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Revision 1.172 by root, Thu Jan 7 18:08:21 2010 UTC vs.
Revision 1.206 by root, Sun Jul 24 03:32:51 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 = '3.4'; 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);
206 185
207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 186 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 187 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209 min_parallel max_parallel max_idle 188 min_parallel max_parallel max_idle idle_timeout
210 nreqs nready npending nthreads 189 nreqs nready npending nthreads
211 max_poll_time max_poll_reqs 190 max_poll_time max_poll_reqs
212 sendfile fadvise); 191 sendfile fadvise madvise
192 mmap munmap munlock munlockall);
213 193
214 push @AIO_REQ, qw(aio_busy); # not exported 194 push @AIO_REQ, qw(aio_busy); # not exported
215 195
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 196 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 197
218 require XSLoader; 198 require XSLoader;
219 XSLoader::load ("IO::AIO", $VERSION); 199 XSLoader::load ("IO::AIO", $VERSION);
220} 200}
221 201
222=head1 FUNCTIONS 202=head1 FUNCTIONS
203
204=head2 QUICK OVERVIEW
205
206This section simply lists the prototypes of the most important functions
207for quick reference. See the following sections for function-by-function
208documentation.
209
210 aio_open $pathname, $flags, $mode, $callback->($fh)
211 aio_close $fh, $callback->($status)
212 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
214 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
215 aio_readahead $fh,$offset,$length, $callback->($retval)
216 aio_stat $fh_or_path, $callback->($status)
217 aio_lstat $fh, $callback->($status)
218 aio_statvfs $fh_or_path, $callback->($statvfs)
219 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
220 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
221 aio_truncate $fh_or_path, $offset, $callback->($status)
222 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_unlink $pathname, $callback->($status)
224 aio_mknod $path, $mode, $dev, $callback->($status)
225 aio_link $srcpath, $dstpath, $callback->($status)
226 aio_symlink $srcpath, $dstpath, $callback->($status)
227 aio_readlink $path, $callback->($link)
228 aio_realpath $path, $callback->($link)
229 aio_rename $srcpath, $dstpath, $callback->($status)
230 aio_mkdir $pathname, $mode, $callback->($status)
231 aio_rmdir $pathname, $callback->($status)
232 aio_readdir $pathname, $callback->($entries)
233 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
234 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
235 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
236 aio_load $path, $data, $callback->($status)
237 aio_copy $srcpath, $dstpath, $callback->($status)
238 aio_move $srcpath, $dstpath, $callback->($status)
239 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
240 aio_rmtree $path, $callback->($status)
241 aio_sync $callback->($status)
242 aio_syncfs $fh, $callback->($status)
243 aio_fsync $fh, $callback->($status)
244 aio_fdatasync $fh, $callback->($status)
245 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
246 aio_pathsync $path, $callback->($status)
247 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
248 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
249 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
250 aio_mlockall $flags, $callback->($status)
251 aio_group $callback->(...)
252 aio_nop $callback->()
253
254 $prev_pri = aioreq_pri [$pri]
255 aioreq_nice $pri_adjust
256
257 IO::AIO::poll_wait
258 IO::AIO::poll_cb
259 IO::AIO::poll
260 IO::AIO::flush
261 IO::AIO::max_poll_reqs $nreqs
262 IO::AIO::max_poll_time $seconds
263 IO::AIO::min_parallel $nthreads
264 IO::AIO::max_parallel $nthreads
265 IO::AIO::max_idle $nthreads
266 IO::AIO::idle_timeout $seconds
267 IO::AIO::max_outstanding $maxreqs
268 IO::AIO::nreqs
269 IO::AIO::nready
270 IO::AIO::npending
271
272 IO::AIO::sendfile $ofh, $ifh, $offset, $count
273 IO::AIO::fadvise $fh, $offset, $len, $advice
274 IO::AIO::madvise $scalar, $offset, $length, $advice
275 IO::AIO::mprotect $scalar, $offset, $length, $protect
276 IO::AIO::munlock $scalar, $offset = 0, $length = undef
277 IO::AIO::munlockall
223 278
224=head2 AIO REQUEST FUNCTIONS 279=head2 AIO REQUEST FUNCTIONS
225 280
226All the C<aio_*> calls are more or less thin wrappers around the syscall 281All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 282with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 362by the umask in effect then the request is being executed, so better never
308change the umask. 363change the umask.
309 364
310Example: 365Example:
311 366
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 367 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 368 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 369 print "open successful, fh is $_[0]\n";
315 ... 370 ...
316 } else { 371 } else {
317 die "open failed: $!\n"; 372 die "open failed: $!\n";
318 } 373 }
319 }; 374 };
320 375
376In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
377C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
378following POSIX and non-POSIX constants are available (missing ones on
379your system are, as usual, C<0>):
380
381C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
382C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
383C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
384
321 385
322=item aio_close $fh, $callback->($status) 386=item aio_close $fh, $callback->($status)
323 387
324Asynchronously close a file and call the callback with the result 388Asynchronously close a file and call the callback with the result
325code. 389code.
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375 439
376Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 440Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377reading at byte offset C<$in_offset>, and starts writing at the current 441reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 442file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 443than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 444other. The same C<$in_fh> works fine though, as this function does not
445move or use the file offset of C<$in_fh>.
381 446
447Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
448are written, and there is no way to find out how many more bytes have been
449read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
450number of bytes written to C<$out_fh>. Only if the result value equals
451C<$length> one can assume that C<$length> bytes have been read.
452
453Unlike with other C<aio_> functions, it makes a lot of sense to use
454C<aio_sendfile> on non-blocking sockets, as long as one end (typically
455the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
456the socket I/O will be non-blocking. Note, however, that you can run
457into a trap where C<aio_sendfile> reads some data with readahead, then
458fails to write all data, and when the socket is ready the next time, the
459data in the cache is already lost, forcing C<aio_sendfile> to again hit
460the disk. Explicit C<aio_read> + C<aio_write> let's you better control
461resource usage.
462
382This call tries to make use of a native C<sendfile> syscall to provide 463This call tries to make use of a native C<sendfile>-like syscall to
383zero-copy operation. For this to work, C<$out_fh> should refer to a 464provide zero-copy operation. For this to work, C<$out_fh> should refer to
384socket, and C<$in_fh> should refer to mmap'able file. 465a socket, and C<$in_fh> should refer to an mmap'able file.
385 466
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 467If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 468C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388it will be emulated, so you can call C<aio_sendfile> on any type of 469C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389filehandle regardless of the limitations of the operating system. 470type of filehandle regardless of the limitations of the operating system.
390 471
391Please note, however, that C<aio_sendfile> can read more bytes from 472As native sendfile syscalls (as practically any non-POSIX interface hacked
392C<$in_fh> than are written, and there is no way to find out how many 473together 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 474on many systems, this implementation tries to work around some known bugs
394provides the number of bytes written to C<$out_fh>. Only if the result 475in Linux and FreeBSD kernels (probably others, too), but that might fail,
395value equals C<$length> one can assume that C<$length> bytes have been 476so you really really should check the return value of C<aio_sendfile> -
396read. 477fewre bytes than expected might have been transferred.
397 478
398 479
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 480=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 481
401C<aio_readahead> populates the page cache with data from a file so that 482C<aio_readahead> populates the page cache with data from a file so that
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424 505
425Currently, the stats are always 64-bit-stats, i.e. instead of returning an 506Currently, 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 507error when stat'ing a large file, the results will be silently truncated
427unless perl itself is compiled with large file support. 508unless perl itself is compiled with large file support.
428 509
510To help interpret the mode and dev/rdev stat values, IO::AIO offers the
511following constants and functions (if not implemented, the constants will
512be C<0> and the functions will either C<croak> or fall back on traditional
513behaviour).
514
515C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
516C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
517C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
518
429Example: Print the length of F</etc/passwd>: 519Example: Print the length of F</etc/passwd>:
430 520
431 aio_stat "/etc/passwd", sub { 521 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 522 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 523 print "size is ", -s _, "\n";
434 }; 524 };
435 525
436 526
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 527=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 528
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 529Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 530whether a file handle or path was passed.
441 531
442On success, the callback is passed a hash reference with the following 532On success, the callback is passed a hash reference with the following
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534 624
535The only (POSIX-) portable way of calling this function is: 625The only (POSIX-) portable way of calling this function is:
536 626
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 627 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 628
629See C<aio_stat> for info about some potentially helpful extra constants
630and functions.
539 631
540=item aio_link $srcpath, $dstpath, $callback->($status) 632=item aio_link $srcpath, $dstpath, $callback->($status)
541 633
542Asynchronously create a new link to the existing object at C<$srcpath> at 634Asynchronously create a new link to the existing object at C<$srcpath> at
543the path C<$dstpath> and call the callback with the result code. 635the path C<$dstpath> and call the callback with the result code.
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554Asynchronously read the symlink specified by C<$path> and pass it to 646Asynchronously read the symlink specified by C<$path> and pass it to
555the callback. If an error occurs, nothing or undef gets passed to the 647the callback. If an error occurs, nothing or undef gets passed to the
556callback. 648callback.
557 649
558 650
651=item aio_realpath $path, $callback->($path)
652
653Asynchronously make the path absolute and resolve any symlinks in
654C<$path>. The resulting path only consists of directories (Same as
655L<Cwd::realpath>).
656
657This request can be used to get the absolute path of the current working
658directory by passing it a path of F<.> (a single dot).
659
660
559=item aio_rename $srcpath, $dstpath, $callback->($status) 661=item aio_rename $srcpath, $dstpath, $callback->($status)
560 662
561Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 663Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
562rename(2) and call the callback with the result code. 664rename(2) and call the callback with the result code.
563 665
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596 698
597=over 4 699=over 4
598 700
599=item IO::AIO::READDIR_DENTS 701=item IO::AIO::READDIR_DENTS
600 702
601When this flag is off, then the callback gets an arrayref with of names 703When this flag is off, then the callback gets an arrayref consisting of
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 704names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 705C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 706entry in more detail.
605 707
606C<$name> is the name of the entry. 708C<$name> is the name of the entry.
607 709
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620systems that do not deliver the inode information. 722systems that do not deliver the inode information.
621 723
622=item IO::AIO::READDIR_DIRS_FIRST 724=item IO::AIO::READDIR_DIRS_FIRST
623 725
624When this flag is set, then the names will be returned in an order where 726When this flag is set, then the names will be returned in an order where
625likely directories come first. This is useful when you need to quickly 727likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 728you need to quickly find directories, or you want to find all directories
627stat() each entry. 729while avoiding to stat() each entry.
628 730
629If the system returns type information in readdir, then this is used 731If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 732to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 733beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 734short names are tried first.
633 735
634=item IO::AIO::READDIR_STAT_ORDER 736=item IO::AIO::READDIR_STAT_ORDER
635 737
636When this flag is set, then the names will be returned in an order 738When this flag is set, then the names will be returned in an order
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781 if ($_[0] && $! == EXDEV) { 883 if ($_[0] && $! == EXDEV) {
782 aioreq_pri $pri; 884 aioreq_pri $pri;
783 add $grp aio_copy $src, $dst, sub { 885 add $grp aio_copy $src, $dst, sub {
784 $grp->result ($_[0]); 886 $grp->result ($_[0]);
785 887
786 if (!$_[0]) { 888 unless ($_[0]) {
787 aioreq_pri $pri; 889 aioreq_pri $pri;
788 add $grp aio_unlink $src; 890 add $grp aio_unlink $src;
789 } 891 }
790 }; 892 };
791 } else { 893 } else {
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983callback with the fdatasync result code. 1085callback with the fdatasync result code.
984 1086
985If this call isn't available because your OS lacks it or it couldn't be 1087If 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. 1088detected, it will be emulated by calling C<fsync> instead.
987 1089
1090=item aio_syncfs $fh, $callback->($status)
1091
1092Asynchronously call the syncfs syscall to sync the filesystem associated
1093to the given filehandle and call the callback with the syncfs result
1094code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1095errno to C<ENOSYS> nevertheless.
1096
988=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 1097=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
989 1098
990Sync the data portion of the file specified by C<$offset> and C<$length> 1099Sync the data portion of the file specified by C<$offset> and C<$length>
991to disk (but NOT the metadata), by calling the Linux-specific 1100to disk (but NOT the metadata), by calling the Linux-specific
992sync_file_range call. If sync_file_range is not available or it returns 1101sync_file_range call. If sync_file_range is not available or it returns
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1039} 1148}
1040 1149
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1150=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1151
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1152This 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 1153scalars (see the C<IO::AIO::mmap> function, although it also works on data
1154scalars 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 1155scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1156it).
1047 1157
1048It calls the C<msync> function of your OS, if available, with the memory 1158It 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 1159area 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> 1160later. 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 1161is C<undef>, then it goes till the end of the string. The flags can be
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1062as for C<aio_msync>, above, except for flags, which must be either 1172as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1173C<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 1174C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1175writing an octet from it, which dirties the page).
1066 1176
1177=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1178
1179This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1180scalars.
1181
1182It reads in all the pages of the underlying storage into memory (if any)
1183and locks them, so they are not getting swapped/paged out or removed.
1184
1185If C<$length> is undefined, then the scalar will be locked till the end.
1186
1187On systems that do not implement C<mlock>, this function returns C<-1>
1188and sets errno to C<ENOSYS>.
1189
1190Note that the corresponding C<munlock> is synchronous and is
1191documented under L<MISCELLANEOUS FUNCTIONS>.
1192
1193Example: open a file, mmap and mlock it - both will be undone when
1194C<$data> gets destroyed.
1195
1196 open my $fh, "<", $path or die "$path: $!";
1197 my $data;
1198 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1199 aio_mlock $data; # mlock in background
1200
1201=item aio_mlockall $flags, $callback->($status)
1202
1203Calls the C<mlockall> function with the given C<$flags> (a combination of
1204C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1205
1206On systems that do not implement C<mlockall>, this function returns C<-1>
1207and sets errno to C<ENOSYS>.
1208
1209Note that the corresponding C<munlockall> is synchronous and is
1210documented under L<MISCELLANEOUS FUNCTIONS>.
1211
1212Example: asynchronously lock all current and future pages into memory.
1213
1214 aio_mlockall IO::AIO::MCL_FUTURE;
1215
1067=item aio_group $callback->(...) 1216=item aio_group $callback->(...)
1068 1217
1069This is a very special aio request: Instead of doing something, it is a 1218This 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 1219container for other aio requests, which is useful if you want to bundle
1071many requests into a single, composite, request with a definite callback 1220many requests into a single, composite, request with a definite callback
… …
1294 1443
1295See C<poll_cb> for an example. 1444See C<poll_cb> for an example.
1296 1445
1297=item IO::AIO::poll_cb 1446=item IO::AIO::poll_cb
1298 1447
1299Process some outstanding events on the result pipe. You have to call this 1448Process 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 1449this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1450were 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 1451reason. Returns immediately when no events are outstanding. The amount of
1303C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1452events processed depends on the settings of C<IO::AIO::max_poll_req> and
1453C<IO::AIO::max_poll_time>.
1304 1454
1305If not all requests were processed for whatever reason, the filehandle 1455If 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 1456will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1457do anything special to have it called later.
1308 1458
1459Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1460ready, it can be beneficial to call this function from loops which submit
1461a lot of requests, to make sure the results get processed when they become
1462available and not just when the loop is finished and the event loop takes
1463over again. This function returns very fast when there are no outstanding
1464requests.
1465
1309Example: Install an Event watcher that automatically calls 1466Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1467IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1468SYNOPSIS section, at the top of this document):
1312 1469
1313 Event->io (fd => IO::AIO::poll_fileno, 1470 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1471 poll => 'r', async => 1,
1315 cb => \&IO::AIO::poll_cb); 1472 cb => \&IO::AIO::poll_cb);
1473
1474=item IO::AIO::poll_wait
1475
1476If there are any outstanding requests and none of them in the result
1477phase, wait till the result filehandle becomes ready for reading (simply
1478does a C<select> on the filehandle. This is useful if you want to
1479synchronously wait for some requests to finish).
1480
1481See C<nreqs> for an example.
1482
1483=item IO::AIO::poll
1484
1485Waits until some requests have been handled.
1486
1487Returns the number of requests processed, but is otherwise strictly
1488equivalent to:
1489
1490 IO::AIO::poll_wait, IO::AIO::poll_cb
1491
1492=item IO::AIO::flush
1493
1494Wait till all outstanding AIO requests have been handled.
1495
1496Strictly equivalent to:
1497
1498 IO::AIO::poll_wait, IO::AIO::poll_cb
1499 while IO::AIO::nreqs;
1316 1500
1317=item IO::AIO::max_poll_reqs $nreqs 1501=item IO::AIO::max_poll_reqs $nreqs
1318 1502
1319=item IO::AIO::max_poll_time $seconds 1503=item IO::AIO::max_poll_time $seconds
1320 1504
… …
1345 # use a low priority so other tasks have priority 1529 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1530 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1531 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1532 cb => &IO::AIO::poll_cb);
1349 1533
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 1534=back
1378 1535
1379=head3 CONTROLLING THE NUMBER OF THREADS 1536=head3 CONTROLLING THE NUMBER OF THREADS
1380 1537
1381=over 1538=over
… …
1414 1571
1415Under normal circumstances you don't need to call this function. 1572Under normal circumstances you don't need to call this function.
1416 1573
1417=item IO::AIO::max_idle $nthreads 1574=item IO::AIO::max_idle $nthreads
1418 1575
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1576Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1577(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1578timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1579C<$nthreads> other threads are also idle, it will free its resources and
1580exit.
1423 1581
1424This is useful when you allow a large number of threads (e.g. 100 or 1000) 1582This 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 1583to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1584under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1585
1428The default is probably ok in most situations, especially if thread 1586The default is probably ok in most situations, especially if thread
1429creation is fast. If thread creation is very slow on your system you might 1587creation is fast. If thread creation is very slow on your system you might
1430want to use larger values. 1588want to use larger values.
1431 1589
1590=item IO::AIO::idle_timeout $seconds
1591
1592Sets the minimum idle timeout (default 10) after which worker threads are
1593allowed to exit. SEe C<IO::AIO::max_idle>.
1594
1432=item IO::AIO::max_outstanding $maxreqs 1595=item IO::AIO::max_outstanding $maxreqs
1596
1597Sets the maximum number of outstanding requests to C<$nreqs>. If
1598you do queue up more than this number of requests, the next call to
1599C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1600C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1601longer exceeded.
1602
1603In other words, this setting does not enforce a queue limit, but can be
1604used to make poll functions block if the limit is exceeded.
1433 1605
1434This is a very bad function to use in interactive programs because it 1606This 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 1607blocks, and a bad way to reduce concurrency because it is inexact: Better
1436use an C<aio_group> together with a feed callback. 1608use an C<aio_group> together with a feed callback.
1437 1609
1438Sets the maximum number of outstanding requests to C<$nreqs>. If you 1610It'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 1611a 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 1612
1443The default value is very large, so there is no practical limit on the 1613 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1614
1446You can still queue as many requests as you want. Therefore, 1615 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1616 aio_stat $path , ...;
1448as a stop gap to shield against fatal memory overflow (with large values). 1617 IO::AIO::poll_cb;
1618 }
1619
1620 IO::AIO::flush;
1621
1622The call to C<poll_cb> inside the loop will normally return instantly, but
1623as soon as more thna C<32> reqeusts are in-flight, it will block until
1624some requests have been handled. This keeps the loop from pushing a large
1625number of C<aio_stat> requests onto the queue.
1626
1627The default value for C<max_outstanding> is very large, so there is no
1628practical limit on the number of outstanding requests.
1449 1629
1450=back 1630=back
1451 1631
1452=head3 STATISTICAL INFORMATION 1632=head3 STATISTICAL INFORMATION
1453 1633
… …
1491 1671
1492Returns the number of bytes copied, or C<-1> on error. 1672Returns the number of bytes copied, or C<-1> on error.
1493 1673
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1674=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1675
1496Simply calls the C<posix_fadvise> function (see it's 1676Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1677manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1678avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1679C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1680C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1681
1502On systems that do not implement C<posix_fadvise>, this function returns 1682On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1683ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 1684
1685=item IO::AIO::madvise $scalar, $offset, $len, $advice
1686
1687Simply calls the C<posix_madvise> function (see its
1688manpage for details). The following advice constants are
1689avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1690C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1691
1692On systems that do not implement C<posix_madvise>, this function returns
1693ENOSYS, otherwise the return value of C<posix_madvise>.
1694
1695=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1696
1697Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1698$scalar (see its manpage for details). The following protect
1699constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1700C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1701
1702On systems that do not implement C<mprotect>, this function returns
1703ENOSYS, otherwise the return value of C<mprotect>.
1704
1705=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1706
1707Memory-maps a file (or anonymous memory range) and attaches it to the
1708given C<$scalar>, which will act like a string scalar.
1709
1710The only operations allowed on the scalar are C<substr>/C<vec> that don't
1711change the string length, and most read-only operations such as copying it
1712or searching it with regexes and so on.
1713
1714Anything else is unsafe and will, at best, result in memory leaks.
1715
1716The memory map associated with the C<$scalar> is automatically removed
1717when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1718C<IO::AIO::munmap> functions are called.
1719
1720This calls the C<mmap>(2) function internally. See your system's manual
1721page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1722
1723The C<$length> must be larger than zero and smaller than the actual
1724filesize.
1725
1726C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1727C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1728
1729C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1730C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1731not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1732(which is set to C<MAP_ANON> if your system only provides this
1733constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1734C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1735C<IO::AIO::MAP_NONBLOCK>
1736
1737If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1738
1739C<$offset> is the offset from the start of the file - it generally must be
1740a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1741
1742Example:
1743
1744 use Digest::MD5;
1745 use IO::AIO;
1746
1747 open my $fh, "<verybigfile"
1748 or die "$!";
1749
1750 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1751 or die "verybigfile: $!";
1752
1753 my $fast_md5 = md5 $data;
1754
1755=item IO::AIO::munmap $scalar
1756
1757Removes a previous mmap and undefines the C<$scalar>.
1758
1759=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1760
1761Calls the C<munlock> function, undoing the effects of a previous
1762C<aio_mlock> call (see its description for details).
1763
1764=item IO::AIO::munlockall
1765
1766Calls the C<munlockall> function.
1767
1768On systems that do not implement C<munlockall>, this function returns
1769ENOSYS, otherwise the return value of C<munlockall>.
1770
1505=back 1771=back
1506 1772
1507=cut 1773=cut
1508 1774
1509min_parallel 8; 1775min_parallel 8;
1510 1776
1511END { flush } 1777END { flush }
1512 1778
15131; 17791;
1514 1780
1781=head1 EVENT LOOP INTEGRATION
1782
1783It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1784automatically into many event loops:
1785
1786 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1787 use AnyEvent::AIO;
1788
1789You can also integrate IO::AIO manually into many event loops, here are
1790some examples of how to do this:
1791
1792 # EV integration
1793 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1794
1795 # Event integration
1796 Event->io (fd => IO::AIO::poll_fileno,
1797 poll => 'r',
1798 cb => \&IO::AIO::poll_cb);
1799
1800 # Glib/Gtk2 integration
1801 add_watch Glib::IO IO::AIO::poll_fileno,
1802 in => sub { IO::AIO::poll_cb; 1 };
1803
1804 # Tk integration
1805 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1806 readable => \&IO::AIO::poll_cb);
1807
1808 # Danga::Socket integration
1809 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1810 \&IO::AIO::poll_cb);
1811
1515=head2 FORK BEHAVIOUR 1812=head2 FORK BEHAVIOUR
1516 1813
1517This module should do "the right thing" when the process using it forks: 1814Usage of pthreads in a program changes the semantics of fork
1815considerably. Specifically, only async-safe functions can be called after
1816fork. Perl doesn't know about this, so in general, you cannot call fork
1817with defined behaviour in perl if pthreads are involved. IO::AIO uses
1818pthreads, so this applies, but many other extensions and (for inexplicable
1819reasons) perl itself often is linked against pthreads, so this limitation
1820applies to quite a lot of perls.
1518 1821
1519Before the fork, IO::AIO enters a quiescent state where no requests 1822This 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 1823only works in the process that loaded it. Forking is fully supported, but
1521the fork the parent simply leaves the quiescent state and continues 1824using 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 1825
1527In short: the parent will, after a short pause, continue as if fork had 1826You 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 1827forking. You could also try to call the L<IO::AIO::reinit> function in the
1529yet. 1828child:
1829
1830=over 4
1831
1832=item IO::AIO::reinit
1833
1834Abondons all current requests and I/O threads and simply reinitialises all
1835data structures. This is not an operation suppported by any standards, but
1836happens to work on GNU/Linux and some newer BSD systems.
1837
1838The only reasonable use for this function is to call it after forking, if
1839C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
1840the process will result in undefined behaviour. Calling it at any time
1841will also result in any undefined (by POSIX) behaviour.
1842
1843=back
1530 1844
1531=head2 MEMORY USAGE 1845=head2 MEMORY USAGE
1532 1846
1533Per-request usage: 1847Per-request usage:
1534 1848

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