… | |
… | |
79 | our $VERSION = '2.0'; |
79 | our $VERSION = '2.0'; |
80 | |
80 | |
81 | our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
81 | our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat |
82 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
82 | aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink |
83 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
83 | aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move |
84 | aio_group); |
84 | aio_group aio_nop); |
85 | our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
85 | our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); |
86 | |
86 | |
87 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
87 | @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; |
88 | |
88 | |
89 | require XSLoader; |
89 | require XSLoader; |
… | |
… | |
352 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
352 | Scans a directory (similar to C<aio_readdir>) but additionally tries to |
353 | separate the entries of directory C<$path> into two sets of names, ones |
353 | separate the entries of directory C<$path> into two sets of names, ones |
354 | you can recurse into (directories or links to them), and ones you cannot |
354 | you can recurse into (directories or links to them), and ones you cannot |
355 | recurse into (everything else). |
355 | recurse into (everything else). |
356 | |
356 | |
357 | C<aio_scandir> is a composite request that consists of many sub |
357 | C<aio_scandir> is a composite request that creates of many sub requests_ |
358 | requests. C<$maxreq> specifies the maximum number of outstanding aio |
358 | C<$maxreq> specifies the maximum number of outstanding aio requests that |
359 | requests that this function generates. If it is C<< <= 0 >>, then a |
359 | this function generates. If it is C<< <= 0 >>, then a suitable default |
360 | suitable default will be chosen (currently 8). |
360 | will be chosen (currently 6). |
361 | |
361 | |
362 | On error, the callback is called without arguments, otherwise it receives |
362 | On error, the callback is called without arguments, otherwise it receives |
363 | two array-refs with path-relative entry names. |
363 | two array-refs with path-relative entry names. |
364 | |
364 | |
365 | Example: |
365 | Example: |
… | |
… | |
404 | sub aio_scandir($$$) { |
404 | sub aio_scandir($$$) { |
405 | my ($path, $maxreq, $cb) = @_; |
405 | my ($path, $maxreq, $cb) = @_; |
406 | |
406 | |
407 | my $grp = aio_group $cb; |
407 | my $grp = aio_group $cb; |
408 | |
408 | |
409 | $maxreq = 8 if $maxreq <= 0; |
409 | $maxreq = 6 if $maxreq <= 0; |
410 | |
410 | |
411 | # stat once |
411 | # stat once |
412 | add $grp aio_stat $path, sub { |
412 | add $grp aio_stat $path, sub { |
413 | return $grp->result () if $_[0]; |
413 | return $grp->result () if $_[0]; |
414 | my $now = time; |
414 | my $now = time; |
… | |
… | |
445 | my (@dirs, @nondirs); |
445 | my (@dirs, @nondirs); |
446 | |
446 | |
447 | my ($statcb, $schedcb); |
447 | my ($statcb, $schedcb); |
448 | my $nreq = 0; |
448 | my $nreq = 0; |
449 | |
449 | |
|
|
450 | my $statgrp = add $grp aio_group; |
|
|
451 | |
450 | $schedcb = sub { |
452 | $schedcb = sub { |
451 | if (@$entries) { |
453 | if (@$entries) { |
452 | if ($nreq < $maxreq) { |
454 | if ($nreq < $maxreq) { |
453 | my $ent = pop @$entries; |
455 | my $ent = pop @$entries; |
454 | $nreq++; |
456 | $nreq++; |
455 | add $grp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
457 | add $statgrp aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) }; |
456 | } |
458 | } |
457 | } elsif (!$nreq) { |
459 | } elsif (!$nreq) { |
458 | # finished |
460 | # finished |
|
|
461 | $statgrp->cancel; |
459 | undef $statcb; |
462 | undef $statcb; |
460 | undef $schedcb; |
463 | undef $schedcb; |
461 | $grp->result (\@dirs, \@nondirs) if $cb; |
464 | $grp->result (\@dirs, \@nondirs); |
462 | undef $cb; |
|
|
463 | } |
465 | } |
464 | }; |
466 | }; |
465 | $statcb = sub { |
467 | $statcb = sub { |
466 | my ($status, $entry) = @_; |
468 | my ($status, $entry) = @_; |
467 | |
469 | |
… | |
… | |
531 | add $grp |
533 | add $grp |
532 | (aio_stat ...), |
534 | (aio_stat ...), |
533 | (aio_stat ...), |
535 | (aio_stat ...), |
534 | ...; |
536 | ...; |
535 | |
537 | |
|
|
538 | =item aio_nop $callback->() |
|
|
539 | |
|
|
540 | This is a special request - it does nothing in itself and is only used for |
|
|
541 | side effects, such as when you want to add a dummy request to a group so |
|
|
542 | that finishing the requests in the group depends on executing the given |
|
|
543 | code. |
|
|
544 | |
|
|
545 | While this request does nothing, it still goes through the execution |
|
|
546 | phase and still requires a worker thread. Thus, the callback will not |
|
|
547 | be executed immediately but only after other requests in the queue have |
|
|
548 | entered their execution phase. This can be used to measure request |
|
|
549 | latency. |
|
|
550 | |
536 | =item IO::AIO::aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
551 | =item IO::AIO::aio_sleep $fractional_seconds, $callback->() *NOT EXPORTED* |
537 | |
552 | |
538 | Mainly used for debugging and benchmarking, this aio request puts one of |
553 | Mainly used for debugging and benchmarking, this aio request puts one of |
539 | the request workers to sleep for the given time. |
554 | the request workers to sleep for the given time. |
540 | |
555 | |
… | |
… | |
558 | callback) and B<done> (request has reached the end of its lifetime and |
573 | callback) and B<done> (request has reached the end of its lifetime and |
559 | holds no resources anymore). |
574 | holds no resources anymore). |
560 | |
575 | |
561 | =over 4 |
576 | =over 4 |
562 | |
577 | |
563 | =item $req->cancel |
578 | =item cancel $req |
564 | |
579 | |
565 | Cancels the request, if possible. Has the effect of skipping execution |
580 | Cancels the request, if possible. Has the effect of skipping execution |
566 | when entering the B<execute> state and skipping calling the callback when |
581 | when entering the B<execute> state and skipping calling the callback when |
567 | entering the the B<result> state, but will leave the request otherwise |
582 | entering the the B<result> state, but will leave the request otherwise |
568 | untouched. That means that requests that currently execute will not be |
583 | untouched. That means that requests that currently execute will not be |
569 | stopped and resources held by the request will not be freed prematurely. |
584 | stopped and resources held by the request will not be freed prematurely. |
570 | |
585 | |
|
|
586 | =item cb $req $callback->(...) |
|
|
587 | |
|
|
588 | Replace (or simply set) the callback registered to the request. |
|
|
589 | |
571 | =back |
590 | =back |
572 | |
591 | |
573 | =head2 IO::AIO::GRP CLASS |
592 | =head2 IO::AIO::GRP CLASS |
574 | |
593 | |
575 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
594 | This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to |
… | |
… | |
601 | }; |
620 | }; |
602 | |
621 | |
603 | This makes it very easy to create composite requests (see the source of |
622 | This makes it very easy to create composite requests (see the source of |
604 | C<aio_move> for an application) that work and feel like simple requests. |
623 | C<aio_move> for an application) that work and feel like simple requests. |
605 | |
624 | |
|
|
625 | =over 4 |
|
|
626 | |
606 | The IO::AIO::GRP objects will be cleaned up during calls to |
627 | =item * The IO::AIO::GRP objects will be cleaned up during calls to |
607 | C<IO::AIO::poll_cb>, just like any other request. |
628 | C<IO::AIO::poll_cb>, just like any other request. |
608 | |
629 | |
609 | They can be canceled like any other request. Canceling will cancel not |
630 | =item * They can be canceled like any other request. Canceling will cancel not |
610 | just the request itself, but also all requests it contains. |
631 | only the request itself, but also all requests it contains. |
611 | |
632 | |
612 | They can also can also be added to other IO::AIO::GRP objects. |
633 | =item * They can also can also be added to other IO::AIO::GRP objects. |
|
|
634 | |
|
|
635 | =item * You must not add requests to a group from within the group callback (or |
|
|
636 | any later time). |
|
|
637 | |
|
|
638 | =item * This does not harmonise well with C<max_outstanding>, so best do |
|
|
639 | not combine C<aio_group> with it. Groups and feeders are recommended for |
|
|
640 | this kind of concurrency-limiting. |
|
|
641 | |
|
|
642 | =back |
613 | |
643 | |
614 | Their lifetime, simplified, looks like this: when they are empty, they |
644 | Their lifetime, simplified, looks like this: when they are empty, they |
615 | will finish very quickly. If they contain only requests that are in the |
645 | will finish very quickly. If they contain only requests that are in the |
616 | C<done> state, they will also finish. Otherwise they will continue to |
646 | C<done> state, they will also finish. Otherwise they will continue to |
617 | exist. |
647 | exist. |
… | |
… | |
621 | group. And only when all those requests have finished will the the group |
651 | group. And only when all those requests have finished will the the group |
622 | itself finish. |
652 | itself finish. |
623 | |
653 | |
624 | =over 4 |
654 | =over 4 |
625 | |
655 | |
|
|
656 | =item add $grp ... |
|
|
657 | |
626 | =item $grp->add (...) |
658 | =item $grp->add (...) |
627 | |
|
|
628 | =item add $grp ... |
|
|
629 | |
659 | |
630 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
660 | Add one or more requests to the group. Any type of L<IO::AIO::REQ> can |
631 | be added, including other groups, as long as you do not create circular |
661 | be added, including other groups, as long as you do not create circular |
632 | dependencies. |
662 | dependencies. |
633 | |
663 | |
… | |
… | |
635 | |
665 | |
636 | =item $grp->result (...) |
666 | =item $grp->result (...) |
637 | |
667 | |
638 | Set the result value(s) that will be passed to the group callback when all |
668 | Set the result value(s) that will be passed to the group callback when all |
639 | subrequests have finished. By default, no argument will be passed. |
669 | subrequests have finished. By default, no argument will be passed. |
|
|
670 | |
|
|
671 | =item feed $grp $callback->($grp) |
|
|
672 | |
|
|
673 | [VERY EXPERIMENTAL] |
|
|
674 | |
|
|
675 | Sets a feeder/generator on this group: every group can have an attached |
|
|
676 | generator that generates requests if idle. The idea behind this is that, |
|
|
677 | although you could just queue as many requests as you want in a group, |
|
|
678 | this might starve other requests for a potentially long time. For |
|
|
679 | example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> |
|
|
680 | requests, delaying any later requests for a long time. |
|
|
681 | |
|
|
682 | To avoid this, and allow incremental generation of requests, you can |
|
|
683 | instead a group and set a feeder on it that generates those requests. The |
|
|
684 | feed callback will be called whenever there are few enough (see C<feed_limit>, |
|
|
685 | below) requests active in the group itself and is expected to queue more |
|
|
686 | requests. |
|
|
687 | |
|
|
688 | The feed can queue as many requests as it likes (i.e. C<add> does not |
|
|
689 | impose any limits). |
|
|
690 | |
|
|
691 | If the feed does not queue more requests when called, it will be |
|
|
692 | automatically removed from the group. |
|
|
693 | |
|
|
694 | If the feed limit is C<0>, it will be set to C<2> automatically. |
|
|
695 | |
|
|
696 | Example: |
|
|
697 | |
|
|
698 | # stat all files in @files, but only ever use four aio requests concurrently: |
|
|
699 | |
|
|
700 | my $grp = aio_group sub { print "finished\n" }; |
|
|
701 | feed_limit $grp 4; |
|
|
702 | feed $grp sub { |
|
|
703 | my $file = pop @files |
|
|
704 | or return; |
|
|
705 | |
|
|
706 | add $grp aio_stat $file, sub { ... }; |
|
|
707 | }; |
|
|
708 | |
|
|
709 | =item feed_limit $grp $num |
|
|
710 | |
|
|
711 | Sets the feeder limit for the group: The feeder will be called whenever |
|
|
712 | the group contains less than this many requests. |
|
|
713 | |
|
|
714 | Setting the limit to C<0> will pause the feeding process. |
640 | |
715 | |
641 | =back |
716 | =back |
642 | |
717 | |
643 | =head2 SUPPORT FUNCTIONS |
718 | =head2 SUPPORT FUNCTIONS |
644 | |
719 | |
… | |
… | |
702 | IO::AIO::poll_wait, IO::AIO::poll_cb |
777 | IO::AIO::poll_wait, IO::AIO::poll_cb |
703 | if IO::AIO::nreqs; |
778 | if IO::AIO::nreqs; |
704 | |
779 | |
705 | =item IO::AIO::min_parallel $nthreads |
780 | =item IO::AIO::min_parallel $nthreads |
706 | |
781 | |
707 | Set the minimum number of AIO threads to C<$nthreads>. The current default |
782 | Set the minimum number of AIO threads to C<$nthreads>. The current |
708 | is C<4>, which means four asynchronous operations can be done at one time |
783 | default is C<8>, which means eight asynchronous operations can execute |
709 | (the number of outstanding operations, however, is unlimited). |
784 | concurrently at any one time (the number of outstanding requests, |
|
|
785 | however, is unlimited). |
710 | |
786 | |
711 | IO::AIO starts threads only on demand, when an AIO request is queued and |
787 | IO::AIO starts threads only on demand, when an AIO request is queued and |
712 | no free thread exists. |
788 | no free thread exists. |
713 | |
789 | |
714 | It is recommended to keep the number of threads low, as some Linux |
790 | It is recommended to keep the number of threads relatively low, as some |
715 | kernel versions will scale negatively with the number of threads (higher |
791 | Linux kernel versions will scale negatively with the number of threads |
716 | parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32 |
792 | (higher parallelity => MUCH higher latency). With current Linux 2.6 |
717 | threads should be fine. |
793 | versions, 4-32 threads should be fine. |
718 | |
794 | |
719 | Under most circumstances you don't need to call this function, as the |
795 | Under most circumstances you don't need to call this function, as the |
720 | module selects a default that is suitable for low to moderate load. |
796 | module selects a default that is suitable for low to moderate load. |
721 | |
797 | |
722 | =item IO::AIO::max_parallel $nthreads |
798 | =item IO::AIO::max_parallel $nthreads |
… | |
… | |
733 | |
809 | |
734 | Under normal circumstances you don't need to call this function. |
810 | Under normal circumstances you don't need to call this function. |
735 | |
811 | |
736 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
812 | =item $oldnreqs = IO::AIO::max_outstanding $nreqs |
737 | |
813 | |
|
|
814 | [DEPRECATED] |
|
|
815 | |
738 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
816 | Sets the maximum number of outstanding requests to C<$nreqs>. If you |
739 | try to queue up more than this number of requests, the caller will block until |
817 | try to queue up more than this number of requests, the caller will block until |
740 | some requests have been handled. |
818 | some requests have been handled. |
741 | |
819 | |
742 | The default is very large, so normally there is no practical limit. If you |
820 | The default is very large, so normally there is no practical limit. If you |
743 | queue up many requests in a loop it often improves speed if you set |
821 | queue up many requests in a loop it often improves speed if you set |
744 | this to a relatively low number, such as C<100>. |
822 | this to a relatively low number, such as C<100>. |
|
|
823 | |
|
|
824 | This function does not work well together with C<aio_group>'s, and their |
|
|
825 | feeder interface is better suited to limiting concurrency, so do not use |
|
|
826 | this function. |
745 | |
827 | |
746 | Under normal circumstances you don't need to call this function. |
828 | Under normal circumstances you don't need to call this function. |
747 | |
829 | |
748 | =back |
830 | =back |
749 | |
831 | |
… | |
… | |
763 | or return undef; |
845 | or return undef; |
764 | |
846 | |
765 | *$sym |
847 | *$sym |
766 | } |
848 | } |
767 | |
849 | |
768 | min_parallel 4; |
850 | min_parallel 8; |
769 | |
851 | |
770 | END { |
852 | END { |
771 | max_parallel 0; |
853 | max_parallel 0; |
772 | } |
854 | } |
773 | |
855 | |
… | |
… | |
787 | |
869 | |
788 | In short: the parent will, after a short pause, continue as if fork had |
870 | In short: the parent will, after a short pause, continue as if fork had |
789 | not been called, while the child will act as if IO::AIO has not been used |
871 | not been called, while the child will act as if IO::AIO has not been used |
790 | yet. |
872 | yet. |
791 | |
873 | |
|
|
874 | =head2 MEMORY USAGE |
|
|
875 | |
|
|
876 | Each aio request uses - depending on your architecture - around 128 bytes |
|
|
877 | of memory. In addition, stat requests need a stat buffer (possibly a few |
|
|
878 | hundred bytes). Perl scalars and other data passed into aio requests will |
|
|
879 | also be locked. |
|
|
880 | |
|
|
881 | This is now awfully much, so queuing lots of requests is not usually a |
|
|
882 | problem. |
|
|
883 | |
|
|
884 | Each thread needs a stack area which is usually around 16k, sometimes much |
|
|
885 | larger, depending on the OS. |
|
|
886 | |
792 | =head1 SEE ALSO |
887 | =head1 SEE ALSO |
793 | |
888 | |
794 | L<Coro>, L<Linux::AIO> (obsolete). |
889 | L<Coro>, L<Linux::AIO> (obsolete). |
795 | |
890 | |
796 | =head1 AUTHOR |
891 | =head1 AUTHOR |