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Revision 1.172 by root, Thu Jan 7 18:08:21 2010 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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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 = '3.93';
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 aio_fsync
201 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
202 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
203 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
204 aio_chmod aio_utime aio_truncate 181 aio_chmod aio_utime aio_truncate
205 aio_msync aio_mtouch aio_statvfs); 182 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs);
206 184
207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209 min_parallel max_parallel max_idle 187 min_parallel max_parallel max_idle idle_timeout
210 nreqs nready npending nthreads 188 nreqs nready npending nthreads
211 max_poll_time max_poll_reqs 189 max_poll_time max_poll_reqs
212 sendfile fadvise); 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<$in_fh> should refer to an mmap'able file.
385 464
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 465If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 466C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388it will be emulated, so you can call C<aio_sendfile> on any type of 467C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389filehandle regardless of the limitations of the operating system. 468type of filehandle regardless of the limitations of the operating system.
390 469
391Please note, however, that C<aio_sendfile> can read more bytes from 470As native sendfile syscalls (as practically any non-POSIX interface hacked
392C<$in_fh> than are written, and there is no way to find out how many 471together 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 472on many systems, this implementation tries to work around some known bugs
394provides the number of bytes written to C<$out_fh>. Only if the result 473in Linux and FreeBSD kernels (probably others, too), but that might fail,
395value equals C<$length> one can assume that C<$length> bytes have been 474so you really really should check the return value of C<aio_sendfile> -
396read. 475fewre bytes than expected might have been transferred.
397 476
398 477
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 478=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 479
401C<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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424 503
425Currently, 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
426error 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
427unless perl itself is compiled with large file support. 506unless perl itself is compiled with large file support.
428 507
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
429Example: Print the length of F</etc/passwd>: 517Example: Print the length of F</etc/passwd>:
430 518
431 aio_stat "/etc/passwd", sub { 519 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 520 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 521 print "size is ", -s _, "\n";
434 }; 522 };
435 523
436 524
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 525=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 526
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 527Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 528whether a file handle or path was passed.
441 529
442On success, the callback is passed a hash reference with the following 530On success, the callback is passed a hash reference with the following
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534 622
535The only (POSIX-) portable way of calling this function is: 623The only (POSIX-) portable way of calling this function is:
536 624
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 625 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 626
627See C<aio_stat> for info about some potentially helpful extra constants
628and functions.
539 629
540=item aio_link $srcpath, $dstpath, $callback->($status) 630=item aio_link $srcpath, $dstpath, $callback->($status)
541 631
542Asynchronously 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
543the 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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554Asynchronously read the symlink specified by C<$path> and pass it to 644Asynchronously read the symlink specified by C<$path> and pass it to
555the 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
556callback. 646callback.
557 647
558 648
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
559=item aio_rename $srcpath, $dstpath, $callback->($status) 658=item aio_rename $srcpath, $dstpath, $callback->($status)
560 659
561Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 660Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
562rename(2) and call the callback with the result code. 661rename(2) and call the callback with the result code.
563 662
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596 695
597=over 4 696=over 4
598 697
599=item IO::AIO::READDIR_DENTS 698=item IO::AIO::READDIR_DENTS
600 699
601When 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
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 701names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 702C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 703entry in more detail.
605 704
606C<$name> is the name of the entry. 705C<$name> is the name of the entry.
607 706
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620systems that do not deliver the inode information. 719systems that do not deliver the inode information.
621 720
622=item IO::AIO::READDIR_DIRS_FIRST 721=item IO::AIO::READDIR_DIRS_FIRST
623 722
624When this flag is set, then the names will be returned in an order where 723When this flag is set, then the names will be returned in an order where
625likely directories come first. This is useful when you need to quickly 724likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 725you need to quickly find directories, or you want to find all directories
627stat() each entry. 726while avoiding to stat() each entry.
628 727
629If the system returns type information in readdir, then this is used 728If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 729to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 730beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 731short names are tried first.
633 732
634=item IO::AIO::READDIR_STAT_ORDER 733=item IO::AIO::READDIR_STAT_ORDER
635 734
636When this flag is set, then the names will be returned in an order 735When this flag is set, then the names will be returned in an order
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781 if ($_[0] && $! == EXDEV) { 880 if ($_[0] && $! == EXDEV) {
782 aioreq_pri $pri; 881 aioreq_pri $pri;
783 add $grp aio_copy $src, $dst, sub { 882 add $grp aio_copy $src, $dst, sub {
784 $grp->result ($_[0]); 883 $grp->result ($_[0]);
785 884
786 if (!$_[0]) { 885 unless ($_[0]) {
787 aioreq_pri $pri; 886 aioreq_pri $pri;
788 add $grp aio_unlink $src; 887 add $grp aio_unlink $src;
789 } 888 }
790 }; 889 };
791 } else { 890 } else {
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1039} 1138}
1040 1139
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1140=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1141
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1142This 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 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
1045that the scalar must only be modified in-place while an aio operation is 1145scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1146it).
1047 1147
1048It calls the C<msync> function of your OS, if available, with the memory 1148It 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 1149area 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> 1150later. 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 1151is 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 1162as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1163C<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 1164C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1165writing an octet from it, which dirties the page).
1066 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
1067=item aio_group $callback->(...) 1206=item aio_group $callback->(...)
1068 1207
1069This 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
1070container 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
1071many requests into a single, composite, request with a definite callback 1210many requests into a single, composite, request with a definite callback
… …
1294 1433
1295See C<poll_cb> for an example. 1434See C<poll_cb> for an example.
1296 1435
1297=item IO::AIO::poll_cb 1436=item IO::AIO::poll_cb
1298 1437
1299Process some outstanding events on the result pipe. You have to call this 1438Process 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 1439this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1440were 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 1441reason. Returns immediately when no events are outstanding. The amount of
1303C<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>.
1304 1444
1305If not all requests were processed for whatever reason, the filehandle 1445If 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 1446will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1447do anything special to have it called later.
1308 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
1309Example: Install an Event watcher that automatically calls 1456Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1457IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1458SYNOPSIS section, at the top of this document):
1312 1459
1313 Event->io (fd => IO::AIO::poll_fileno, 1460 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1461 poll => 'r', async => 1,
1315 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;
1316 1490
1317=item IO::AIO::max_poll_reqs $nreqs 1491=item IO::AIO::max_poll_reqs $nreqs
1318 1492
1319=item IO::AIO::max_poll_time $seconds 1493=item IO::AIO::max_poll_time $seconds
1320 1494
… …
1345 # use a low priority so other tasks have priority 1519 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1520 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1521 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1522 cb => &IO::AIO::poll_cb);
1349 1523
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 1524=back
1378 1525
1379=head3 CONTROLLING THE NUMBER OF THREADS 1526=head3 CONTROLLING THE NUMBER OF THREADS
1380 1527
1381=over 1528=over
… …
1414 1561
1415Under normal circumstances you don't need to call this function. 1562Under normal circumstances you don't need to call this function.
1416 1563
1417=item IO::AIO::max_idle $nthreads 1564=item IO::AIO::max_idle $nthreads
1418 1565
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1566Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1567(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1568timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1569C<$nthreads> other threads are also idle, it will free its resources and
1570exit.
1423 1571
1424This 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)
1425to allow for extremely high load situations, but want to free resources 1573to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1574under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1575
1428The default is probably ok in most situations, especially if thread 1576The default is probably ok in most situations, especially if thread
1429creation 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
1430want to use larger values. 1578want to use larger values.
1431 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
1432=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.
1433 1595
1434This 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
1435blocks, 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
1436use an C<aio_group> together with a feed callback. 1598use an C<aio_group> together with a feed callback.
1437 1599
1438Sets 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
1439do queue up more than this number of requests, the next call to the 1601a 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 1602
1443The default value is very large, so there is no practical limit on the 1603 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1604
1446You can still queue as many requests as you want. Therefore, 1605 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1606 aio_stat $path , ...;
1448as 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.
1449 1619
1450=back 1620=back
1451 1621
1452=head3 STATISTICAL INFORMATION 1622=head3 STATISTICAL INFORMATION
1453 1623
… …
1491 1661
1492Returns the number of bytes copied, or C<-1> on error. 1662Returns the number of bytes copied, or C<-1> on error.
1493 1663
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1664=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1665
1496Simply calls the C<posix_fadvise> function (see it's 1666Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1667manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1668avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1669C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1670C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1671
1502On systems that do not implement C<posix_fadvise>, this function returns 1672On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1673ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 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
1505=back 1761=back
1506 1762
1507=cut 1763=cut
1508 1764
1509min_parallel 8; 1765min_parallel 8;
1510 1766
1511END { flush } 1767END { flush }
1512 1768
15131; 17691;
1514 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
1515=head2 FORK BEHAVIOUR 1802=head2 FORK BEHAVIOUR
1516 1803
1517This 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.
1518 1810
1519Before the fork, IO::AIO enters a quiescent state where no requests 1811Some operating systems have extensions that allow safe use of fork, and
1520can 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
1521the fork the parent simply leaves the quiescent state and continues 1813the time of this writing (2011) only GNU/Linux supports these extensions
1522request/result processing, while the child frees the request/result queue 1814to POSIX.
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
1527In short: the parent will, after a short pause, continue as if fork had
1528not been called, while the child will act as if IO::AIO has not been used
1529yet.
1530 1815
1531=head2 MEMORY USAGE 1816=head2 MEMORY USAGE
1532 1817
1533Per-request usage: 1818Per-request usage:
1534 1819

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