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Revision 1.174 by root, Sun Jan 10 20:28:43 2010 UTC vs.
Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC

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4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10 my $fh = shift 10 my $fh = shift
11 or die "/etc/passwd: $!"; 11 or die "/etc/passwd: $!";
12 ... 12 ...
13 }; 13 };
14 14
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25 my $req = aio_unlink "/tmp/file", sub { }; 25 my $req = aio_unlink "/tmp/file", sub { };
26 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
27 27
28 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
29 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r',
40 cb => \&IO::AIO::poll_cb);
41
42 # Glib/Gtk2 integration
43 add_watch Glib::IO IO::AIO::poll_fileno,
44 in => sub { IO::AIO::poll_cb; 1 };
45
46 # Tk integration
47 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48 readable => \&IO::AIO::poll_cb);
49
50 # Danga::Socket integration
51 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52 \&IO::AIO::poll_cb);
53 30
54=head1 DESCRIPTION 31=head1 DESCRIPTION
55 32
56This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
57operating system supports. It is implemented as an interface to C<libeio> 34operating system supports. It is implemented as an interface to C<libeio>
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99 76
100 # register the IO::AIO callback with EV 77 # register the IO::AIO callback with EV
101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 79
103 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105 my $fh = shift 82 my $fh = shift
106 or die "error while opening: $!"; 83 or die "error while opening: $!";
107 84
108 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh; 86 my $size = -s $fh;
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191use common::sense; 168use common::sense;
192 169
193use base 'Exporter'; 170use base 'Exporter';
194 171
195BEGIN { 172BEGIN {
196 our $VERSION = '3.5'; 173 our $VERSION = '3.9';
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_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_rename $srcpath, $dstpath, $callback->($status)
228 aio_mkdir $pathname, $mode, $callback->($status)
229 aio_rmdir $pathname, $callback->($status)
230 aio_readdir $pathname, $callback->($entries)
231 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
234 aio_load $path, $data, $callback->($status)
235 aio_copy $srcpath, $dstpath, $callback->($status)
236 aio_move $srcpath, $dstpath, $callback->($status)
237 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238 aio_rmtree $path, $callback->($status)
239 aio_sync $callback->($status)
240 aio_fsync $fh, $callback->($status)
241 aio_fdatasync $fh, $callback->($status)
242 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243 aio_pathsync $path, $callback->($status)
244 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247 aio_mlockall $flags, $callback->($status)
248 aio_group $callback->(...)
249 aio_nop $callback->()
250
251 $prev_pri = aioreq_pri [$pri]
252 aioreq_nice $pri_adjust
253
254 IO::AIO::poll_wait
255 IO::AIO::poll_cb
256 IO::AIO::poll
257 IO::AIO::flush
258 IO::AIO::max_poll_reqs $nreqs
259 IO::AIO::max_poll_time $seconds
260 IO::AIO::min_parallel $nthreads
261 IO::AIO::max_parallel $nthreads
262 IO::AIO::max_idle $nthreads
263 IO::AIO::idle_timeout $seconds
264 IO::AIO::max_outstanding $maxreqs
265 IO::AIO::nreqs
266 IO::AIO::nready
267 IO::AIO::npending
268
269 IO::AIO::sendfile $ofh, $ifh, $offset, $count
270 IO::AIO::fadvise $fh, $offset, $len, $advice
271 IO::AIO::madvise $scalar, $offset, $length, $advice
272 IO::AIO::mprotect $scalar, $offset, $length, $protect
273 IO::AIO::munlock $scalar, $offset = 0, $length = undef
274 IO::AIO::munlockall
223 275
224=head2 AIO REQUEST FUNCTIONS 276=head2 AIO REQUEST FUNCTIONS
225 277
226All the C<aio_*> calls are more or less thin wrappers around the syscall 278All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 279with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 359by the umask in effect then the request is being executed, so better never
308change the umask. 360change the umask.
309 361
310Example: 362Example:
311 363
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 364 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 365 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 366 print "open successful, fh is $_[0]\n";
315 ... 367 ...
316 } else { 368 } else {
317 die "open failed: $!\n"; 369 die "open failed: $!\n";
318 } 370 }
319 }; 371 };
320 372
373In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
374C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
375following POSIX and non-POSIX constants are available (missing ones on
376your system are, as usual, C<0>):
377
378C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
379C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
380C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
381
321 382
322=item aio_close $fh, $callback->($status) 383=item aio_close $fh, $callback->($status)
323 384
324Asynchronously close a file and call the callback with the result 385Asynchronously close a file and call the callback with the result
325code. 386code.
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377reading at byte offset C<$in_offset>, and starts writing at the current 438reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 439file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 440than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 441other.
381 442
443Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
444are written, and there is no way to find out how many bytes have been read
445from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
446bytes written to C<$out_fh>. Only if the result value equals C<$length>
447one can assume that C<$length> bytes have been read.
448
449Unlike with other C<aio_> functions, it makes a lot of sense to use
450C<aio_sendfile> on non-blocking sockets, as long as one end (typically
451the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
452the socket I/O will be non-blocking. Note, however, that you can run into
453a trap where C<aio_sendfile> reads some data with readahead, then fails
454to write all data, and when the socket is ready the next time, the data
455in the cache is already lost, forcing C<aio_sendfile> to again hit the
456disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
457much better.
458
382This call tries to make use of a native C<sendfile> syscall to provide 459This call tries to make use of a native C<sendfile> syscall to provide
383zero-copy operation. For this to work, C<$out_fh> should refer to a 460zero-copy operation. For this to work, C<$out_fh> should refer to a
384socket, and C<$in_fh> should refer to mmap'able file. 461socket, and C<$in_fh> should refer to an mmap'able file.
385 462
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 463If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 464C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
388it will be emulated, so you can call C<aio_sendfile> on any type of 465it will be emulated, so you can call C<aio_sendfile> on any type of
389filehandle regardless of the limitations of the operating system. 466filehandle regardless of the limitations of the operating system.
390
391Please note, however, that C<aio_sendfile> can read more bytes from
392C<$in_fh> than are written, and there is no way to find out how many
393bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
394provides the number of bytes written to C<$out_fh>. Only if the result
395value equals C<$length> one can assume that C<$length> bytes have been
396read.
397 467
398 468
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 469=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 470
401C<aio_readahead> populates the page cache with data from a file so that 471C<aio_readahead> populates the page cache with data from a file so that
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424 494
425Currently, the stats are always 64-bit-stats, i.e. instead of returning an 495Currently, 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 496error when stat'ing a large file, the results will be silently truncated
427unless perl itself is compiled with large file support. 497unless perl itself is compiled with large file support.
428 498
499To help interpret the mode and dev/rdev stat values, IO::AIO offers the
500following constants and functions (if not implemented, the constants will
501be C<0> and the functions will either C<croak> or fall back on traditional
502behaviour).
503
504C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
505C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
506C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
507
429Example: Print the length of F</etc/passwd>: 508Example: Print the length of F</etc/passwd>:
430 509
431 aio_stat "/etc/passwd", sub { 510 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 511 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 512 print "size is ", -s _, "\n";
434 }; 513 };
435 514
436 515
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 516=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 517
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 518Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 519whether a file handle or path was passed.
441 520
442On success, the callback is passed a hash reference with the following 521On success, the callback is passed a hash reference with the following
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534 613
535The only (POSIX-) portable way of calling this function is: 614The only (POSIX-) portable way of calling this function is:
536 615
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 616 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 617
618See C<aio_stat> for info about some potentially helpful extra constants
619and functions.
539 620
540=item aio_link $srcpath, $dstpath, $callback->($status) 621=item aio_link $srcpath, $dstpath, $callback->($status)
541 622
542Asynchronously create a new link to the existing object at C<$srcpath> at 623Asynchronously create a new link to the existing object at C<$srcpath> at
543the path C<$dstpath> and call the callback with the result code. 624the path C<$dstpath> and call the callback with the result code.
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596 677
597=over 4 678=over 4
598 679
599=item IO::AIO::READDIR_DENTS 680=item IO::AIO::READDIR_DENTS
600 681
601When this flag is off, then the callback gets an arrayref with of names 682When this flag is off, then the callback gets an arrayref consisting of
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 683names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 684C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 685entry in more detail.
605 686
606C<$name> is the name of the entry. 687C<$name> is the name of the entry.
607 688
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620systems that do not deliver the inode information. 701systems that do not deliver the inode information.
621 702
622=item IO::AIO::READDIR_DIRS_FIRST 703=item IO::AIO::READDIR_DIRS_FIRST
623 704
624When this flag is set, then the names will be returned in an order where 705When 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 706likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 707you need to quickly find directories, or you want to find all directories
627stat() each entry. 708while avoiding to stat() each entry.
628 709
629If the system returns type information in readdir, then this is used 710If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 711to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 712beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 713short names are tried first.
633 714
634=item IO::AIO::READDIR_STAT_ORDER 715=item IO::AIO::READDIR_STAT_ORDER
635 716
636When this flag is set, then the names will be returned in an order 717When this flag is set, then the names will be returned in an order
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1039} 1120}
1040 1121
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1122=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1123
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1124This 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 1125scalars (see the C<IO::AIO::mmap> function, although it also works on data
1126scalars 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 1127scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1128it).
1047 1129
1048It calls the C<msync> function of your OS, if available, with the memory 1130It 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 1131area 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> 1132later. 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 1133is 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 1144as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1145C<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 1146C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1147writing an octet from it, which dirties the page).
1066 1148
1149=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1150
1151This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1152scalars.
1153
1154It reads in all the pages of the underlying storage into memory (if any)
1155and locks them, so they are not getting swapped/paged out or removed.
1156
1157If C<$length> is undefined, then the scalar will be locked till the end.
1158
1159On systems that do not implement C<mlock>, this function returns C<-1>
1160and sets errno to C<ENOSYS>.
1161
1162Note that the corresponding C<munlock> is synchronous and is
1163documented under L<MISCELLANEOUS FUNCTIONS>.
1164
1165Example: open a file, mmap and mlock it - both will be undone when
1166C<$data> gets destroyed.
1167
1168 open my $fh, "<", $path or die "$path: $!";
1169 my $data;
1170 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1171 aio_mlock $data; # mlock in background
1172
1173=item aio_mlockall $flags, $callback->($status)
1174
1175Calls the C<mlockall> function with the given C<$flags> (a combination of
1176C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1177
1178On systems that do not implement C<mlockall>, this function returns C<-1>
1179and sets errno to C<ENOSYS>.
1180
1181Note that the corresponding C<munlockall> is synchronous and is
1182documented under L<MISCELLANEOUS FUNCTIONS>.
1183
1184Example: asynchronously lock all current and future pages into memory.
1185
1186 aio_mlockall IO::AIO::MCL_FUTURE;
1187
1067=item aio_group $callback->(...) 1188=item aio_group $callback->(...)
1068 1189
1069This is a very special aio request: Instead of doing something, it is a 1190This 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 1191container for other aio requests, which is useful if you want to bundle
1071many requests into a single, composite, request with a definite callback 1192many requests into a single, composite, request with a definite callback
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1294 1415
1295See C<poll_cb> for an example. 1416See C<poll_cb> for an example.
1296 1417
1297=item IO::AIO::poll_cb 1418=item IO::AIO::poll_cb
1298 1419
1299Process some outstanding events on the result pipe. You have to call this 1420Process 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 1421this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1422were 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 1423reason. Returns immediately when no events are outstanding. The amount of
1303C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1424events processed depends on the settings of C<IO::AIO::max_poll_req> and
1425C<IO::AIO::max_poll_time>.
1304 1426
1305If not all requests were processed for whatever reason, the filehandle 1427If 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 1428will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1429do anything special to have it called later.
1308 1430
1431Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1432ready, it can be beneficial to call this function from loops which submit
1433a lot of requests, to make sure the results get processed when they become
1434available and not just when the loop is finished and the event loop takes
1435over again. This function returns very fast when there are no outstanding
1436requests.
1437
1309Example: Install an Event watcher that automatically calls 1438Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1439IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1440SYNOPSIS section, at the top of this document):
1312 1441
1313 Event->io (fd => IO::AIO::poll_fileno, 1442 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1443 poll => 'r', async => 1,
1315 cb => \&IO::AIO::poll_cb); 1444 cb => \&IO::AIO::poll_cb);
1445
1446=item IO::AIO::poll_wait
1447
1448If there are any outstanding requests and none of them in the result
1449phase, wait till the result filehandle becomes ready for reading (simply
1450does a C<select> on the filehandle. This is useful if you want to
1451synchronously wait for some requests to finish).
1452
1453See C<nreqs> for an example.
1454
1455=item IO::AIO::poll
1456
1457Waits until some requests have been handled.
1458
1459Returns the number of requests processed, but is otherwise strictly
1460equivalent to:
1461
1462 IO::AIO::poll_wait, IO::AIO::poll_cb
1463
1464=item IO::AIO::flush
1465
1466Wait till all outstanding AIO requests have been handled.
1467
1468Strictly equivalent to:
1469
1470 IO::AIO::poll_wait, IO::AIO::poll_cb
1471 while IO::AIO::nreqs;
1316 1472
1317=item IO::AIO::max_poll_reqs $nreqs 1473=item IO::AIO::max_poll_reqs $nreqs
1318 1474
1319=item IO::AIO::max_poll_time $seconds 1475=item IO::AIO::max_poll_time $seconds
1320 1476
… …
1345 # use a low priority so other tasks have priority 1501 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1502 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1503 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1504 cb => &IO::AIO::poll_cb);
1349 1505
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 1506=back
1378 1507
1379=head3 CONTROLLING THE NUMBER OF THREADS 1508=head3 CONTROLLING THE NUMBER OF THREADS
1380 1509
1381=over 1510=over
… …
1414 1543
1415Under normal circumstances you don't need to call this function. 1544Under normal circumstances you don't need to call this function.
1416 1545
1417=item IO::AIO::max_idle $nthreads 1546=item IO::AIO::max_idle $nthreads
1418 1547
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1548Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1549(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1550timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1551C<$nthreads> other threads are also idle, it will free its resources and
1552exit.
1423 1553
1424This is useful when you allow a large number of threads (e.g. 100 or 1000) 1554This 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 1555to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1556under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1557
1428The default is probably ok in most situations, especially if thread 1558The default is probably ok in most situations, especially if thread
1429creation is fast. If thread creation is very slow on your system you might 1559creation is fast. If thread creation is very slow on your system you might
1430want to use larger values. 1560want to use larger values.
1431 1561
1562=item IO::AIO::idle_timeout $seconds
1563
1564Sets the minimum idle timeout (default 10) after which worker threads are
1565allowed to exit. SEe C<IO::AIO::max_idle>.
1566
1432=item IO::AIO::max_outstanding $maxreqs 1567=item IO::AIO::max_outstanding $maxreqs
1568
1569Sets the maximum number of outstanding requests to C<$nreqs>. If
1570you do queue up more than this number of requests, the next call to
1571C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1572C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1573longer exceeded.
1574
1575In other words, this setting does not enforce a queue limit, but can be
1576used to make poll functions block if the limit is exceeded.
1433 1577
1434This is a very bad function to use in interactive programs because it 1578This 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 1579blocks, and a bad way to reduce concurrency because it is inexact: Better
1436use an C<aio_group> together with a feed callback. 1580use an C<aio_group> together with a feed callback.
1437 1581
1438Sets the maximum number of outstanding requests to C<$nreqs>. If you 1582It'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 1583a 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 1584
1443The default value is very large, so there is no practical limit on the 1585 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1586
1446You can still queue as many requests as you want. Therefore, 1587 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1588 aio_stat $path , ...;
1448as a stop gap to shield against fatal memory overflow (with large values). 1589 IO::AIO::poll_cb;
1590 }
1591
1592 IO::AIO::flush;
1593
1594The call to C<poll_cb> inside the loop will normally return instantly, but
1595as soon as more thna C<32> reqeusts are in-flight, it will block until
1596some requests have been handled. This keeps the loop from pushing a large
1597number of C<aio_stat> requests onto the queue.
1598
1599The default value for C<max_outstanding> is very large, so there is no
1600practical limit on the number of outstanding requests.
1449 1601
1450=back 1602=back
1451 1603
1452=head3 STATISTICAL INFORMATION 1604=head3 STATISTICAL INFORMATION
1453 1605
… …
1491 1643
1492Returns the number of bytes copied, or C<-1> on error. 1644Returns the number of bytes copied, or C<-1> on error.
1493 1645
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1646=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1647
1496Simply calls the C<posix_fadvise> function (see it's 1648Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1649manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1650avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1651C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1652C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1653
1502On systems that do not implement C<posix_fadvise>, this function returns 1654On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1655ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 1656
1505=item IO::AIO::mlockall $flags 1657=item IO::AIO::madvise $scalar, $offset, $len, $advice
1506 1658
1507Calls the C<mlockall> function with the given C<$flags> (a combination of 1659Simply calls the C<posix_madvise> function (see its
1508C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>). 1660manpage for details). The following advice constants are
1661avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1662C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1509 1663
1664On systems that do not implement C<posix_madvise>, this function returns
1665ENOSYS, otherwise the return value of C<posix_madvise>.
1666
1667=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1668
1669Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1670$scalar (see its manpage for details). The following protect
1671constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1672C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1673
1510On systems that do not implement C<mlockall>, this function returns 1674On systems that do not implement C<mprotect>, this function returns
1511ENOSYS, otherwise the return value of C<mlockall>. 1675ENOSYS, otherwise the return value of C<mprotect>.
1676
1677=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1678
1679Memory-maps a file (or anonymous memory range) and attaches it to the
1680given C<$scalar>, which will act like a string scalar.
1681
1682The only operations allowed on the scalar are C<substr>/C<vec> that don't
1683change the string length, and most read-only operations such as copying it
1684or searching it with regexes and so on.
1685
1686Anything else is unsafe and will, at best, result in memory leaks.
1687
1688The memory map associated with the C<$scalar> is automatically removed
1689when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1690C<IO::AIO::munmap> functions are called.
1691
1692This calls the C<mmap>(2) function internally. See your system's manual
1693page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1694
1695The C<$length> must be larger than zero and smaller than the actual
1696filesize.
1697
1698C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1699C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1700
1701C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1702C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1703not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1704(which is set to C<MAP_ANON> if your system only provides this
1705constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1706C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1707C<IO::AIO::MAP_NONBLOCK>
1708
1709If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1710
1711C<$offset> is the offset from the start of the file - it generally must be
1712a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1713
1714Example:
1715
1716 use Digest::MD5;
1717 use IO::AIO;
1718
1719 open my $fh, "<verybigfile"
1720 or die "$!";
1721
1722 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1723 or die "verybigfile: $!";
1724
1725 my $fast_md5 = md5 $data;
1726
1727=item IO::AIO::munmap $scalar
1728
1729Removes a previous mmap and undefines the C<$scalar>.
1730
1731=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1732
1733Calls the C<munlock> function, undoing the effects of a previous
1734C<aio_mlock> call (see its description for details).
1512 1735
1513=item IO::AIO::munlockall 1736=item IO::AIO::munlockall
1514 1737
1515Calls the C<munlockall> function. 1738Calls the C<munlockall> function.
1516 1739
… …
1524min_parallel 8; 1747min_parallel 8;
1525 1748
1526END { flush } 1749END { flush }
1527 1750
15281; 17511;
1752
1753=head1 EVENT LOOP INTEGRATION
1754
1755It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1756automatically into many event loops:
1757
1758 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1759 use AnyEvent::AIO;
1760
1761You can also integrate IO::AIO manually into many event loops, here are
1762some examples of how to do this:
1763
1764 # EV integration
1765 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1766
1767 # Event integration
1768 Event->io (fd => IO::AIO::poll_fileno,
1769 poll => 'r',
1770 cb => \&IO::AIO::poll_cb);
1771
1772 # Glib/Gtk2 integration
1773 add_watch Glib::IO IO::AIO::poll_fileno,
1774 in => sub { IO::AIO::poll_cb; 1 };
1775
1776 # Tk integration
1777 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1778 readable => \&IO::AIO::poll_cb);
1779
1780 # Danga::Socket integration
1781 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1782 \&IO::AIO::poll_cb);
1529 1783
1530=head2 FORK BEHAVIOUR 1784=head2 FORK BEHAVIOUR
1531 1785
1532This module should do "the right thing" when the process using it forks: 1786This module should do "the right thing" when the process using it forks:
1533 1787

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