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Revision 1.21 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.30 by root, Sat May 10 22:58:16 2008 UTC

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 28
29 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
30 use AnyEvent::AIO;
31
29 # AnyEvent integration 32 # EV integration
30 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 33 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
31 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
32 34
33 # Event integration 35 # Event integration
34 Event->io (fd => IO::AIO::poll_fileno, 36 Event->io (fd => IO::AIO::poll_fileno,
35 poll => 'r', 37 poll => 'r',
36 cb => \&IO::AIO::poll_cb); 38 cb => \&IO::AIO::poll_cb);
61 faster on a RAID volume or over NFS when you do a number of stat 63 faster on a RAID volume or over NFS when you do a number of stat
62 operations concurrently. 64 operations concurrently.
63 65
64 While most of this works on all types of file descriptors (for example 66 While most of this works on all types of file descriptors (for example
65 sockets), using these functions on file descriptors that support 67 sockets), using these functions on file descriptors that support
66 nonblocking operation (again, sockets, pipes etc.) is very inefficient 68 nonblocking operation (again, sockets, pipes etc.) is very inefficient.
67 or might not work (aio_read fails on sockets/pipes/fifos). Use an event
68 loop for that (such as the Event module): IO::AIO will naturally fit 69 Use an event loop for that (such as the Event module): IO::AIO will
69 into such an event loop itself. 70 naturally fit into such an event loop itself.
70 71
71 In this version, a number of threads are started that execute your 72 In this version, a number of threads are started that execute your
72 requests and signal their completion. You don't need thread support in 73 requests and signal their completion. You don't need thread support in
73 perl, and the threads created by this module will not be visible to 74 perl, and the threads created by this module will not be visible to
74 perl. In the future, this module might make use of the native aio 75 perl. In the future, this module might make use of the native aio
76 not well-supported or restricted (GNU/Linux doesn't allow them on normal 77 not well-supported or restricted (GNU/Linux doesn't allow them on normal
77 files currently, for example), and they would only support aio_read and 78 files currently, for example), and they would only support aio_read and
78 aio_write, so the remaining functionality would have to be implemented 79 aio_write, so the remaining functionality would have to be implemented
79 using threads anyway. 80 using threads anyway.
80 81
81 Although the module will work with in the presence of other (Perl-) 82 Although the module will work in the presence of other (Perl-) threads,
82 threads, it is currently not reentrant in any way, so use appropriate 83 it is currently not reentrant in any way, so use appropriate locking
83 locking yourself, always call "poll_cb" from within the same thread, or 84 yourself, always call "poll_cb" from within the same thread, or never
84 never call "poll_cb" (or other "aio_" functions) recursively. 85 call "poll_cb" (or other "aio_" functions) recursively.
85 86
86 EXAMPLE 87 EXAMPLE
87 This is a simple example that uses the Event module and loads 88 This is a simple example that uses the Event module and loads
88 /etc/passwd asynchronously: 89 /etc/passwd asynchronously:
89 90
242 They are the same as used by "sysopen". 243 They are the same as used by "sysopen".
243 244
244 Likewise, $mode specifies the mode of the newly created file, if it 245 Likewise, $mode specifies the mode of the newly created file, if it
245 didn't exist and "O_CREAT" has been given, just like perl's 246 didn't exist and "O_CREAT" has been given, just like perl's
246 "sysopen", except that it is mandatory (i.e. use 0 if you don't 247 "sysopen", except that it is mandatory (i.e. use 0 if you don't
247 create new files, and 0666 or 0777 if you do). 248 create new files, and 0666 or 0777 if you do). Note that the $mode
249 will be modified by the umask in effect then the request is being
250 executed, so better never change the umask.
248 251
249 Example: 252 Example:
250 253
251 aio_open "/etc/passwd", O_RDONLY, 0, sub { 254 aio_open "/etc/passwd", O_RDONLY, 0, sub {
252 if ($_[0]) { 255 if ($_[0]) {
257 } 260 }
258 }; 261 };
259 262
260 aio_close $fh, $callback->($status) 263 aio_close $fh, $callback->($status)
261 Asynchronously close a file and call the callback with the result 264 Asynchronously close a file and call the callback with the result
262 code. *WARNING:* although accepted, you should not pass in a perl 265 code.
263 filehandle here, as perl will likely close the file descriptor
264 another time when the filehandle is destroyed. Normally, you can
265 safely call perls "close" or just let filehandles go out of scope.
266 266
267 This is supposed to be a bug in the API, so that might change. It's 267 Unfortunately, you can't do this to perl. Perl *insists* very
268 therefore best to avoid this function. 268 strongly on closing the file descriptor associated with the
269 filehandle itself.
270
271 Therefore, "aio_close" will not close the filehandle - instead it
272 will use dup2 to overwrite the file descriptor with the write-end of
273 a pipe (the pipe fd will be created on demand and will be cached).
274
275 Or in other words: the file descriptor will be closed, but it will
276 not be free for reuse until the perl filehandle is closed.
269 277
270 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 278 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
271 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 279 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
272 Reads or writes "length" bytes from the specified "fh" and "offset" 280 Reads or writes $length bytes from the specified $fh and $offset
273 into the scalar given by "data" and offset "dataoffset" and calls 281 into the scalar given by $data and offset $dataoffset and calls the
274 the callback without the actual number of bytes read (or -1 on 282 callback without the actual number of bytes read (or -1 on error,
275 error, just like the syscall). 283 just like the syscall).
284
285 If $offset is undefined, then the current file descriptor offset
286 will be used (and updated), otherwise the file descriptor offset
287 will not be changed by these calls.
288
289 If $length is undefined in "aio_write", use the remaining length of
290 $data.
291
292 If $dataoffset is less than zero, it will be counted from the end of
293 $data.
276 294
277 The $data scalar *MUST NOT* be modified in any way while the request 295 The $data scalar *MUST NOT* be modified in any way while the request
278 is outstanding. Modifying it can result in segfaults or WW3 (if the 296 is outstanding. Modifying it can result in segfaults or World War
279 necessary/optional hardware is installed). 297 III (if the necessary/optional hardware is installed).
280 298
281 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at 299 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at
282 offset 0 within the scalar: 300 offset 0 within the scalar:
283 301
284 aio_read $fh, 7, 15, $buffer, 0, sub { 302 aio_read $fh, 7, 15, $buffer, 0, sub {
342 aio_stat "/etc/passwd", sub { 360 aio_stat "/etc/passwd", sub {
343 $_[0] and die "stat failed: $!"; 361 $_[0] and die "stat failed: $!";
344 print "size is ", -s _, "\n"; 362 print "size is ", -s _, "\n";
345 }; 363 };
346 364
365 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
366 Works like perl's "utime" function (including the special case of
367 $atime and $mtime being undef). Fractional times are supported if
368 the underlying syscalls support them.
369
370 When called with a pathname, uses utimes(2) if available, otherwise
371 utime(2). If called on a file descriptor, uses futimes(2) if
372 available, otherwise returns ENOSYS, so this is not portable.
373
374 Examples:
375
376 # set atime and mtime to current time (basically touch(1)):
377 aio_utime "path", undef, undef;
378 # set atime to current time and mtime to beginning of the epoch:
379 aio_utime "path", time, undef; # undef==0
380
381 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
382 Works like perl's "chown" function, except that "undef" for either
383 $uid or $gid is being interpreted as "do not change" (but -1 can
384 also be used).
385
386 Examples:
387
388 # same as "chown root path" in the shell:
389 aio_chown "path", 0, -1;
390 # same as above:
391 aio_chown "path", 0, undef;
392
393 aio_truncate $fh_or_path, $offset, $callback->($status)
394 Works like truncate(2) or ftruncate(2).
395
396 aio_chmod $fh_or_path, $mode, $callback->($status)
397 Works like perl's "chmod" function.
398
347 aio_unlink $pathname, $callback->($status) 399 aio_unlink $pathname, $callback->($status)
348 Asynchronously unlink (delete) a file and call the callback with the 400 Asynchronously unlink (delete) a file and call the callback with the
349 result code. 401 result code.
350 402
351 aio_mknod $path, $mode, $dev, $callback->($status) 403 aio_mknod $path, $mode, $dev, $callback->($status)
373 425
374 aio_rename $srcpath, $dstpath, $callback->($status) 426 aio_rename $srcpath, $dstpath, $callback->($status)
375 Asynchronously rename the object at $srcpath to $dstpath, just as 427 Asynchronously rename the object at $srcpath to $dstpath, just as
376 rename(2) and call the callback with the result code. 428 rename(2) and call the callback with the result code.
377 429
430 aio_mkdir $pathname, $mode, $callback->($status)
431 Asynchronously mkdir (create) a directory and call the callback with
432 the result code. $mode will be modified by the umask at the time the
433 request is executed, so do not change your umask.
434
378 aio_rmdir $pathname, $callback->($status) 435 aio_rmdir $pathname, $callback->($status)
379 Asynchronously rmdir (delete) a directory and call the callback with 436 Asynchronously rmdir (delete) a directory and call the callback with
380 the result code. 437 the result code.
381 438
382 aio_readdir $pathname, $callback->($entries) 439 aio_readdir $pathname, $callback->($entries)
384 entire directory (i.e. opendir + readdir + closedir). The entries 441 entire directory (i.e. opendir + readdir + closedir). The entries
385 will not be sorted, and will NOT include the "." and ".." entries. 442 will not be sorted, and will NOT include the "." and ".." entries.
386 443
387 The callback a single argument which is either "undef" or an 444 The callback a single argument which is either "undef" or an
388 array-ref with the filenames. 445 array-ref with the filenames.
446
447 aio_load $path, $data, $callback->($status)
448 This is a composite request that tries to fully load the given file
449 into memory. Status is the same as with aio_read.
389 450
390 aio_copy $srcpath, $dstpath, $callback->($status) 451 aio_copy $srcpath, $dstpath, $callback->($status)
391 Try to copy the *file* (directories not supported as either source 452 Try to copy the *file* (directories not supported as either source
392 or destination) from $srcpath to $dstpath and call the callback with 453 or destination) from $srcpath to $dstpath and call the callback with
393 the 0 (error) or -1 ok. 454 the 0 (error) or -1 ok.
461 522
462 It will also likely work on non-POSIX filesystems with reduced 523 It will also likely work on non-POSIX filesystems with reduced
463 efficiency as those tend to return 0 or 1 as link counts, which 524 efficiency as those tend to return 0 or 1 as link counts, which
464 disables the directory counting heuristic. 525 disables the directory counting heuristic.
465 526
527 aio_rmtree $path, $callback->($status)
528 Delete a directory tree starting (and including) $path, return the
529 status of the final "rmdir" only. This is a composite request that
530 uses "aio_scandir" to recurse into and rmdir directories, and unlink
531 everything else.
532
533 aio_sync $callback->($status)
534 Asynchronously call sync and call the callback when finished.
535
466 aio_fsync $fh, $callback->($status) 536 aio_fsync $fh, $callback->($status)
467 Asynchronously call fsync on the given filehandle and call the 537 Asynchronously call fsync on the given filehandle and call the
468 callback with the fsync result code. 538 callback with the fsync result code.
469 539
470 aio_fdatasync $fh, $callback->($status) 540 aio_fdatasync $fh, $callback->($status)
471 Asynchronously call fdatasync on the given filehandle and call the 541 Asynchronously call fdatasync on the given filehandle and call the
472 callback with the fdatasync result code. 542 callback with the fdatasync result code.
473 543
474 If this call isn't available because your OS lacks it or it couldn't 544 If this call isn't available because your OS lacks it or it couldn't
475 be detected, it will be emulated by calling "fsync" instead. 545 be detected, it will be emulated by calling "fsync" instead.
546
547 aio_pathsync $path, $callback->($status)
548 This request tries to open, fsync and close the given path. This is
549 a composite request intended tosync directories after directory
550 operations (E.g. rename). This might not work on all operating
551 systems or have any specific effect, but usually it makes sure that
552 directory changes get written to disc. It works for anything that
553 can be opened for read-only, not just directories.
554
555 Passes 0 when everything went ok, and -1 on error.
476 556
477 aio_group $callback->(...) 557 aio_group $callback->(...)
478 This is a very special aio request: Instead of doing something, it 558 This is a very special aio request: Instead of doing something, it
479 is a container for other aio requests, which is useful if you want 559 is a container for other aio requests, which is useful if you want
480 to bundle many requests into a single, composite, request with a 560 to bundle many requests into a single, composite, request with a
562 }; 642 };
563 643
564 This makes it very easy to create composite requests (see the source of 644 This makes it very easy to create composite requests (see the source of
565 "aio_move" for an application) that work and feel like simple requests. 645 "aio_move" for an application) that work and feel like simple requests.
566 646
567 * The IO::AIO::GRP objects will be cleaned up during calls to 647 * The IO::AIO::GRP objects will be cleaned up during calls to
568 "IO::AIO::poll_cb", just like any other request. 648 "IO::AIO::poll_cb", just like any other request.
649
569 * They can be canceled like any other request. Canceling will cancel not 650 * They can be canceled like any other request. Canceling will cancel
570 only the request itself, but also all requests it contains. 651 not only the request itself, but also all requests it contains.
652
571 * They can also can also be added to other IO::AIO::GRP objects. 653 * They can also can also be added to other IO::AIO::GRP objects.
654
572 * You must not add requests to a group from within the group callback 655 * You must not add requests to a group from within the group callback
573 (or any later time). 656 (or any later time).
574 657
575 Their lifetime, simplified, looks like this: when they are empty, they 658 Their lifetime, simplified, looks like this: when they are empty, they
576 will finish very quickly. If they contain only requests that are in the 659 will finish very quickly. If they contain only requests that are in the
577 "done" state, they will also finish. Otherwise they will continue to 660 "done" state, they will also finish. Otherwise they will continue to
578 exist. 661 exist.
595 request itself. Useful when you queued a lot of events but got a 678 request itself. Useful when you queued a lot of events but got a
596 result early. 679 result early.
597 680
598 $grp->result (...) 681 $grp->result (...)
599 Set the result value(s) that will be passed to the group callback 682 Set the result value(s) that will be passed to the group callback
600 when all subrequests have finished and set thre groups errno to the 683 when all subrequests have finished and set the groups errno to the
601 current value of errno (just like calling "errno" without an error 684 current value of errno (just like calling "errno" without an error
602 number). By default, no argument will be passed and errno is zero. 685 number). By default, no argument will be passed and errno is zero.
603 686
604 $grp->errno ([$errno]) 687 $grp->errno ([$errno])
605 Sets the group errno value to $errno, or the current value of errno 688 Sets the group errno value to $errno, or the current value of errno
786 869
787 The default is probably ok in most situations, especially if thread 870 The default is probably ok in most situations, especially if thread
788 creation is fast. If thread creation is very slow on your system you 871 creation is fast. If thread creation is very slow on your system you
789 might want to use larger values. 872 might want to use larger values.
790 873
791 $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 874 IO::AIO::max_outstanding $maxreqs
792 This is a very bad function to use in interactive programs because 875 This is a very bad function to use in interactive programs because
793 it blocks, and a bad way to reduce concurrency because it is 876 it blocks, and a bad way to reduce concurrency because it is
794 inexact: Better use an "aio_group" together with a feed callback. 877 inexact: Better use an "aio_group" together with a feed callback.
795 878
796 Sets the maximum number of outstanding requests to $nreqs. If you to 879 Sets the maximum number of outstanding requests to $nreqs. If you do
797 queue up more than this number of requests, the next call to the 880 queue up more than this number of requests, the next call to the
798 "poll_cb" (and "poll_some" and other functions calling "poll_cb") 881 "poll_cb" (and "poll_some" and other functions calling "poll_cb")
799 function will block until the limit is no longer exceeded. 882 function will block until the limit is no longer exceeded.
800 883
801 The default value is very large, so there is no practical limit on 884 The default value is very large, so there is no practical limit on
802 the number of outstanding requests. 885 the number of outstanding requests.
803 886
804 You can still queue as many requests as you want. Therefore, 887 You can still queue as many requests as you want. Therefore,
805 "max_oustsanding" is mainly useful in simple scripts (with low 888 "max_outstanding" is mainly useful in simple scripts (with low
806 values) or as a stop gap to shield against fatal memory overflow 889 values) or as a stop gap to shield against fatal memory overflow
807 (with large values). 890 (with large values).
808 891
809 STATISTICAL INFORMATION 892 STATISTICAL INFORMATION
810 IO::AIO::nreqs 893 IO::AIO::nreqs
847 bytes of memory. In addition, stat requests need a stat buffer (possibly 930 bytes of memory. In addition, stat requests need a stat buffer (possibly
848 a few hundred bytes), readdir requires a result buffer and so on. Perl 931 a few hundred bytes), readdir requires a result buffer and so on. Perl
849 scalars and other data passed into aio requests will also be locked and 932 scalars and other data passed into aio requests will also be locked and
850 will consume memory till the request has entered the done state. 933 will consume memory till the request has entered the done state.
851 934
852 This is now awfully much, so queuing lots of requests is not usually a 935 This is not awfully much, so queuing lots of requests is not usually a
853 problem. 936 problem.
854 937
855 Per-thread usage: 938 Per-thread usage:
856 939
857 In the execution phase, some aio requests require more memory for 940 In the execution phase, some aio requests require more memory for
860 943
861KNOWN BUGS 944KNOWN BUGS
862 Known bugs will be fixed in the next release. 945 Known bugs will be fixed in the next release.
863 946
864SEE ALSO 947SEE ALSO
865 Coro::AIO. 948 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
949 more natural syntax.
866 950
867AUTHOR 951AUTHOR
868 Marc Lehmann <schmorp@schmorp.de> 952 Marc Lehmann <schmorp@schmorp.de>
869 http://home.schmorp.de/ 953 http://home.schmorp.de/
870 954

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