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Revision 1.172 by root, Thu Jan 7 18:08:21 2010 UTC vs.
Revision 1.203 by root, Thu Jul 7 22:36:18 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_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_fsync $fh, $callback->($status)
243 aio_fdatasync $fh, $callback->($status)
244 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
245 aio_pathsync $path, $callback->($status)
246 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
247 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
248 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
249 aio_mlockall $flags, $callback->($status)
250 aio_group $callback->(...)
251 aio_nop $callback->()
252
253 $prev_pri = aioreq_pri [$pri]
254 aioreq_nice $pri_adjust
255
256 IO::AIO::poll_wait
257 IO::AIO::poll_cb
258 IO::AIO::poll
259 IO::AIO::flush
260 IO::AIO::max_poll_reqs $nreqs
261 IO::AIO::max_poll_time $seconds
262 IO::AIO::min_parallel $nthreads
263 IO::AIO::max_parallel $nthreads
264 IO::AIO::max_idle $nthreads
265 IO::AIO::idle_timeout $seconds
266 IO::AIO::max_outstanding $maxreqs
267 IO::AIO::nreqs
268 IO::AIO::nready
269 IO::AIO::npending
270
271 IO::AIO::sendfile $ofh, $ifh, $offset, $count
272 IO::AIO::fadvise $fh, $offset, $len, $advice
273 IO::AIO::madvise $scalar, $offset, $length, $advice
274 IO::AIO::mprotect $scalar, $offset, $length, $protect
275 IO::AIO::munlock $scalar, $offset = 0, $length = undef
276 IO::AIO::munlockall
223 277
224=head2 AIO REQUEST FUNCTIONS 278=head2 AIO REQUEST FUNCTIONS
225 279
226All the C<aio_*> calls are more or less thin wrappers around the syscall 280All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 281with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 361by the umask in effect then the request is being executed, so better never
308change the umask. 362change the umask.
309 363
310Example: 364Example:
311 365
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 366 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 367 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 368 print "open successful, fh is $_[0]\n";
315 ... 369 ...
316 } else { 370 } else {
317 die "open failed: $!\n"; 371 die "open failed: $!\n";
318 } 372 }
319 }; 373 };
320 374
375In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
376C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
377following POSIX and non-POSIX constants are available (missing ones on
378your system are, as usual, C<0>):
379
380C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
381C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
382C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
383
321 384
322=item aio_close $fh, $callback->($status) 385=item aio_close $fh, $callback->($status)
323 386
324Asynchronously close a file and call the callback with the result 387Asynchronously close a file and call the callback with the result
325code. 388code.
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375 438
376Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 439Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377reading at byte offset C<$in_offset>, and starts writing at the current 440reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 441file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 442than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 443other. The same C<$in_fh> works fine though, as this function does not
444move or use the file offset of C<$in_fh>.
381 445
446Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
447are written, and there is no way to find out how many more bytes have been
448read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
449number of bytes written to C<$out_fh>. Only if the result value equals
450C<$length> one can assume that C<$length> bytes have been read.
451
452Unlike with other C<aio_> functions, it makes a lot of sense to use
453C<aio_sendfile> on non-blocking sockets, as long as one end (typically
454the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
455the socket I/O will be non-blocking. Note, however, that you can run
456into a trap where C<aio_sendfile> reads some data with readahead, then
457fails to write all data, and when the socket is ready the next time, the
458data in the cache is already lost, forcing C<aio_sendfile> to again hit
459the disk. Explicit C<aio_read> + C<aio_write> let's you better control
460resource usage.
461
382This call tries to make use of a native C<sendfile> syscall to provide 462This call tries to make use of a native C<sendfile>-like syscall to
383zero-copy operation. For this to work, C<$out_fh> should refer to a 463provide zero-copy operation. For this to work, C<$out_fh> should refer to
384socket, and C<$in_fh> should refer to mmap'able file. 464a socket, and C<$in_fh> should refer to an mmap'able file.
385 465
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 466If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 467C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388it will be emulated, so you can call C<aio_sendfile> on any type of 468C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389filehandle regardless of the limitations of the operating system. 469type of filehandle regardless of the limitations of the operating system.
390 470
391Please note, however, that C<aio_sendfile> can read more bytes from 471As native sendfile syscalls (as practically any non-POSIX interface hacked
392C<$in_fh> than are written, and there is no way to find out how many 472together 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 473on many systems, this implementation tries to work around some known bugs
394provides the number of bytes written to C<$out_fh>. Only if the result 474in Linux and FreeBSD kernels (probably others, too), but that might fail,
395value equals C<$length> one can assume that C<$length> bytes have been 475so you really really should check the return value of C<aio_sendfile> -
396read. 476fewre bytes than expected might have been transferred.
397 477
398 478
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 479=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 480
401C<aio_readahead> populates the page cache with data from a file so that 481C<aio_readahead> populates the page cache with data from a file so that
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424 504
425Currently, the stats are always 64-bit-stats, i.e. instead of returning an 505Currently, 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 506error when stat'ing a large file, the results will be silently truncated
427unless perl itself is compiled with large file support. 507unless perl itself is compiled with large file support.
428 508
509To help interpret the mode and dev/rdev stat values, IO::AIO offers the
510following constants and functions (if not implemented, the constants will
511be C<0> and the functions will either C<croak> or fall back on traditional
512behaviour).
513
514C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
515C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
516C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
517
429Example: Print the length of F</etc/passwd>: 518Example: Print the length of F</etc/passwd>:
430 519
431 aio_stat "/etc/passwd", sub { 520 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 521 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 522 print "size is ", -s _, "\n";
434 }; 523 };
435 524
436 525
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 526=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 527
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 528Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 529whether a file handle or path was passed.
441 530
442On success, the callback is passed a hash reference with the following 531On success, the callback is passed a hash reference with the following
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534 623
535The only (POSIX-) portable way of calling this function is: 624The only (POSIX-) portable way of calling this function is:
536 625
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 626 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 627
628See C<aio_stat> for info about some potentially helpful extra constants
629and functions.
539 630
540=item aio_link $srcpath, $dstpath, $callback->($status) 631=item aio_link $srcpath, $dstpath, $callback->($status)
541 632
542Asynchronously create a new link to the existing object at C<$srcpath> at 633Asynchronously create a new link to the existing object at C<$srcpath> at
543the path C<$dstpath> and call the callback with the result code. 634the path C<$dstpath> and call the callback with the result code.
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554Asynchronously read the symlink specified by C<$path> and pass it to 645Asynchronously read the symlink specified by C<$path> and pass it to
555the callback. If an error occurs, nothing or undef gets passed to the 646the callback. If an error occurs, nothing or undef gets passed to the
556callback. 647callback.
557 648
558 649
650=item aio_realpath $path, $callback->($path)
651
652Asynchronously make the path absolute and resolve any symlinks in
653C<$path>. The resulting path only consists of directories (Same as
654L<Cwd::realpath>).
655
656This request can be used to get the absolute path of the current working
657directory by passing it a path of F<.> (a single dot).
658
659
559=item aio_rename $srcpath, $dstpath, $callback->($status) 660=item aio_rename $srcpath, $dstpath, $callback->($status)
560 661
561Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 662Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
562rename(2) and call the callback with the result code. 663rename(2) and call the callback with the result code.
563 664
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596 697
597=over 4 698=over 4
598 699
599=item IO::AIO::READDIR_DENTS 700=item IO::AIO::READDIR_DENTS
600 701
601When this flag is off, then the callback gets an arrayref with of names 702When this flag is off, then the callback gets an arrayref consisting of
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 703names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 704C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 705entry in more detail.
605 706
606C<$name> is the name of the entry. 707C<$name> is the name of the entry.
607 708
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620systems that do not deliver the inode information. 721systems that do not deliver the inode information.
621 722
622=item IO::AIO::READDIR_DIRS_FIRST 723=item IO::AIO::READDIR_DIRS_FIRST
623 724
624When this flag is set, then the names will be returned in an order where 725When this flag is set, then the names will be returned in an order where
625likely directories come first. This is useful when you need to quickly 726likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 727you need to quickly find directories, or you want to find all directories
627stat() each entry. 728while avoiding to stat() each entry.
628 729
629If the system returns type information in readdir, then this is used 730If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 731to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 732beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 733short names are tried first.
633 734
634=item IO::AIO::READDIR_STAT_ORDER 735=item IO::AIO::READDIR_STAT_ORDER
635 736
636When this flag is set, then the names will be returned in an order 737When this flag is set, then the names will be returned in an order
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781 if ($_[0] && $! == EXDEV) { 882 if ($_[0] && $! == EXDEV) {
782 aioreq_pri $pri; 883 aioreq_pri $pri;
783 add $grp aio_copy $src, $dst, sub { 884 add $grp aio_copy $src, $dst, sub {
784 $grp->result ($_[0]); 885 $grp->result ($_[0]);
785 886
786 if (!$_[0]) { 887 unless ($_[0]) {
787 aioreq_pri $pri; 888 aioreq_pri $pri;
788 add $grp aio_unlink $src; 889 add $grp aio_unlink $src;
789 } 890 }
790 }; 891 };
791 } else { 892 } else {
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1039} 1140}
1040 1141
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1142=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1143
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1144This 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 1145scalars (see the C<IO::AIO::mmap> function, although it also works on data
1146scalars 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 1147scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1148it).
1047 1149
1048It calls the C<msync> function of your OS, if available, with the memory 1150It 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 1151area 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> 1152later. 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 1153is 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 1164as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1165C<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 1166C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1167writing an octet from it, which dirties the page).
1066 1168
1169=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1170
1171This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1172scalars.
1173
1174It reads in all the pages of the underlying storage into memory (if any)
1175and locks them, so they are not getting swapped/paged out or removed.
1176
1177If C<$length> is undefined, then the scalar will be locked till the end.
1178
1179On systems that do not implement C<mlock>, this function returns C<-1>
1180and sets errno to C<ENOSYS>.
1181
1182Note that the corresponding C<munlock> is synchronous and is
1183documented under L<MISCELLANEOUS FUNCTIONS>.
1184
1185Example: open a file, mmap and mlock it - both will be undone when
1186C<$data> gets destroyed.
1187
1188 open my $fh, "<", $path or die "$path: $!";
1189 my $data;
1190 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1191 aio_mlock $data; # mlock in background
1192
1193=item aio_mlockall $flags, $callback->($status)
1194
1195Calls the C<mlockall> function with the given C<$flags> (a combination of
1196C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1197
1198On systems that do not implement C<mlockall>, this function returns C<-1>
1199and sets errno to C<ENOSYS>.
1200
1201Note that the corresponding C<munlockall> is synchronous and is
1202documented under L<MISCELLANEOUS FUNCTIONS>.
1203
1204Example: asynchronously lock all current and future pages into memory.
1205
1206 aio_mlockall IO::AIO::MCL_FUTURE;
1207
1067=item aio_group $callback->(...) 1208=item aio_group $callback->(...)
1068 1209
1069This is a very special aio request: Instead of doing something, it is a 1210This 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 1211container for other aio requests, which is useful if you want to bundle
1071many requests into a single, composite, request with a definite callback 1212many requests into a single, composite, request with a definite callback
… …
1294 1435
1295See C<poll_cb> for an example. 1436See C<poll_cb> for an example.
1296 1437
1297=item IO::AIO::poll_cb 1438=item IO::AIO::poll_cb
1298 1439
1299Process some outstanding events on the result pipe. You have to call this 1440Process 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 1441this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1442were 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 1443reason. Returns immediately when no events are outstanding. The amount of
1303C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1444events processed depends on the settings of C<IO::AIO::max_poll_req> and
1445C<IO::AIO::max_poll_time>.
1304 1446
1305If not all requests were processed for whatever reason, the filehandle 1447If 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 1448will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1449do anything special to have it called later.
1308 1450
1451Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1452ready, it can be beneficial to call this function from loops which submit
1453a lot of requests, to make sure the results get processed when they become
1454available and not just when the loop is finished and the event loop takes
1455over again. This function returns very fast when there are no outstanding
1456requests.
1457
1309Example: Install an Event watcher that automatically calls 1458Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1459IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1460SYNOPSIS section, at the top of this document):
1312 1461
1313 Event->io (fd => IO::AIO::poll_fileno, 1462 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1463 poll => 'r', async => 1,
1315 cb => \&IO::AIO::poll_cb); 1464 cb => \&IO::AIO::poll_cb);
1465
1466=item IO::AIO::poll_wait
1467
1468If there are any outstanding requests and none of them in the result
1469phase, wait till the result filehandle becomes ready for reading (simply
1470does a C<select> on the filehandle. This is useful if you want to
1471synchronously wait for some requests to finish).
1472
1473See C<nreqs> for an example.
1474
1475=item IO::AIO::poll
1476
1477Waits until some requests have been handled.
1478
1479Returns the number of requests processed, but is otherwise strictly
1480equivalent to:
1481
1482 IO::AIO::poll_wait, IO::AIO::poll_cb
1483
1484=item IO::AIO::flush
1485
1486Wait till all outstanding AIO requests have been handled.
1487
1488Strictly equivalent to:
1489
1490 IO::AIO::poll_wait, IO::AIO::poll_cb
1491 while IO::AIO::nreqs;
1316 1492
1317=item IO::AIO::max_poll_reqs $nreqs 1493=item IO::AIO::max_poll_reqs $nreqs
1318 1494
1319=item IO::AIO::max_poll_time $seconds 1495=item IO::AIO::max_poll_time $seconds
1320 1496
… …
1345 # use a low priority so other tasks have priority 1521 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1522 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1523 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1524 cb => &IO::AIO::poll_cb);
1349 1525
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 1526=back
1378 1527
1379=head3 CONTROLLING THE NUMBER OF THREADS 1528=head3 CONTROLLING THE NUMBER OF THREADS
1380 1529
1381=over 1530=over
… …
1414 1563
1415Under normal circumstances you don't need to call this function. 1564Under normal circumstances you don't need to call this function.
1416 1565
1417=item IO::AIO::max_idle $nthreads 1566=item IO::AIO::max_idle $nthreads
1418 1567
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1568Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1569(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1570timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1571C<$nthreads> other threads are also idle, it will free its resources and
1572exit.
1423 1573
1424This is useful when you allow a large number of threads (e.g. 100 or 1000) 1574This 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 1575to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1576under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1577
1428The default is probably ok in most situations, especially if thread 1578The default is probably ok in most situations, especially if thread
1429creation is fast. If thread creation is very slow on your system you might 1579creation is fast. If thread creation is very slow on your system you might
1430want to use larger values. 1580want to use larger values.
1431 1581
1582=item IO::AIO::idle_timeout $seconds
1583
1584Sets the minimum idle timeout (default 10) after which worker threads are
1585allowed to exit. SEe C<IO::AIO::max_idle>.
1586
1432=item IO::AIO::max_outstanding $maxreqs 1587=item IO::AIO::max_outstanding $maxreqs
1588
1589Sets the maximum number of outstanding requests to C<$nreqs>. If
1590you do queue up more than this number of requests, the next call to
1591C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1592C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1593longer exceeded.
1594
1595In other words, this setting does not enforce a queue limit, but can be
1596used to make poll functions block if the limit is exceeded.
1433 1597
1434This is a very bad function to use in interactive programs because it 1598This 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 1599blocks, and a bad way to reduce concurrency because it is inexact: Better
1436use an C<aio_group> together with a feed callback. 1600use an C<aio_group> together with a feed callback.
1437 1601
1438Sets the maximum number of outstanding requests to C<$nreqs>. If you 1602It'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 1603a 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 1604
1443The default value is very large, so there is no practical limit on the 1605 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1606
1446You can still queue as many requests as you want. Therefore, 1607 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1608 aio_stat $path , ...;
1448as a stop gap to shield against fatal memory overflow (with large values). 1609 IO::AIO::poll_cb;
1610 }
1611
1612 IO::AIO::flush;
1613
1614The call to C<poll_cb> inside the loop will normally return instantly, but
1615as soon as more thna C<32> reqeusts are in-flight, it will block until
1616some requests have been handled. This keeps the loop from pushing a large
1617number of C<aio_stat> requests onto the queue.
1618
1619The default value for C<max_outstanding> is very large, so there is no
1620practical limit on the number of outstanding requests.
1449 1621
1450=back 1622=back
1451 1623
1452=head3 STATISTICAL INFORMATION 1624=head3 STATISTICAL INFORMATION
1453 1625
… …
1491 1663
1492Returns the number of bytes copied, or C<-1> on error. 1664Returns the number of bytes copied, or C<-1> on error.
1493 1665
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1666=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1667
1496Simply calls the C<posix_fadvise> function (see it's 1668Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1669manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1670avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1671C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1672C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1673
1502On systems that do not implement C<posix_fadvise>, this function returns 1674On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1675ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 1676
1677=item IO::AIO::madvise $scalar, $offset, $len, $advice
1678
1679Simply calls the C<posix_madvise> function (see its
1680manpage for details). The following advice constants are
1681avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1682C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1683
1684On systems that do not implement C<posix_madvise>, this function returns
1685ENOSYS, otherwise the return value of C<posix_madvise>.
1686
1687=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1688
1689Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1690$scalar (see its manpage for details). The following protect
1691constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1692C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1693
1694On systems that do not implement C<mprotect>, this function returns
1695ENOSYS, otherwise the return value of C<mprotect>.
1696
1697=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1698
1699Memory-maps a file (or anonymous memory range) and attaches it to the
1700given C<$scalar>, which will act like a string scalar.
1701
1702The only operations allowed on the scalar are C<substr>/C<vec> that don't
1703change the string length, and most read-only operations such as copying it
1704or searching it with regexes and so on.
1705
1706Anything else is unsafe and will, at best, result in memory leaks.
1707
1708The memory map associated with the C<$scalar> is automatically removed
1709when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1710C<IO::AIO::munmap> functions are called.
1711
1712This calls the C<mmap>(2) function internally. See your system's manual
1713page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1714
1715The C<$length> must be larger than zero and smaller than the actual
1716filesize.
1717
1718C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1719C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1720
1721C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1722C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1723not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1724(which is set to C<MAP_ANON> if your system only provides this
1725constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1726C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1727C<IO::AIO::MAP_NONBLOCK>
1728
1729If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1730
1731C<$offset> is the offset from the start of the file - it generally must be
1732a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1733
1734Example:
1735
1736 use Digest::MD5;
1737 use IO::AIO;
1738
1739 open my $fh, "<verybigfile"
1740 or die "$!";
1741
1742 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1743 or die "verybigfile: $!";
1744
1745 my $fast_md5 = md5 $data;
1746
1747=item IO::AIO::munmap $scalar
1748
1749Removes a previous mmap and undefines the C<$scalar>.
1750
1751=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1752
1753Calls the C<munlock> function, undoing the effects of a previous
1754C<aio_mlock> call (see its description for details).
1755
1756=item IO::AIO::munlockall
1757
1758Calls the C<munlockall> function.
1759
1760On systems that do not implement C<munlockall>, this function returns
1761ENOSYS, otherwise the return value of C<munlockall>.
1762
1505=back 1763=back
1506 1764
1507=cut 1765=cut
1508 1766
1509min_parallel 8; 1767min_parallel 8;
1510 1768
1511END { flush } 1769END { flush }
1512 1770
15131; 17711;
1514 1772
1773=head1 EVENT LOOP INTEGRATION
1774
1775It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1776automatically into many event loops:
1777
1778 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1779 use AnyEvent::AIO;
1780
1781You can also integrate IO::AIO manually into many event loops, here are
1782some examples of how to do this:
1783
1784 # EV integration
1785 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1786
1787 # Event integration
1788 Event->io (fd => IO::AIO::poll_fileno,
1789 poll => 'r',
1790 cb => \&IO::AIO::poll_cb);
1791
1792 # Glib/Gtk2 integration
1793 add_watch Glib::IO IO::AIO::poll_fileno,
1794 in => sub { IO::AIO::poll_cb; 1 };
1795
1796 # Tk integration
1797 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1798 readable => \&IO::AIO::poll_cb);
1799
1800 # Danga::Socket integration
1801 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1802 \&IO::AIO::poll_cb);
1803
1515=head2 FORK BEHAVIOUR 1804=head2 FORK BEHAVIOUR
1516 1805
1517This module should do "the right thing" when the process using it forks: 1806Usage of pthreads in a program changes the semantics of fork
1807considerably. Specifically, only async-safe functions can be called after
1808fork. Perl doesn't know about this, so in general, you cannot call fork
1809with defined behaviour in perl. IO::AIO uses pthreads, so this applies,
1810but many other extensions and (for inexplicable reasons) perl itself often
1811is linked against pthreads, so this limitation applies.
1518 1812
1519Before the fork, IO::AIO enters a quiescent state where no requests 1813Some operating systems have extensions that allow safe use of fork, and
1520can be added in other threads and no results will be processed. After 1814this module should do "the right thing" on those, and tries on others. At
1521the fork the parent simply leaves the quiescent state and continues 1815the time of this writing (2011) only GNU/Linux supports these extensions
1522request/result processing, while the child frees the request/result queue 1816to 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 1817
1531=head2 MEMORY USAGE 1818=head2 MEMORY USAGE
1532 1819
1533Per-request usage: 1820Per-request usage:
1534 1821

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