1 | NAME |
1 | NAME |
2 | AnyEvent - provide framework for multiple event loops |
2 | AnyEvent - provide framework for multiple event loops |
3 | |
3 | |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event |
4 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported |
5 | loops |
5 | event loops. |
6 | |
6 | |
7 | SYNOPSIS |
7 | SYNOPSIS |
8 | use AnyEvent; |
8 | use AnyEvent; |
9 | |
9 | |
10 | # file descriptor readable |
10 | # file descriptor readable |
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169 | |
169 | |
170 | I/O WATCHERS |
170 | I/O WATCHERS |
171 | You can create an I/O watcher by calling the "AnyEvent->io" method with |
171 | You can create an I/O watcher by calling the "AnyEvent->io" method with |
172 | the following mandatory key-value pairs as arguments: |
172 | the following mandatory key-value pairs as arguments: |
173 | |
173 | |
174 | "fh" is the Perl *file handle* (*not* file descriptor) to watch for |
174 | "fh" is the Perl *file handle* (or a naked file descriptor) to watch for |
175 | events (AnyEvent might or might not keep a reference to this file |
175 | events (AnyEvent might or might not keep a reference to this file |
176 | handle). Note that only file handles pointing to things for which |
176 | handle). Note that only file handles pointing to things for which |
177 | non-blocking operation makes sense are allowed. This includes sockets, |
177 | non-blocking operation makes sense are allowed. This includes sockets, |
178 | most character devices, pipes, fifos and so on, but not for example |
178 | most character devices, pipes, fifos and so on, but not for example |
179 | files or block devices. |
179 | files or block devices. |
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380 | |
380 | |
381 | There is a slight catch to child watchers, however: you usually start |
381 | There is a slight catch to child watchers, however: you usually start |
382 | them *after* the child process was created, and this means the process |
382 | them *after* the child process was created, and this means the process |
383 | could have exited already (and no SIGCHLD will be sent anymore). |
383 | could have exited already (and no SIGCHLD will be sent anymore). |
384 | |
384 | |
385 | Not all event models handle this correctly (POE doesn't), but even for |
385 | Not all event models handle this correctly (neither POE nor IO::Async |
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386 | do, see their AnyEvent::Impl manpages for details), but even for event |
386 | event models that *do* handle this correctly, they usually need to be |
387 | models that *do* handle this correctly, they usually need to be loaded |
387 | loaded before the process exits (i.e. before you fork in the first |
388 | before the process exits (i.e. before you fork in the first place). |
388 | place). |
389 | AnyEvent's pure perl event loop handles all cases correctly regardless |
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390 | of when you start the watcher. |
389 | |
391 | |
390 | This means you cannot create a child watcher as the very first thing in |
392 | This means you cannot create a child watcher as the very first thing in |
391 | an AnyEvent program, you *have* to create at least one watcher before |
393 | an AnyEvent program, you *have* to create at least one watcher before |
392 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
394 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
393 | |
395 | |
394 | Example: fork a process and wait for it |
396 | Example: fork a process and wait for it |
395 | |
397 | |
396 | my $done = AnyEvent->condvar; |
398 | my $done = AnyEvent->condvar; |
397 | |
399 | |
398 | my $pid = fork or exit 5; |
400 | my $pid = fork or exit 5; |
399 | |
401 | |
400 | my $w = AnyEvent->child ( |
402 | my $w = AnyEvent->child ( |
401 | pid => $pid, |
403 | pid => $pid, |
402 | cb => sub { |
404 | cb => sub { |
403 | my ($pid, $status) = @_; |
405 | my ($pid, $status) = @_; |
404 | warn "pid $pid exited with status $status"; |
406 | warn "pid $pid exited with status $status"; |
405 | $done->send; |
407 | $done->send; |
406 | }, |
408 | }, |
407 | ); |
409 | ); |
408 | |
410 | |
409 | # do something else, then wait for process exit |
411 | # do something else, then wait for process exit |
410 | $done->recv; |
412 | $done->recv; |
411 | |
413 | |
412 | IDLE WATCHERS |
414 | IDLE WATCHERS |
413 | Sometimes there is a need to do something, but it is not so important to |
415 | Sometimes there is a need to do something, but it is not so important to |
414 | do it instantly, but only when there is nothing better to do. This |
416 | do it instantly, but only when there is nothing better to do. This |
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575 | This can be used to signal any errors to the condition variable |
577 | This can be used to signal any errors to the condition variable |
576 | user/consumer. |
578 | user/consumer. |
577 | |
579 | |
578 | $cv->begin ([group callback]) |
580 | $cv->begin ([group callback]) |
579 | $cv->end |
581 | $cv->end |
580 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
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581 | |
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582 | These two methods can be used to combine many transactions/events |
582 | These two methods can be used to combine many transactions/events |
583 | into one. For example, a function that pings many hosts in parallel |
583 | into one. For example, a function that pings many hosts in parallel |
584 | might want to use a condition variable for the whole process. |
584 | might want to use a condition variable for the whole process. |
585 | |
585 | |
586 | Every call to "->begin" will increment a counter, and every call to |
586 | Every call to "->begin" will increment a counter, and every call to |
587 | "->end" will decrement it. If the counter reaches 0 in "->end", the |
587 | "->end" will decrement it. If the counter reaches 0 in "->end", the |
588 | (last) callback passed to "begin" will be executed. That callback is |
588 | (last) callback passed to "begin" will be executed. That callback is |
589 | *supposed* to call "->send", but that is not required. If no |
589 | *supposed* to call "->send", but that is not required. If no |
590 | callback was set, "send" will be called without any arguments. |
590 | callback was set, "send" will be called without any arguments. |
591 | |
591 | |
592 | Let's clarify this with the ping example: |
592 | You can think of "$cv->send" giving you an OR condition (one call |
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593 | sends), while "$cv->begin" and "$cv->end" giving you an AND |
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594 | condition (all "begin" calls must be "end"'ed before the condvar |
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595 | sends). |
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596 | |
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597 | Let's start with a simple example: you have two I/O watchers (for |
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598 | example, STDOUT and STDERR for a program), and you want to wait for |
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599 | both streams to close before activating a condvar: |
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600 | |
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601 | my $cv = AnyEvent->condvar; |
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602 | |
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603 | $cv->begin; # first watcher |
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604 | my $w1 = AnyEvent->io (fh => $fh1, cb => sub { |
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605 | defined sysread $fh1, my $buf, 4096 |
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606 | or $cv->end; |
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607 | }); |
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608 | |
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609 | $cv->begin; # second watcher |
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610 | my $w2 = AnyEvent->io (fh => $fh2, cb => sub { |
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611 | defined sysread $fh2, my $buf, 4096 |
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612 | or $cv->end; |
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613 | }); |
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614 | |
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615 | $cv->recv; |
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616 | |
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617 | This works because for every event source (EOF on file handle), |
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618 | there is one call to "begin", so the condvar waits for all calls to |
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619 | "end" before sending. |
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620 | |
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621 | The ping example mentioned above is slightly more complicated, as |
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622 | the there are results to be passwd back, and the number of tasks |
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623 | that are begung can potentially be zero: |
593 | |
624 | |
594 | my $cv = AnyEvent->condvar; |
625 | my $cv = AnyEvent->condvar; |
595 | |
626 | |
596 | my %result; |
627 | my %result; |
597 | $cv->begin (sub { $cv->send (\%result) }); |
628 | $cv->begin (sub { $cv->send (\%result) }); |
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617 | the loop, which serves two important purposes: first, it sets the |
648 | the loop, which serves two important purposes: first, it sets the |
618 | callback to be called once the counter reaches 0, and second, it |
649 | callback to be called once the counter reaches 0, and second, it |
619 | ensures that "send" is called even when "no" hosts are being pinged |
650 | ensures that "send" is called even when "no" hosts are being pinged |
620 | (the loop doesn't execute once). |
651 | (the loop doesn't execute once). |
621 | |
652 | |
622 | This is the general pattern when you "fan out" into multiple |
653 | This is the general pattern when you "fan out" into multiple (but |
623 | subrequests: use an outer "begin"/"end" pair to set the callback and |
654 | potentially none) subrequests: use an outer "begin"/"end" pair to |
624 | ensure "end" is called at least once, and then, for each subrequest |
655 | set the callback and ensure "end" is called at least once, and then, |
625 | you start, call "begin" and for each subrequest you finish, call |
656 | for each subrequest you start, call "begin" and for each subrequest |
626 | "end". |
657 | you finish, call "end". |
627 | |
658 | |
628 | METHODS FOR CONSUMERS |
659 | METHODS FOR CONSUMERS |
629 | These methods should only be used by the consuming side, i.e. the code |
660 | These methods should only be used by the consuming side, i.e. the code |
630 | awaits the condition. |
661 | awaits the condition. |
631 | |
662 | |
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678 | The callback will be called when the condition becomes "true", i.e. |
709 | The callback will be called when the condition becomes "true", i.e. |
679 | when "send" or "croak" are called, with the only argument being the |
710 | when "send" or "croak" are called, with the only argument being the |
680 | condition variable itself. Calling "recv" inside the callback or at |
711 | condition variable itself. Calling "recv" inside the callback or at |
681 | any later time is guaranteed not to block. |
712 | any later time is guaranteed not to block. |
682 | |
713 | |
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714 | SUPPORTED EVENT LOOPS/BACKENDS |
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715 | The available backend classes are (every class has its own manpage): |
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716 | |
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717 | Backends that are autoprobed when no other event loop can be found. |
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718 | EV is the preferred backend when no other event loop seems to be in |
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719 | use. If EV is not installed, then AnyEvent will try Event, and, |
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720 | failing that, will fall back to its own pure-perl implementation, |
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721 | which is available everywhere as it comes with AnyEvent itself. |
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722 | |
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723 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
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724 | AnyEvent::Impl::Event based on Event, very stable, few glitches. |
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725 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
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726 | |
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727 | Backends that are transparently being picked up when they are used. |
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728 | These will be used when they are currently loaded when the first |
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729 | watcher is created, in which case it is assumed that the application |
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730 | is using them. This means that AnyEvent will automatically pick the |
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731 | right backend when the main program loads an event module before |
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732 | anything starts to create watchers. Nothing special needs to be done |
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733 | by the main program. |
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734 | |
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735 | AnyEvent::Impl::Glib based on Glib, slow but very stable. |
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736 | AnyEvent::Impl::Tk based on Tk, very broken. |
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737 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
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738 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
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739 | |
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740 | Backends with special needs. |
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741 | Qt requires the Qt::Application to be instantiated first, but will |
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742 | otherwise be picked up automatically. As long as the main program |
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743 | instantiates the application before any AnyEvent watchers are |
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744 | created, everything should just work. |
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745 | |
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746 | AnyEvent::Impl::Qt based on Qt. |
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747 | |
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748 | Support for IO::Async can only be partial, as it is too broken and |
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749 | architecturally limited to even support the AnyEvent API. It also is |
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750 | the only event loop that needs the loop to be set explicitly, so it |
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751 | can only be used by a main program knowing about AnyEvent. See |
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752 | AnyEvent::Impl::Async for the gory details. |
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753 | |
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754 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed. |
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755 | |
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756 | Event loops that are indirectly supported via other backends. |
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757 | Some event loops can be supported via other modules: |
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758 | |
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759 | There is no direct support for WxWidgets (Wx) or Prima. |
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760 | |
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761 | WxWidgets has no support for watching file handles. However, you can |
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762 | use WxWidgets through the POE adaptor, as POE has a Wx backend that |
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763 | simply polls 20 times per second, which was considered to be too |
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764 | horrible to even consider for AnyEvent. |
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765 | |
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766 | Prima is not supported as nobody seems to be using it, but it has a |
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767 | POE backend, so it can be supported through POE. |
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768 | |
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769 | AnyEvent knows about both Prima and Wx, however, and will try to |
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770 | load POE when detecting them, in the hope that POE will pick them |
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771 | up, in which case everything will be automatic. |
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772 | |
683 | GLOBAL VARIABLES AND FUNCTIONS |
773 | GLOBAL VARIABLES AND FUNCTIONS |
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774 | These are not normally required to use AnyEvent, but can be useful to |
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775 | write AnyEvent extension modules. |
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776 | |
684 | $AnyEvent::MODEL |
777 | $AnyEvent::MODEL |
685 | Contains "undef" until the first watcher is being created. Then it |
778 | Contains "undef" until the first watcher is being created, before |
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779 | the backend has been autodetected. |
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780 | |
686 | contains the event model that is being used, which is the name of |
781 | Afterwards it contains the event model that is being used, which is |
687 | the Perl class implementing the model. This class is usually one of |
782 | the name of the Perl class implementing the model. This class is |
688 | the "AnyEvent::Impl:xxx" modules, but can be any other class in the |
783 | usually one of the "AnyEvent::Impl:xxx" modules, but can be any |
689 | case AnyEvent has been extended at runtime (e.g. in *rxvt-unicode*). |
784 | other class in the case AnyEvent has been extended at runtime (e.g. |
690 | |
785 | in *rxvt-unicode* it will be "urxvt::anyevent"). |
691 | The known classes so far are: |
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692 | |
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693 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
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694 | AnyEvent::Impl::Event based on Event, second best choice. |
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695 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
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696 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
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697 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
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698 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
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699 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
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700 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
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701 | |
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702 | There is no support for WxWidgets, as WxWidgets has no support for |
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703 | watching file handles. However, you can use WxWidgets through the |
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704 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
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705 | second, which was considered to be too horrible to even consider for |
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706 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by |
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707 | using it's adaptor. |
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708 | |
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709 | AnyEvent knows about Prima and Wx and will try to use POE when |
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710 | autodetecting them. |
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711 | |
786 | |
712 | AnyEvent::detect |
787 | AnyEvent::detect |
713 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
788 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
714 | if necessary. You should only call this function right before you |
789 | if necessary. You should only call this function right before you |
715 | would have created an AnyEvent watcher anyway, that is, as late as |
790 | would have created an AnyEvent watcher anyway, that is, as late as |
716 | possible at runtime. |
791 | possible at runtime, and not e.g. while initialising of your module. |
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792 | |
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793 | If you need to do some initialisation before AnyEvent watchers are |
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794 | created, use "post_detect". |
717 | |
795 | |
718 | $guard = AnyEvent::post_detect { BLOCK } |
796 | $guard = AnyEvent::post_detect { BLOCK } |
719 | Arranges for the code block to be executed as soon as the event |
797 | Arranges for the code block to be executed as soon as the event |
720 | model is autodetected (or immediately if this has already happened). |
798 | model is autodetected (or immediately if this has already happened). |
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799 | |
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800 | The block will be executed *after* the actual backend has been |
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801 | detected ($AnyEvent::MODEL is set), but *before* any watchers have |
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802 | been created, so it is possible to e.g. patch @AnyEvent::ISA or do |
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803 | other initialisations - see the sources of AnyEvent::Strict or |
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804 | AnyEvent::AIO to see how this is used. |
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805 | |
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806 | The most common usage is to create some global watchers, without |
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807 | forcing event module detection too early, for example, AnyEvent::AIO |
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808 | creates and installs the global IO::AIO watcher in a "post_detect" |
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809 | block to avoid autodetecting the event module at load time. |
721 | |
810 | |
722 | If called in scalar or list context, then it creates and returns an |
811 | If called in scalar or list context, then it creates and returns an |
723 | object that automatically removes the callback again when it is |
812 | object that automatically removes the callback again when it is |
724 | destroyed. See Coro::BDB for a case where this is useful. |
813 | destroyed. See Coro::BDB for a case where this is useful. |
725 | |
814 | |
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727 | If there are any code references in this array (you can "push" to it |
816 | If there are any code references in this array (you can "push" to it |
728 | before or after loading AnyEvent), then they will called directly |
817 | before or after loading AnyEvent), then they will called directly |
729 | after the event loop has been chosen. |
818 | after the event loop has been chosen. |
730 | |
819 | |
731 | You should check $AnyEvent::MODEL before adding to this array, |
820 | You should check $AnyEvent::MODEL before adding to this array, |
732 | though: if it contains a true value then the event loop has already |
821 | though: if it is defined then the event loop has already been |
733 | been detected, and the array will be ignored. |
822 | detected, and the array will be ignored. |
734 | |
823 | |
735 | Best use "AnyEvent::post_detect { BLOCK }" instead. |
824 | Best use "AnyEvent::post_detect { BLOCK }" when your application |
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825 | allows it,as it takes care of these details. |
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826 | |
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827 | This variable is mainly useful for modules that can do something |
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828 | useful when AnyEvent is used and thus want to know when it is |
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829 | initialised, but do not need to even load it by default. This array |
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830 | provides the means to hook into AnyEvent passively, without loading |
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831 | it. |
736 | |
832 | |
737 | WHAT TO DO IN A MODULE |
833 | WHAT TO DO IN A MODULE |
738 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
834 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
739 | freely, but you should not load a specific event module or rely on it. |
835 | freely, but you should not load a specific event module or rely on it. |
740 | |
836 | |
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791 | variable somewhere, waiting for it, and sending it when the program |
887 | variable somewhere, waiting for it, and sending it when the program |
792 | should exit cleanly. |
888 | should exit cleanly. |
793 | |
889 | |
794 | OTHER MODULES |
890 | OTHER MODULES |
795 | The following is a non-exhaustive list of additional modules that use |
891 | The following is a non-exhaustive list of additional modules that use |
796 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
892 | AnyEvent as a client and can therefore be mixed easily with other |
797 | in the same program. Some of the modules come with AnyEvent, some are |
893 | AnyEvent modules and other event loops in the same program. Some of the |
798 | available via CPAN. |
894 | modules come with AnyEvent, most are available via CPAN. |
799 | |
895 | |
800 | AnyEvent::Util |
896 | AnyEvent::Util |
801 | Contains various utility functions that replace often-used but |
897 | Contains various utility functions that replace often-used but |
802 | blocking functions such as "inet_aton" by event-/callback-based |
898 | blocking functions such as "inet_aton" by event-/callback-based |
803 | versions. |
899 | versions. |
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809 | more. |
905 | more. |
810 | |
906 | |
811 | AnyEvent::Handle |
907 | AnyEvent::Handle |
812 | Provide read and write buffers, manages watchers for reads and |
908 | Provide read and write buffers, manages watchers for reads and |
813 | writes, supports raw and formatted I/O, I/O queued and fully |
909 | writes, supports raw and formatted I/O, I/O queued and fully |
814 | transparent and non-blocking SSL/TLS. |
910 | transparent and non-blocking SSL/TLS (via AnyEvent::TLS. |
815 | |
911 | |
816 | AnyEvent::DNS |
912 | AnyEvent::DNS |
817 | Provides rich asynchronous DNS resolver capabilities. |
913 | Provides rich asynchronous DNS resolver capabilities. |
818 | |
914 | |
819 | AnyEvent::HTTP |
915 | AnyEvent::HTTP |
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840 | |
936 | |
841 | AnyEvent::GPSD |
937 | AnyEvent::GPSD |
842 | A non-blocking interface to gpsd, a daemon delivering GPS |
938 | A non-blocking interface to gpsd, a daemon delivering GPS |
843 | information. |
939 | information. |
844 | |
940 | |
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941 | AnyEvent::IRC |
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942 | AnyEvent based IRC client module family (replacing the older |
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943 | Net::IRC3). |
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944 | |
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945 | AnyEvent::XMPP |
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946 | AnyEvent based XMPP (Jabber protocol) module family (replacing the |
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947 | older Net::XMPP2>. |
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948 | |
845 | AnyEvent::IGS |
949 | AnyEvent::IGS |
846 | A non-blocking interface to the Internet Go Server protocol (used by |
950 | A non-blocking interface to the Internet Go Server protocol (used by |
847 | App::IGS). |
951 | App::IGS). |
848 | |
952 | |
849 | AnyEvent::IRC |
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850 | AnyEvent based IRC client module family (replacing the older |
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851 | Net::IRC3). |
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852 | |
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853 | Net::XMPP2 |
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854 | AnyEvent based XMPP (Jabber protocol) module family. |
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855 | |
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856 | Net::FCP |
953 | Net::FCP |
857 | AnyEvent-based implementation of the Freenet Client Protocol, |
954 | AnyEvent-based implementation of the Freenet Client Protocol, |
858 | birthplace of AnyEvent. |
955 | birthplace of AnyEvent. |
859 | |
956 | |
860 | Event::ExecFlow |
957 | Event::ExecFlow |
861 | High level API for event-based execution flow control. |
958 | High level API for event-based execution flow control. |
862 | |
959 | |
863 | Coro |
960 | Coro |
864 | Has special support for AnyEvent via Coro::AnyEvent. |
961 | Has special support for AnyEvent via Coro::AnyEvent. |
865 | |
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|
866 | IO::Lambda |
|
|
867 | The lambda approach to I/O - don't ask, look there. Can use |
|
|
868 | AnyEvent. |
|
|
869 | |
962 | |
870 | ERROR AND EXCEPTION HANDLING |
963 | ERROR AND EXCEPTION HANDLING |
871 | In general, AnyEvent does not do any error handling - it relies on the |
964 | In general, AnyEvent does not do any error handling - it relies on the |
872 | caller to do that if required. The AnyEvent::Strict module (see also the |
965 | caller to do that if required. The AnyEvent::Strict module (see also the |
873 | "PERL_ANYEVENT_STRICT" environment variable, below) provides strict |
966 | "PERL_ANYEVENT_STRICT" environment variable, below) provides strict |
… | |
… | |
883 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
976 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
884 | Glib uses "install_exception_handler" and so on. |
977 | Glib uses "install_exception_handler" and so on. |
885 | |
978 | |
886 | ENVIRONMENT VARIABLES |
979 | ENVIRONMENT VARIABLES |
887 | The following environment variables are used by this module or its |
980 | The following environment variables are used by this module or its |
888 | submodules: |
981 | submodules. |
|
|
982 | |
|
|
983 | Note that AnyEvent will remove *all* environment variables starting with |
|
|
984 | "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is |
|
|
985 | enabled. |
889 | |
986 | |
890 | "PERL_ANYEVENT_VERBOSE" |
987 | "PERL_ANYEVENT_VERBOSE" |
891 | By default, AnyEvent will be completely silent except in fatal |
988 | By default, AnyEvent will be completely silent except in fatal |
892 | conditions. You can set this environment variable to make AnyEvent |
989 | conditions. You can set this environment variable to make AnyEvent |
893 | more talkative. |
990 | more talkative. |
… | |
… | |
902 | "PERL_ANYEVENT_STRICT" |
999 | "PERL_ANYEVENT_STRICT" |
903 | AnyEvent does not do much argument checking by default, as thorough |
1000 | AnyEvent does not do much argument checking by default, as thorough |
904 | argument checking is very costly. Setting this variable to a true |
1001 | argument checking is very costly. Setting this variable to a true |
905 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1002 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
906 | thoroughly check the arguments passed to most method calls. If it |
1003 | thoroughly check the arguments passed to most method calls. If it |
907 | finds any problems it will croak. |
1004 | finds any problems, it will croak. |
908 | |
1005 | |
909 | In other words, enables "strict" mode. |
1006 | In other words, enables "strict" mode. |
910 | |
1007 | |
911 | Unlike "use strict", it is definitely recommended ot keep it off in |
1008 | Unlike "use strict", it is definitely recommended to keep it off in |
912 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
1009 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
913 | while developing programs can be very useful, however. |
1010 | while developing programs can be very useful, however. |
914 | |
1011 | |
915 | "PERL_ANYEVENT_MODEL" |
1012 | "PERL_ANYEVENT_MODEL" |
916 | This can be used to specify the event model to be used by AnyEvent, |
1013 | This can be used to specify the event model to be used by AnyEvent, |
… | |
… | |
959 | EDNS0 in its DNS requests. |
1056 | EDNS0 in its DNS requests. |
960 | |
1057 | |
961 | "PERL_ANYEVENT_MAX_FORKS" |
1058 | "PERL_ANYEVENT_MAX_FORKS" |
962 | The maximum number of child processes that |
1059 | The maximum number of child processes that |
963 | "AnyEvent::Util::fork_call" will create in parallel. |
1060 | "AnyEvent::Util::fork_call" will create in parallel. |
|
|
1061 | |
|
|
1062 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
|
|
1063 | The default value for the "max_outstanding" parameter for the |
|
|
1064 | default DNS resolver - this is the maximum number of parallel DNS |
|
|
1065 | requests that are sent to the DNS server. |
|
|
1066 | |
|
|
1067 | "PERL_ANYEVENT_RESOLV_CONF" |
|
|
1068 | The file to use instead of /etc/resolv.conf (or OS-specific |
|
|
1069 | configuration) in the default resolver. When set to the empty |
|
|
1070 | string, no default config will be used. |
|
|
1071 | |
|
|
1072 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
|
|
1073 | When neither "ca_file" nor "ca_path" was specified during |
|
|
1074 | AnyEvent::TLS context creation, and either of these environment |
|
|
1075 | variables exist, they will be used to specify CA certificate |
|
|
1076 | locations instead of a system-dependent default. |
964 | |
1077 | |
965 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1078 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
966 | This is an advanced topic that you do not normally need to use AnyEvent |
1079 | This is an advanced topic that you do not normally need to use AnyEvent |
967 | in a module. This section is only of use to event loop authors who want |
1080 | in a module. This section is only of use to event loop authors who want |
968 | to provide AnyEvent compatibility. |
1081 | to provide AnyEvent compatibility. |
… | |
… | |
1204 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1317 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1205 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1318 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1206 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1319 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1207 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1320 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1208 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
1321 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
|
|
1322 | IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll |
|
|
1323 | IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll |
1209 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1324 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1210 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1325 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1211 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1326 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1212 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1327 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1213 | |
1328 | |
… | |
… | |
1242 | few of them active), of course, but this was not subject of this |
1357 | few of them active), of course, but this was not subject of this |
1243 | benchmark. |
1358 | benchmark. |
1244 | |
1359 | |
1245 | The "Event" module has a relatively high setup and callback invocation |
1360 | The "Event" module has a relatively high setup and callback invocation |
1246 | cost, but overall scores in on the third place. |
1361 | cost, but overall scores in on the third place. |
|
|
1362 | |
|
|
1363 | "IO::Async" performs admirably well, about on par with "Event", even |
|
|
1364 | when using its pure perl backend. |
1247 | |
1365 | |
1248 | "Glib"'s memory usage is quite a bit higher, but it features a faster |
1366 | "Glib"'s memory usage is quite a bit higher, but it features a faster |
1249 | callback invocation and overall ends up in the same class as "Event". |
1367 | callback invocation and overall ends up in the same class as "Event". |
1250 | However, Glib scales extremely badly, doubling the number of watchers |
1368 | However, Glib scales extremely badly, doubling the number of watchers |
1251 | increases the processing time by more than a factor of four, making it |
1369 | increases the processing time by more than a factor of four, making it |
… | |
… | |
1322 | single "request", that is, reading the token from the pipe and |
1440 | single "request", that is, reading the token from the pipe and |
1323 | forwarding it to another server. This includes deleting the old timeout |
1441 | forwarding it to another server. This includes deleting the old timeout |
1324 | and creating a new one that moves the timeout into the future. |
1442 | and creating a new one that moves the timeout into the future. |
1325 | |
1443 | |
1326 | Results |
1444 | Results |
1327 | name sockets create request |
1445 | name sockets create request |
1328 | EV 20000 69.01 11.16 |
1446 | EV 20000 69.01 11.16 |
1329 | Perl 20000 73.32 35.87 |
1447 | Perl 20000 73.32 35.87 |
|
|
1448 | IOAsync 20000 157.00 98.14 epoll |
|
|
1449 | IOAsync 20000 159.31 616.06 poll |
1330 | Event 20000 212.62 257.32 |
1450 | Event 20000 212.62 257.32 |
1331 | Glib 20000 651.16 1896.30 |
1451 | Glib 20000 651.16 1896.30 |
1332 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1452 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1333 | |
1453 | |
1334 | Discussion |
1454 | Discussion |
1335 | This benchmark *does* measure scalability and overall performance of the |
1455 | This benchmark *does* measure scalability and overall performance of the |
1336 | particular event loop. |
1456 | particular event loop. |
1337 | |
1457 | |
1338 | EV is again fastest. Since it is using epoll on my system, the setup |
1458 | EV is again fastest. Since it is using epoll on my system, the setup |
1339 | time is relatively high, though. |
1459 | time is relatively high, though. |
1340 | |
1460 | |
1341 | Perl surprisingly comes second. It is much faster than the C-based event |
1461 | Perl surprisingly comes second. It is much faster than the C-based event |
1342 | loops Event and Glib. |
1462 | loops Event and Glib. |
|
|
1463 | |
|
|
1464 | IO::Async performs very well when using its epoll backend, and still |
|
|
1465 | quite good compared to Glib when using its pure perl backend. |
1343 | |
1466 | |
1344 | Event suffers from high setup time as well (look at its code and you |
1467 | Event suffers from high setup time as well (look at its code and you |
1345 | will understand why). Callback invocation also has a high overhead |
1468 | will understand why). Callback invocation also has a high overhead |
1346 | compared to the "$_->() for .."-style loop that the Perl event loop |
1469 | compared to the "$_->() for .."-style loop that the Perl event loop |
1347 | uses. Event uses select or poll in basically all documented |
1470 | uses. Event uses select or poll in basically all documented |
… | |
… | |
1398 | |
1521 | |
1399 | Summary |
1522 | Summary |
1400 | * C-based event loops perform very well with small number of watchers, |
1523 | * C-based event loops perform very well with small number of watchers, |
1401 | as the management overhead dominates. |
1524 | as the management overhead dominates. |
1402 | |
1525 | |
|
|
1526 | THE IO::Lambda BENCHMARK |
|
|
1527 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
1528 | could be misinterpreted to make AnyEvent look bad. In fact, the |
|
|
1529 | benchmark simply compares IO::Lambda with POE, and IO::Lambda looks |
|
|
1530 | better (which shouldn't come as a surprise to anybody). As such, the |
|
|
1531 | benchmark is fine, and mostly shows that the AnyEvent backend from |
|
|
1532 | IO::Lambda isn't very optimal. But how would AnyEvent compare when used |
|
|
1533 | without the extra baggage? To explore this, I wrote the equivalent |
|
|
1534 | benchmark for AnyEvent. |
|
|
1535 | |
|
|
1536 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
1537 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
1538 | creates the next connection. This is a rather bad benchmark, as it |
|
|
1539 | doesn't test the efficiency of the framework or much non-blocking I/O, |
|
|
1540 | but it is a benchmark nevertheless. |
|
|
1541 | |
|
|
1542 | name runtime |
|
|
1543 | Lambda/select 0.330 sec |
|
|
1544 | + optimized 0.122 sec |
|
|
1545 | Lambda/AnyEvent 0.327 sec |
|
|
1546 | + optimized 0.138 sec |
|
|
1547 | Raw sockets/select 0.077 sec |
|
|
1548 | POE/select, components 0.662 sec |
|
|
1549 | POE/select, raw sockets 0.226 sec |
|
|
1550 | POE/select, optimized 0.404 sec |
|
|
1551 | |
|
|
1552 | AnyEvent/select/nb 0.085 sec |
|
|
1553 | AnyEvent/EV/nb 0.068 sec |
|
|
1554 | +state machine 0.134 sec |
|
|
1555 | |
|
|
1556 | The benchmark is also a bit unfair (my fault): the IO::Lambda/POE |
|
|
1557 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
1558 | defeating the purpose of an event-based solution. All of the newly |
|
|
1559 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
1560 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
1561 | resolver), so AnyEvent is at a disadvantage here, as non-blocking |
|
|
1562 | connects generally require a lot more bookkeeping and event handling |
|
|
1563 | than blocking connects (which involve a single syscall only). |
|
|
1564 | |
|
|
1565 | The last AnyEvent benchmark additionally uses AnyEvent::Handle, which |
|
|
1566 | offers similar expressive power as POE and IO::Lambda, using |
|
|
1567 | conventional Perl syntax. This means that both the echo server and the |
|
|
1568 | client are 100% non-blocking, further placing it at a disadvantage. |
|
|
1569 | |
|
|
1570 | As you can see, the AnyEvent + EV combination even beats the |
|
|
1571 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
|
|
1572 | backend easily beats IO::Lambda and POE. |
|
|
1573 | |
|
|
1574 | And even the 100% non-blocking version written using the high-level (and |
|
|
1575 | slow :) AnyEvent::Handle abstraction beats both POE and IO::Lambda by a |
|
|
1576 | large margin, even though it does all of DNS, tcp-connect and socket I/O |
|
|
1577 | in a non-blocking way. |
|
|
1578 | |
|
|
1579 | The two AnyEvent benchmarks programs can be found as eg/ae0.pl and |
|
|
1580 | eg/ae2.pl in the AnyEvent distribution, the remaining benchmarks are |
|
|
1581 | part of the IO::lambda distribution and were used without any changes. |
|
|
1582 | |
1403 | SIGNALS |
1583 | SIGNALS |
1404 | AnyEvent currently installs handlers for these signals: |
1584 | AnyEvent currently installs handlers for these signals: |
1405 | |
1585 | |
1406 | SIGCHLD |
1586 | SIGCHLD |
1407 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
1587 | A handler for "SIGCHLD" is installed by AnyEvent's child watcher |
1408 | emulation for event loops that do not support them natively. Also, |
1588 | emulation for event loops that do not support them natively. Also, |
1409 | some event loops install a similar handler. |
1589 | some event loops install a similar handler. |
|
|
1590 | |
|
|
1591 | Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, |
|
|
1592 | then AnyEvent will reset it to default, to avoid losing child exit |
|
|
1593 | statuses. |
1410 | |
1594 | |
1411 | SIGPIPE |
1595 | SIGPIPE |
1412 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
1596 | A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is |
1413 | "undef" when AnyEvent gets loaded. |
1597 | "undef" when AnyEvent gets loaded. |
1414 | |
1598 | |
… | |
… | |
1442 | |
1626 | |
1443 | You can make AnyEvent completely ignore this variable by deleting it |
1627 | You can make AnyEvent completely ignore this variable by deleting it |
1444 | before the first watcher gets created, e.g. with a "BEGIN" block: |
1628 | before the first watcher gets created, e.g. with a "BEGIN" block: |
1445 | |
1629 | |
1446 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1630 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1447 | |
1631 | |
1448 | use AnyEvent; |
1632 | use AnyEvent; |
1449 | |
1633 | |
1450 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1634 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1451 | be used to probe what backend is used and gain other information (which |
1635 | be used to probe what backend is used and gain other information (which |
1452 | is probably even less useful to an attacker than PERL_ANYEVENT_MODEL), |
1636 | is probably even less useful to an attacker than PERL_ANYEVENT_MODEL), |
1453 | and $ENV{PERL_ANYEGENT_STRICT}. |
1637 | and $ENV{PERL_ANYEVENT_STRICT}. |
|
|
1638 | |
|
|
1639 | Note that AnyEvent will remove *all* environment variables starting with |
|
|
1640 | "PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is |
|
|
1641 | enabled. |
1454 | |
1642 | |
1455 | BUGS |
1643 | BUGS |
1456 | Perl 5.8 has numerous memleaks that sometimes hit this module and are |
1644 | Perl 5.8 has numerous memleaks that sometimes hit this module and are |
1457 | hard to work around. If you suffer from memleaks, first upgrade to Perl |
1645 | hard to work around. If you suffer from memleaks, first upgrade to Perl |
1458 | 5.10 and check wether the leaks still show up. (Perl 5.10.0 has other |
1646 | 5.10 and check wether the leaks still show up. (Perl 5.10.0 has other |
… | |
… | |
1465 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
1653 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
1466 | Event::Lib, Qt, POE. |
1654 | Event::Lib, Qt, POE. |
1467 | |
1655 | |
1468 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1656 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1469 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1657 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1470 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE. |
1658 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
|
|
1659 | AnyEvent::Impl::IOAsync. |
1471 | |
1660 | |
1472 | Non-blocking file handles, sockets, TCP clients and servers: |
1661 | Non-blocking file handles, sockets, TCP clients and servers: |
1473 | AnyEvent::Handle, AnyEvent::Socket. |
1662 | AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS. |
1474 | |
1663 | |
1475 | Asynchronous DNS: AnyEvent::DNS. |
1664 | Asynchronous DNS: AnyEvent::DNS. |
1476 | |
1665 | |
1477 | Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, |
1666 | Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event, |
1478 | |
1667 | |
1479 | Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS. |
1668 | Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::XMPP, |
|
|
1669 | AnyEvent::HTTP. |
1480 | |
1670 | |
1481 | AUTHOR |
1671 | AUTHOR |
1482 | Marc Lehmann <schmorp@schmorp.de> |
1672 | Marc Lehmann <schmorp@schmorp.de> |
1483 | http://home.schmorp.de/ |
1673 | http://home.schmorp.de/ |
1484 | |
1674 | |