ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/IO-AIO/README
(Generate patch)

Comparing IO-AIO/README (file contents):
Revision 1.39 by root, Wed Aug 5 11:53:16 2009 UTC vs.
Revision 1.47 by root, Fri May 27 00:44:49 2011 UTC

… …
2 IO::AIO - Asynchronous Input/Output 2 IO::AIO - Asynchronous Input/Output
3 3
4SYNOPSIS 4SYNOPSIS
5 use IO::AIO; 5 use IO::AIO;
6 6
7 aio_open "/etc/passwd", O_RDONLY, 0, sub { 7 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
8 my $fh = shift 8 my $fh = shift
9 or die "/etc/passwd: $!"; 9 or die "/etc/passwd: $!";
10 ... 10 ...
11 }; 11 };
12 12
… …
23 my $req = aio_unlink "/tmp/file", sub { }; 23 my $req = aio_unlink "/tmp/file", sub { };
24 $req->cancel; # cancel request if still in queue 24 $req->cancel; # cancel request if still in queue
25 25
26 my $grp = aio_group sub { print "all stats done\n" }; 26 my $grp = aio_group sub { print "all stats done\n" };
27 add $grp aio_stat "..." for ...; 27 add $grp aio_stat "..." for ...;
28
29 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
30 use AnyEvent::AIO;
31
32 # EV integration
33 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
34
35 # Event integration
36 Event->io (fd => IO::AIO::poll_fileno,
37 poll => 'r',
38 cb => \&IO::AIO::poll_cb);
39
40 # Glib/Gtk2 integration
41 add_watch Glib::IO IO::AIO::poll_fileno,
42 in => sub { IO::AIO::poll_cb; 1 };
43
44 # Tk integration
45 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46 readable => \&IO::AIO::poll_cb);
47
48 # Danga::Socket integration
49 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50 \&IO::AIO::poll_cb);
51 28
52DESCRIPTION 29DESCRIPTION
53 This module implements asynchronous I/O using whatever means your 30 This module implements asynchronous I/O using whatever means your
54 operating system supports. It is implemented as an interface to "libeio" 31 operating system supports. It is implemented as an interface to "libeio"
55 (<http://software.schmorp.de/pkg/libeio.html>). 32 (<http://software.schmorp.de/pkg/libeio.html>).
… …
95 72
96 # register the IO::AIO callback with EV 73 # register the IO::AIO callback with EV
97 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 74 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98 75
99 # queue the request to open /etc/passwd 76 # queue the request to open /etc/passwd
100 aio_open "/etc/passwd", O_RDONLY, 0, sub { 77 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
101 my $fh = shift 78 my $fh = shift
102 or die "error while opening: $!"; 79 or die "error while opening: $!";
103 80
104 # stat'ing filehandles is generally non-blocking 81 # stat'ing filehandles is generally non-blocking
105 my $size = -s $fh; 82 my $size = -s $fh;
… …
168 anymore (except possibly for the Perl object, but its connection to 145 anymore (except possibly for the Perl object, but its connection to
169 the actual aio request is severed and calling its methods will 146 the actual aio request is severed and calling its methods will
170 either do nothing or result in a runtime error). 147 either do nothing or result in a runtime error).
171 148
172FUNCTIONS 149FUNCTIONS
150 QUICK OVERVIEW
151 This section simply lists the prototypes of the most important functions
152 for quick reference. See the following sections for function-by-function
153 documentation.
154
155 aio_open $pathname, $flags, $mode, $callback->($fh)
156 aio_close $fh, $callback->($status)
157 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
158 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
159 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
160 aio_readahead $fh,$offset,$length, $callback->($retval)
161 aio_stat $fh_or_path, $callback->($status)
162 aio_lstat $fh, $callback->($status)
163 aio_statvfs $fh_or_path, $callback->($statvfs)
164 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
165 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
166 aio_truncate $fh_or_path, $offset, $callback->($status)
167 aio_chmod $fh_or_path, $mode, $callback->($status)
168 aio_unlink $pathname, $callback->($status)
169 aio_mknod $path, $mode, $dev, $callback->($status)
170 aio_link $srcpath, $dstpath, $callback->($status)
171 aio_symlink $srcpath, $dstpath, $callback->($status)
172 aio_readlink $path, $callback->($link)
173 aio_rename $srcpath, $dstpath, $callback->($status)
174 aio_mkdir $pathname, $mode, $callback->($status)
175 aio_rmdir $pathname, $callback->($status)
176 aio_readdir $pathname, $callback->($entries)
177 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
178 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
179 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
180 aio_load $path, $data, $callback->($status)
181 aio_copy $srcpath, $dstpath, $callback->($status)
182 aio_move $srcpath, $dstpath, $callback->($status)
183 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
184 aio_rmtree $path, $callback->($status)
185 aio_sync $callback->($status)
186 aio_fsync $fh, $callback->($status)
187 aio_fdatasync $fh, $callback->($status)
188 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
189 aio_pathsync $path, $callback->($status)
190 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
191 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
192 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
193 aio_mlockall $flags, $callback->($status)
194 aio_group $callback->(...)
195 aio_nop $callback->()
196
197 $prev_pri = aioreq_pri [$pri]
198 aioreq_nice $pri_adjust
199
200 IO::AIO::poll_wait
201 IO::AIO::poll_cb
202 IO::AIO::poll
203 IO::AIO::flush
204 IO::AIO::max_poll_reqs $nreqs
205 IO::AIO::max_poll_time $seconds
206 IO::AIO::min_parallel $nthreads
207 IO::AIO::max_parallel $nthreads
208 IO::AIO::max_idle $nthreads
209 IO::AIO::idle_timeout $seconds
210 IO::AIO::max_outstanding $maxreqs
211 IO::AIO::nreqs
212 IO::AIO::nready
213 IO::AIO::npending
214
215 IO::AIO::sendfile $ofh, $ifh, $offset, $count
216 IO::AIO::fadvise $fh, $offset, $len, $advice
217 IO::AIO::madvise $scalar, $offset, $length, $advice
218 IO::AIO::mprotect $scalar, $offset, $length, $protect
219 IO::AIO::munlock $scalar, $offset = 0, $length = undef
220 IO::AIO::munlockall
221
173 AIO REQUEST FUNCTIONS 222 AIO REQUEST FUNCTIONS
174 All the "aio_*" calls are more or less thin wrappers around the syscall 223 All the "aio_*" calls are more or less thin wrappers around the syscall
175 with the same name (sans "aio_"). The arguments are similar or 224 with the same name (sans "aio_"). The arguments are similar or
176 identical, and they all accept an additional (and optional) $callback 225 identical, and they all accept an additional (and optional) $callback
177 argument which must be a code reference. This code reference will get 226 argument which must be a code reference. This code reference will get
… …
248 will be modified by the umask in effect then the request is being 297 will be modified by the umask in effect then the request is being
249 executed, so better never change the umask. 298 executed, so better never change the umask.
250 299
251 Example: 300 Example:
252 301
253 aio_open "/etc/passwd", O_RDONLY, 0, sub { 302 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
254 if ($_[0]) { 303 if ($_[0]) {
255 print "open successful, fh is $_[0]\n"; 304 print "open successful, fh is $_[0]\n";
256 ... 305 ...
257 } else { 306 } else {
258 die "open failed: $!\n"; 307 die "open failed: $!\n";
259 } 308 }
260 }; 309 };
261 310
311 In addition to all the common open modes/flags ("O_RDONLY",
312 "O_WRONLY", "O_RDWR", "O_CREAT", "O_TRUNC", "O_EXCL" and
313 "O_APPEND"), the following POSIX and non-POSIX constants are
314 available (missing ones on your system are, as usual, 0):
315
316 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
317 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
318 "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT".
319
262 aio_close $fh, $callback->($status) 320 aio_close $fh, $callback->($status)
263 Asynchronously close a file and call the callback with the result 321 Asynchronously close a file and call the callback with the result
264 code. 322 code.
265 323
266 Unfortunately, you can't do this to perl. Perl *insists* very 324 Unfortunately, you can't do this to perl. Perl *insists* very
… …
311 reading at byte offset $in_offset, and starts writing at the current 369 reading at byte offset $in_offset, and starts writing at the current
312 file offset of $out_fh. Because of that, it is not safe to issue 370 file offset of $out_fh. Because of that, it is not safe to issue
313 more than one "aio_sendfile" per $out_fh, as they will interfere 371 more than one "aio_sendfile" per $out_fh, as they will interfere
314 with each other. 372 with each other.
315 373
374 Please note that "aio_sendfile" can read more bytes from $in_fh than
375 are written, and there is no way to find out how many bytes have
376 been read from "aio_sendfile" alone, as "aio_sendfile" only provides
377 the number of bytes written to $out_fh. Only if the result value
378 equals $length one can assume that $length bytes have been read.
379
380 Unlike with other "aio_" functions, it makes a lot of sense to use
381 "aio_sendfile" on non-blocking sockets, as long as one end
382 (typically the $in_fh) is a file - the file I/O will then be
383 asynchronous, while the socket I/O will be non-blocking. Note,
384 however, that you can run into a trap where "aio_sendfile" reads
385 some data with readahead, then fails to write all data, and when the
386 socket is ready the next time, the data in the cache is already
387 lost, forcing "aio_sendfile" to again hit the disk. Explicit
388 "aio_read" + "aio_write" let's you control resource usage much
389 better.
390
316 This call tries to make use of a native "sendfile" syscall to 391 This call tries to make use of a native "sendfile" syscall to
317 provide zero-copy operation. For this to work, $out_fh should refer 392 provide zero-copy operation. For this to work, $out_fh should refer
318 to a socket, and $in_fh should refer to mmap'able file. 393 to a socket, and $in_fh should refer to an mmap'able file.
319 394
320 If the native sendfile call fails or is not implemented, it will be 395 If a native sendfile cannot be found or it fails with "ENOSYS",
396 "ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK",
321 emulated, so you can call "aio_sendfile" on any type of filehandle 397 it will be emulated, so you can call "aio_sendfile" on any type of
322 regardless of the limitations of the operating system. 398 filehandle regardless of the limitations of the operating system.
323
324 Please note, however, that "aio_sendfile" can read more bytes from
325 $in_fh than are written, and there is no way to find out how many
326 bytes have been read from "aio_sendfile" alone, as "aio_sendfile"
327 only provides the number of bytes written to $out_fh. Only if the
328 result value equals $length one can assume that $length bytes have
329 been read.
330 399
331 aio_readahead $fh,$offset,$length, $callback->($retval) 400 aio_readahead $fh,$offset,$length, $callback->($retval)
332 "aio_readahead" populates the page cache with data from a file so 401 "aio_readahead" populates the page cache with data from a file so
333 that subsequent reads from that file will not block on disk I/O. The 402 that subsequent reads from that file will not block on disk I/O. The
334 $offset argument specifies the starting point from which data is to 403 $offset argument specifies the starting point from which data is to
… …
355 Currently, the stats are always 64-bit-stats, i.e. instead of 424 Currently, the stats are always 64-bit-stats, i.e. instead of
356 returning an error when stat'ing a large file, the results will be 425 returning an error when stat'ing a large file, the results will be
357 silently truncated unless perl itself is compiled with large file 426 silently truncated unless perl itself is compiled with large file
358 support. 427 support.
359 428
429 To help interpret the mode and dev/rdev stat values, IO::AIO offers
430 the following constants and functions (if not implemented, the
431 constants will be 0 and the functions will either "croak" or fall
432 back on traditional behaviour).
433
434 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
435 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
436 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
437
360 Example: Print the length of /etc/passwd: 438 Example: Print the length of /etc/passwd:
361 439
362 aio_stat "/etc/passwd", sub { 440 aio_stat "/etc/passwd", sub {
363 $_[0] and die "stat failed: $!"; 441 $_[0] and die "stat failed: $!";
364 print "size is ", -s _, "\n"; 442 print "size is ", -s _, "\n";
365 }; 443 };
366 444
445 aio_statvfs $fh_or_path, $callback->($statvfs)
446 Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on
447 whether a file handle or path was passed.
448
449 On success, the callback is passed a hash reference with the
450 following members: "bsize", "frsize", "blocks", "bfree", "bavail",
451 "files", "ffree", "favail", "fsid", "flag" and "namemax". On
452 failure, "undef" is passed.
453
454 The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY"
455 and "ST_NOSUID".
456
457 The following non-POSIX IO::AIO::ST_* flag masks are defined to
458 their correct value when available, or to 0 on systems that do not
459 support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS",
460 "ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE",
461 "ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME".
462
463 Example: stat "/wd" and dump out the data if successful.
464
465 aio_statvfs "/wd", sub {
466 my $f = $_[0]
467 or die "statvfs: $!";
468
469 use Data::Dumper;
470 say Dumper $f;
471 };
472
473 # result:
474 {
475 bsize => 1024,
476 bfree => 4333064312,
477 blocks => 10253828096,
478 files => 2050765568,
479 flag => 4096,
480 favail => 2042092649,
481 bavail => 4333064312,
482 ffree => 2042092649,
483 namemax => 255,
484 frsize => 1024,
485 fsid => 1810
486 }
487
367 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 488 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
368 Works like perl's "utime" function (including the special case of 489 Works like perl's "utime" function (including the special case of
369 $atime and $mtime being undef). Fractional times are supported if 490 $atime and $mtime being undef). Fractional times are supported if
370 the underlying syscalls support them. 491 the underlying syscalls support them.
371 492
… …
409 530
410 The only (POSIX-) portable way of calling this function is: 531 The only (POSIX-) portable way of calling this function is:
411 532
412 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 533 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
413 534
535 See "aio_stat" for info about some potentially helpful extra
536 constants and functions.
537
414 aio_link $srcpath, $dstpath, $callback->($status) 538 aio_link $srcpath, $dstpath, $callback->($status)
415 Asynchronously create a new link to the existing object at $srcpath 539 Asynchronously create a new link to the existing object at $srcpath
416 at the path $dstpath and call the callback with the result code. 540 at the path $dstpath and call the callback with the result code.
417 541
418 aio_symlink $srcpath, $dstpath, $callback->($status) 542 aio_symlink $srcpath, $dstpath, $callback->($status)
… …
454 The flags are a combination of the following constants, ORed 578 The flags are a combination of the following constants, ORed
455 together (the flags will also be passed to the callback, possibly 579 together (the flags will also be passed to the callback, possibly
456 modified): 580 modified):
457 581
458 IO::AIO::READDIR_DENTS 582 IO::AIO::READDIR_DENTS
459 When this flag is off, then the callback gets an arrayref with 583 When this flag is off, then the callback gets an arrayref
460 of names only (as with "aio_readdir"), otherwise it gets an 584 consisting of names only (as with "aio_readdir"), otherwise it
461 arrayref with "[$name, $type, $inode]" arrayrefs, each 585 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
462 describing a single directory entry in more detail. 586 describing a single directory entry in more detail.
463 587
464 $name is the name of the entry. 588 $name is the name of the entry.
465 589
466 $type is one of the "IO::AIO::DT_xxx" constants: 590 $type is one of the "IO::AIO::DT_xxx" constants:
… …
479 unspecified content on systems that do not deliver the inode 603 unspecified content on systems that do not deliver the inode
480 information. 604 information.
481 605
482 IO::AIO::READDIR_DIRS_FIRST 606 IO::AIO::READDIR_DIRS_FIRST
483 When this flag is set, then the names will be returned in an 607 When this flag is set, then the names will be returned in an
484 order where likely directories come first. This is useful when 608 order where likely directories come first, in optimal stat
485 you need to quickly find directories, or you want to find all 609 order. This is useful when you need to quickly find directories,
486 directories while avoiding to stat() each entry. 610 or you want to find all directories while avoiding to stat()
611 each entry.
487 612
488 If the system returns type information in readdir, then this is 613 If the system returns type information in readdir, then this is
489 used to find directories directly. Otherwise, likely directories 614 used to find directories directly. Otherwise, likely directories
490 are files beginning with ".", or otherwise files with no dots, 615 are names beginning with ".", or otherwise names with no dots,
491 of which files with short names are tried first. 616 of which names with short names are tried first.
492 617
493 IO::AIO::READDIR_STAT_ORDER 618 IO::AIO::READDIR_STAT_ORDER
494 When this flag is set, then the names will be returned in an 619 When this flag is set, then the names will be returned in an
495 order suitable for stat()'ing each one. That is, when you plan 620 order suitable for stat()'ing each one. That is, when you plan
496 to stat() all files in the given directory, then the returned 621 to stat() all files in the given directory, then the returned
… …
512 into memory. Status is the same as with aio_read. 637 into memory. Status is the same as with aio_read.
513 638
514 aio_copy $srcpath, $dstpath, $callback->($status) 639 aio_copy $srcpath, $dstpath, $callback->($status)
515 Try to copy the *file* (directories not supported as either source 640 Try to copy the *file* (directories not supported as either source
516 or destination) from $srcpath to $dstpath and call the callback with 641 or destination) from $srcpath to $dstpath and call the callback with
517 the 0 (error) or -1 ok. 642 a status of 0 (ok) or -1 (error, see $!).
518 643
519 This is a composite request that creates the destination file with 644 This is a composite request that creates the destination file with
520 mode 0200 and copies the contents of the source file into it using 645 mode 0200 and copies the contents of the source file into it using
521 "aio_sendfile", followed by restoring atime, mtime, access mode and 646 "aio_sendfile", followed by restoring atime, mtime, access mode and
522 uid/gid, in that order. 647 uid/gid, in that order.
… …
526 uid/gid, where errors are being ignored. 651 uid/gid, where errors are being ignored.
527 652
528 aio_move $srcpath, $dstpath, $callback->($status) 653 aio_move $srcpath, $dstpath, $callback->($status)
529 Try to move the *file* (directories not supported as either source 654 Try to move the *file* (directories not supported as either source
530 or destination) from $srcpath to $dstpath and call the callback with 655 or destination) from $srcpath to $dstpath and call the callback with
531 the 0 (error) or -1 ok. 656 a status of 0 (ok) or -1 (error, see $!).
532 657
533 This is a composite request that tries to rename(2) the file first; 658 This is a composite request that tries to rename(2) the file first;
534 if rename fails with "EXDEV", it copies the file with "aio_copy" 659 if rename fails with "EXDEV", it copies the file with "aio_copy"
535 and, if that is successful, unlinks the $srcpath. 660 and, if that is successful, unlinks the $srcpath.
536 661
… …
636 Future versions of this function might fall back to other methods 761 Future versions of this function might fall back to other methods
637 when "fsync" on the directory fails (such as calling "sync"). 762 when "fsync" on the directory fails (such as calling "sync").
638 763
639 Passes 0 when everything went ok, and -1 on error. 764 Passes 0 when everything went ok, and -1 on error.
640 765
766 aio_msync $scalar, $offset = 0, $length = undef, flags = 0,
767 $callback->($status)
768 This is a rather advanced IO::AIO call, which only works on
769 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
770 also works on data scalars managed by the Sys::Mmap or Mmap modules,
771 note that the scalar must only be modified in-place while an aio
772 operation is pending on it).
773
774 It calls the "msync" function of your OS, if available, with the
775 memory area starting at $offset in the string and ending $length
776 bytes later. If $length is negative, counts from the end, and if
777 $length is "undef", then it goes till the end of the string. The
778 flags can be a combination of "IO::AIO::MS_ASYNC",
779 "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC".
780
781 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
782 $callback->($status)
783 This is a rather advanced IO::AIO call, which works best on
784 mmap(2)ed scalars.
785
786 It touches (reads or writes) all memory pages in the specified range
787 inside the scalar. All caveats and parameters are the same as for
788 "aio_msync", above, except for flags, which must be either 0 (which
789 reads all pages and ensures they are instantiated) or
790 "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading
791 and writing an octet from it, which dirties the page).
792
793 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
794 This is a rather advanced IO::AIO call, which works best on
795 mmap(2)ed scalars.
796
797 It reads in all the pages of the underlying storage into memory (if
798 any) and locks them, so they are not getting swapped/paged out or
799 removed.
800
801 If $length is undefined, then the scalar will be locked till the
802 end.
803
804 On systems that do not implement "mlock", this function returns -1
805 and sets errno to "ENOSYS".
806
807 Note that the corresponding "munlock" is synchronous and is
808 documented under "MISCELLANEOUS FUNCTIONS".
809
810 Example: open a file, mmap and mlock it - both will be undone when
811 $data gets destroyed.
812
813 open my $fh, "<", $path or die "$path: $!";
814 my $data;
815 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
816 aio_mlock $data; # mlock in background
817
818 aio_mlockall $flags, $callback->($status)
819 Calls the "mlockall" function with the given $flags (a combination
820 of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE").
821
822 On systems that do not implement "mlockall", this function returns
823 -1 and sets errno to "ENOSYS".
824
825 Note that the corresponding "munlockall" is synchronous and is
826 documented under "MISCELLANEOUS FUNCTIONS".
827
828 Example: asynchronously lock all current and future pages into
829 memory.
830
831 aio_mlockall IO::AIO::MCL_FUTURE;
832
641 aio_group $callback->(...) 833 aio_group $callback->(...)
642 This is a very special aio request: Instead of doing something, it 834 This is a very special aio request: Instead of doing something, it
643 is a container for other aio requests, which is useful if you want 835 is a container for other aio requests, which is useful if you want
644 to bundle many requests into a single, composite, request with a 836 to bundle many requests into a single, composite, request with a
645 definite callback and the ability to cancel the whole request with 837 definite callback and the ability to cancel the whole request with
… …
760 952
761 $grp->cancel_subs 953 $grp->cancel_subs
762 Cancel all subrequests and clears any feeder, but not the group 954 Cancel all subrequests and clears any feeder, but not the group
763 request itself. Useful when you queued a lot of events but got a 955 request itself. Useful when you queued a lot of events but got a
764 result early. 956 result early.
957
958 The group request will finish normally (you cannot add requests to
959 the group).
765 960
766 $grp->result (...) 961 $grp->result (...)
767 Set the result value(s) that will be passed to the group callback 962 Set the result value(s) that will be passed to the group callback
768 when all subrequests have finished and set the groups errno to the 963 when all subrequests have finished and set the groups errno to the
769 current value of errno (just like calling "errno" without an error 964 current value of errno (just like calling "errno" without an error
… …
837 1032
838 See "poll_cb" for an example. 1033 See "poll_cb" for an example.
839 1034
840 IO::AIO::poll_cb 1035 IO::AIO::poll_cb
841 Process some outstanding events on the result pipe. You have to call 1036 Process some outstanding events on the result pipe. You have to call
842 this regularly. Returns 0 if all events could be processed, or -1 if 1037 this regularly. Returns 0 if all events could be processed (or there
843 it returned earlier for whatever reason. Returns immediately when no 1038 were no events to process), or -1 if it returned earlier for
844 events are outstanding. The amount of events processed depends on 1039 whatever reason. Returns immediately when no events are outstanding.
845 the settings of "IO::AIO::max_poll_req" and 1040 The amount of events processed depends on the settings of
846 "IO::AIO::max_poll_time". 1041 "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time".
847 1042
848 If not all requests were processed for whatever reason, the 1043 If not all requests were processed for whatever reason, the
849 filehandle will still be ready when "poll_cb" returns, so normally 1044 filehandle will still be ready when "poll_cb" returns, so normally
850 you don't have to do anything special to have it called later. 1045 you don't have to do anything special to have it called later.
851 1046
1047 Apart from calling "IO::AIO::poll_cb" when the event filehandle
1048 becomes ready, it can be beneficial to call this function from loops
1049 which submit a lot of requests, to make sure the results get
1050 processed when they become available and not just when the loop is
1051 finished and the event loop takes over again. This function returns
1052 very fast when there are no outstanding requests.
1053
852 Example: Install an Event watcher that automatically calls 1054 Example: Install an Event watcher that automatically calls
853 IO::AIO::poll_cb with high priority (more examples can be found in 1055 IO::AIO::poll_cb with high priority (more examples can be found in
854 the SYNOPSIS section, at the top of this document): 1056 the SYNOPSIS section, at the top of this document):
855 1057
856 Event->io (fd => IO::AIO::poll_fileno, 1058 Event->io (fd => IO::AIO::poll_fileno,
857 poll => 'r', async => 1, 1059 poll => 'r', async => 1,
858 cb => \&IO::AIO::poll_cb); 1060 cb => \&IO::AIO::poll_cb);
1061
1062 IO::AIO::poll_wait
1063 If there are any outstanding requests and none of them in the result
1064 phase, wait till the result filehandle becomes ready for reading
1065 (simply does a "select" on the filehandle. This is useful if you
1066 want to synchronously wait for some requests to finish).
1067
1068 See "nreqs" for an example.
1069
1070 IO::AIO::poll
1071 Waits until some requests have been handled.
1072
1073 Returns the number of requests processed, but is otherwise strictly
1074 equivalent to:
1075
1076 IO::AIO::poll_wait, IO::AIO::poll_cb
1077
1078 IO::AIO::flush
1079 Wait till all outstanding AIO requests have been handled.
1080
1081 Strictly equivalent to:
1082
1083 IO::AIO::poll_wait, IO::AIO::poll_cb
1084 while IO::AIO::nreqs;
859 1085
860 IO::AIO::max_poll_reqs $nreqs 1086 IO::AIO::max_poll_reqs $nreqs
861 IO::AIO::max_poll_time $seconds 1087 IO::AIO::max_poll_time $seconds
862 These set the maximum number of requests (default 0, meaning 1088 These set the maximum number of requests (default 0, meaning
863 infinity) that are being processed by "IO::AIO::poll_cb" in one 1089 infinity) that are being processed by "IO::AIO::poll_cb" in one
… …
887 # use a low priority so other tasks have priority 1113 # use a low priority so other tasks have priority
888 Event->io (fd => IO::AIO::poll_fileno, 1114 Event->io (fd => IO::AIO::poll_fileno,
889 poll => 'r', nice => 1, 1115 poll => 'r', nice => 1,
890 cb => &IO::AIO::poll_cb); 1116 cb => &IO::AIO::poll_cb);
891 1117
892 IO::AIO::poll_wait
893 If there are any outstanding requests and none of them in the result
894 phase, wait till the result filehandle becomes ready for reading
895 (simply does a "select" on the filehandle. This is useful if you
896 want to synchronously wait for some requests to finish).
897
898 See "nreqs" for an example.
899
900 IO::AIO::poll
901 Waits until some requests have been handled.
902
903 Returns the number of requests processed, but is otherwise strictly
904 equivalent to:
905
906 IO::AIO::poll_wait, IO::AIO::poll_cb
907
908 IO::AIO::flush
909 Wait till all outstanding AIO requests have been handled.
910
911 Strictly equivalent to:
912
913 IO::AIO::poll_wait, IO::AIO::poll_cb
914 while IO::AIO::nreqs;
915
916 CONTROLLING THE NUMBER OF THREADS 1118 CONTROLLING THE NUMBER OF THREADS
917 IO::AIO::min_parallel $nthreads 1119 IO::AIO::min_parallel $nthreads
918 Set the minimum number of AIO threads to $nthreads. The current 1120 Set the minimum number of AIO threads to $nthreads. The current
919 default is 8, which means eight asynchronous operations can execute 1121 default is 8, which means eight asynchronous operations can execute
920 concurrently at any one time (the number of outstanding requests, 1122 concurrently at any one time (the number of outstanding requests,
… …
949 1151
950 Under normal circumstances you don't need to call this function. 1152 Under normal circumstances you don't need to call this function.
951 1153
952 IO::AIO::max_idle $nthreads 1154 IO::AIO::max_idle $nthreads
953 Limit the number of threads (default: 4) that are allowed to idle 1155 Limit the number of threads (default: 4) that are allowed to idle
954 (i.e., threads that did not get a request to process within 10 1156 (i.e., threads that did not get a request to process within the idle
955 seconds). That means if a thread becomes idle while $nthreads other 1157 timeout (default: 10 seconds). That means if a thread becomes idle
956 threads are also idle, it will free its resources and exit. 1158 while $nthreads other threads are also idle, it will free its
1159 resources and exit.
957 1160
958 This is useful when you allow a large number of threads (e.g. 100 or 1161 This is useful when you allow a large number of threads (e.g. 100 or
959 1000) to allow for extremely high load situations, but want to free 1162 1000) to allow for extremely high load situations, but want to free
960 resources under normal circumstances (1000 threads can easily 1163 resources under normal circumstances (1000 threads can easily
961 consume 30MB of RAM). 1164 consume 30MB of RAM).
962 1165
963 The default is probably ok in most situations, especially if thread 1166 The default is probably ok in most situations, especially if thread
964 creation is fast. If thread creation is very slow on your system you 1167 creation is fast. If thread creation is very slow on your system you
965 might want to use larger values. 1168 might want to use larger values.
1169
1170 IO::AIO::idle_timeout $seconds
1171 Sets the minimum idle timeout (default 10) after which worker
1172 threads are allowed to exit. SEe "IO::AIO::max_idle".
966 1173
967 IO::AIO::max_outstanding $maxreqs 1174 IO::AIO::max_outstanding $maxreqs
968 This is a very bad function to use in interactive programs because 1175 This is a very bad function to use in interactive programs because
969 it blocks, and a bad way to reduce concurrency because it is 1176 it blocks, and a bad way to reduce concurrency because it is
970 inexact: Better use an "aio_group" together with a feed callback. 1177 inexact: Better use an "aio_group" together with a feed callback.
… …
1012 set to non-blocking operations). 1219 set to non-blocking operations).
1013 1220
1014 Returns the number of bytes copied, or -1 on error. 1221 Returns the number of bytes copied, or -1 on error.
1015 1222
1016 IO::AIO::fadvise $fh, $offset, $len, $advice 1223 IO::AIO::fadvise $fh, $offset, $len, $advice
1017 Simply calls the "posix_fadvise" function (see it's manpage for 1224 Simply calls the "posix_fadvise" function (see its manpage for
1018 details). The following advice constants are avaiable: 1225 details). The following advice constants are avaiable:
1019 "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", 1226 "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL",
1020 "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", 1227 "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE",
1021 "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". 1228 "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED".
1022 1229
1023 On systems that do not implement "posix_fadvise", this function 1230 On systems that do not implement "posix_fadvise", this function
1024 returns ENOSYS, otherwise the return value of "posix_fadvise". 1231 returns ENOSYS, otherwise the return value of "posix_fadvise".
1232
1233 IO::AIO::madvise $scalar, $offset, $len, $advice
1234 Simply calls the "posix_madvise" function (see its manpage for
1235 details). The following advice constants are avaiable:
1236 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1237 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1238 "IO::AIO::MADV_DONTNEED".
1239
1240 On systems that do not implement "posix_madvise", this function
1241 returns ENOSYS, otherwise the return value of "posix_madvise".
1242
1243 IO::AIO::mprotect $scalar, $offset, $len, $protect
1244 Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1245 $scalar (see its manpage for details). The following protect
1246 constants are avaiable: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1247 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1248
1249 On systems that do not implement "mprotect", this function returns
1250 ENOSYS, otherwise the return value of "mprotect".
1251
1252 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1253 Memory-maps a file (or anonymous memory range) and attaches it to
1254 the given $scalar, which will act like a string scalar.
1255
1256 The only operations allowed on the scalar are "substr"/"vec" that
1257 don't change the string length, and most read-only operations such
1258 as copying it or searching it with regexes and so on.
1259
1260 Anything else is unsafe and will, at best, result in memory leaks.
1261
1262 The memory map associated with the $scalar is automatically removed
1263 when the $scalar is destroyed, or when the "IO::AIO::mmap" or
1264 "IO::AIO::munmap" functions are called.
1265
1266 This calls the "mmap"(2) function internally. See your system's
1267 manual page for details on the $length, $prot and $flags parameters.
1268
1269 The $length must be larger than zero and smaller than the actual
1270 filesize.
1271
1272 $prot is a combination of "IO::AIO::PROT_NONE",
1273 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1274 "IO::AIO::PROT_WRITE",
1275
1276 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1277 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1278 not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS"
1279 (which is set to "MAP_ANON" if your system only provides this
1280 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
1281 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or
1282 "IO::AIO::MAP_NONBLOCK"
1283
1284 If $fh is "undef", then a file descriptor of -1 is passed.
1285
1286 $offset is the offset from the start of the file - it generally must
1287 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
1288
1289 Example:
1290
1291 use Digest::MD5;
1292 use IO::AIO;
1293
1294 open my $fh, "<verybigfile"
1295 or die "$!";
1296
1297 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1298 or die "verybigfile: $!";
1299
1300 my $fast_md5 = md5 $data;
1301
1302 IO::AIO::munmap $scalar
1303 Removes a previous mmap and undefines the $scalar.
1304
1305 IO::AIO::munlock $scalar, $offset = 0, $length = undef
1306 Calls the "munlock" function, undoing the effects of a previous
1307 "aio_mlock" call (see its description for details).
1308
1309 IO::AIO::munlockall
1310 Calls the "munlockall" function.
1311
1312 On systems that do not implement "munlockall", this function returns
1313 ENOSYS, otherwise the return value of "munlockall".
1314
1315EVENT LOOP INTEGRATION
1316 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1317 automatically into many event loops:
1318
1319 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1320 use AnyEvent::AIO;
1321
1322 You can also integrate IO::AIO manually into many event loops, here are
1323 some examples of how to do this:
1324
1325 # EV integration
1326 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1327
1328 # Event integration
1329 Event->io (fd => IO::AIO::poll_fileno,
1330 poll => 'r',
1331 cb => \&IO::AIO::poll_cb);
1332
1333 # Glib/Gtk2 integration
1334 add_watch Glib::IO IO::AIO::poll_fileno,
1335 in => sub { IO::AIO::poll_cb; 1 };
1336
1337 # Tk integration
1338 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1339 readable => \&IO::AIO::poll_cb);
1340
1341 # Danga::Socket integration
1342 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1343 \&IO::AIO::poll_cb);
1025 1344
1026 FORK BEHAVIOUR 1345 FORK BEHAVIOUR
1027 This module should do "the right thing" when the process using it forks: 1346 This module should do "the right thing" when the process using it forks:
1028 1347
1029 Before the fork, IO::AIO enters a quiescent state where no requests can 1348 Before the fork, IO::AIO enters a quiescent state where no requests can

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines