… | |
… | |
80 | module. |
80 | module. |
81 | |
81 | |
82 | During the first call of any watcher-creation method, the module tries |
82 | During the first call of any watcher-creation method, the module tries |
83 | to detect the currently loaded event loop by probing whether one of the |
83 | to detect the currently loaded event loop by probing whether one of the |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
85 | L<Event>, L<Glib>, L<Tk>, L<AnyEvent::Impl::Perl>, L<Event::Lib>, L<Qt>, |
85 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
86 | L<POE>. The first one found is used. If none are found, the module tries |
86 | L<POE>. The first one found is used. If none are found, the module tries |
87 | to load these modules (excluding Event::Lib, Qt and POE as the pure perl |
87 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
88 | adaptor should always succeed) in the order given. The first one that can |
88 | adaptor should always succeed) in the order given. The first one that can |
89 | be successfully loaded will be used. If, after this, still none could be |
89 | be successfully loaded will be used. If, after this, still none could be |
90 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
90 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
91 | very efficient, but should work everywhere. |
91 | very efficient, but should work everywhere. |
92 | |
92 | |
… | |
… | |
136 | |
136 | |
137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
137 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
138 | my variables are only visible after the statement in which they are |
138 | my variables are only visible after the statement in which they are |
139 | declared. |
139 | declared. |
140 | |
140 | |
141 | =head2 IO WATCHERS |
141 | =head2 I/O WATCHERS |
142 | |
142 | |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
143 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
144 | with the following mandatory key-value pairs as arguments: |
144 | with the following mandatory key-value pairs as arguments: |
145 | |
145 | |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
146 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
… | |
… | |
359 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
359 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
360 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
360 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
361 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
361 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
362 | AnyEvent::Impl::Event based on Event, second best choice. |
362 | AnyEvent::Impl::Event based on Event, second best choice. |
363 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
363 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
|
|
364 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
364 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
365 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
365 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
366 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
366 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
367 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
367 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
368 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
368 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
369 | |
369 | |
370 | There is no support for WxWidgets, as WxWidgets has no support for |
370 | There is no support for WxWidgets, as WxWidgets has no support for |
… | |
… | |
706 | |
706 | |
707 | =back |
707 | =back |
708 | |
708 | |
709 | =head1 EXAMPLE PROGRAM |
709 | =head1 EXAMPLE PROGRAM |
710 | |
710 | |
711 | The following program uses an IO watcher to read data from STDIN, a timer |
711 | The following program uses an I/O watcher to read data from STDIN, a timer |
712 | to display a message once per second, and a condition variable to quit the |
712 | to display a message once per second, and a condition variable to quit the |
713 | program when the user enters quit: |
713 | program when the user enters quit: |
714 | |
714 | |
715 | use AnyEvent; |
715 | use AnyEvent; |
716 | |
716 | |
… | |
… | |
867 | |
867 | |
868 | To give you an idea of the performance and overheads that AnyEvent adds |
868 | To give you an idea of the performance and overheads that AnyEvent adds |
869 | over the event loops themselves (and to give you an impression of the |
869 | over the event loops themselves (and to give you an impression of the |
870 | speed of various event loops), here is a benchmark of various supported |
870 | speed of various event loops), here is a benchmark of various supported |
871 | event models natively and with anyevent. The benchmark creates a lot of |
871 | event models natively and with anyevent. The benchmark creates a lot of |
872 | timers (with a zero timeout) and io watchers (watching STDOUT, a pty, to |
872 | timers (with a zero timeout) and I/O watchers (watching STDOUT, a pty, to |
873 | become writable, which it is), lets them fire exactly once and destroys |
873 | become writable, which it is), lets them fire exactly once and destroys |
874 | them again. |
874 | them again. |
875 | |
875 | |
876 | Rewriting the benchmark to use many different sockets instead of using |
876 | Rewriting the benchmark to use many different sockets instead of using |
877 | the same filehandle for all io watchers results in a much longer runtime |
877 | the same filehandle for all I/O watchers results in a much longer runtime |
878 | (socket creation is expensive), but qualitatively the same figures, so it |
878 | (socket creation is expensive), but qualitatively the same figures, so it |
879 | was not used. |
879 | was not used. |
880 | |
880 | |
881 | =head2 Explanation of the columns |
881 | =head2 Explanation of the columns |
882 | |
882 | |
… | |
… | |
921 | =head2 Discussion |
921 | =head2 Discussion |
922 | |
922 | |
923 | The benchmark does I<not> measure scalability of the event loop very |
923 | The benchmark does I<not> measure scalability of the event loop very |
924 | well. For example, a select-based event loop (such as the pure perl one) |
924 | well. For example, a select-based event loop (such as the pure perl one) |
925 | can never compete with an event loop that uses epoll when the number of |
925 | can never compete with an event loop that uses epoll when the number of |
926 | file descriptors grows high. In this benchmark, only a single filehandle |
926 | file descriptors grows high. In this benchmark, all events become ready at |
927 | is used (although some of the AnyEvent adaptors dup() its file descriptor |
927 | the same time, so select/poll-based implementations get an unnatural speed |
928 | to worka round bugs). |
928 | boost. |
929 | |
929 | |
930 | C<EV> is the sole leader regarding speed and memory use, which are both |
930 | C<EV> is the sole leader regarding speed and memory use, which are both |
931 | maximal/minimal, respectively. Even when going through AnyEvent, there are |
931 | maximal/minimal, respectively. Even when going through AnyEvent, there are |
932 | only two event loops that use slightly less memory (the C<Event> module |
932 | only two event loops that use slightly less memory (the C<Event> module |
933 | natively and the pure perl backend), and no faster event models, not even |
933 | natively and the pure perl backend), and no faster event models, not even |
… | |
… | |
962 | |
962 | |
963 | C<POE>, regardless of underlying event loop (wether using its pure perl |
963 | C<POE>, regardless of underlying event loop (wether using its pure perl |
964 | select-based backend or the Event module) shows abysmal performance and |
964 | select-based backend or the Event module) shows abysmal performance and |
965 | memory usage: Watchers use almost 30 times as much memory as EV watchers, |
965 | memory usage: Watchers use almost 30 times as much memory as EV watchers, |
966 | and 10 times as much memory as both Event or EV via AnyEvent. Watcher |
966 | and 10 times as much memory as both Event or EV via AnyEvent. Watcher |
967 | invocation is almost 700 times slower than with AnyEvent's pure perl |
967 | invocation is almost 900 times slower than with AnyEvent's pure perl |
968 | implementation. The design of the POE adaptor class in AnyEvent can not |
968 | implementation. The design of the POE adaptor class in AnyEvent can not |
969 | really account for this, as session creation overhead is small compared |
969 | really account for this, as session creation overhead is small compared |
970 | to execution of the state machine, which is coded pretty optimally within |
970 | to execution of the state machine, which is coded pretty optimally within |
971 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
971 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
972 | |
972 | |