2 MEMORY USAGE
1532 1848
1533Per-request usage: 1849Per-request usage:
1534 1850

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