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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.71 by root, Fri Apr 25 07:29:42 2008 UTC vs.
Revision 1.75 by root, Fri Apr 25 07:49:39 2008 UTC

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899I<destroy> is the time, in microseconds, that it takes to destroy a single 899I<destroy> is the time, in microseconds, that it takes to destroy a single
900watcher. 900watcher.
901 901
902=head2 Results 902=head2 Results
903 903
904 name watcher bytes create invoke destroy comment 904 name watchers bytes create invoke destroy comment
905 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 905 EV/EV 400000 244 0.56 0.46 0.31 EV native interface
906 EV/Any 100000 610 3.52 0.91 0.75 EV + AnyEvent watchers 906 EV/Any 100000 610 3.52 0.91 0.75 EV + AnyEvent watchers
907 CoroEV/Any 100000 610 3.49 0.92 0.75 coroutines + Coro::Signal 907 CoroEV/Any 100000 610 3.49 0.92 0.75 coroutines + Coro::Signal
908 Perl/Any 16000 654 4.64 1.22 0.77 pure perl implementation 908 Perl/Any 16000 654 4.64 1.22 0.77 pure perl implementation
909 Event/Event 16000 523 28.05 21.38 0.86 Event native interface 909 Event/Event 16000 523 28.05 21.38 0.86 Event native interface
910 Event/Any 16000 943 34.43 20.48 1.39 Event + AnyEvent watchers 910 Event/Any 16000 943 34.43 20.48 1.39 Event + AnyEvent watchers
911 Glib/Any 16000 1357 96.99 12.55 55.51 quadratic behaviour 911 Glib/Any 16000 1357 96.99 12.55 55.51 quadratic behaviour
912 Tk/Any 2000 1855 27.01 66.61 14.03 SEGV with >> 2000 watchers 912 Tk/Any 2000 1855 27.01 66.61 14.03 SEGV with >> 2000 watchers
913 POE/Event 2000 6644 108.15 768.19 14.33 via POE::Loop::Event 913 POE/Event 2000 6644 108.15 768.19 14.33 via POE::Loop::Event
914 POE/Select 2000 6343 94.69 807.65 562.69 via POE::Loop::Select 914 POE/Select 2000 6343 94.69 807.65 562.69 via POE::Loop::Select
915 915
916=head2 Discussion 916=head2 Discussion
917 917
918The benchmark does I<not> measure scalability of the event loop very 918The benchmark does I<not> measure scalability of the event loop very
919well. For example, a select-based event loop (such as the pure perl one) 919well. For example, a select-based event loop (such as the pure perl one)
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935but this was not subjetc of this benchmark. 935but this was not subjetc of this benchmark.
936 936
937The C<Event> module has a relatively high setup and callback invocation cost, 937The C<Event> module has a relatively high setup and callback invocation cost,
938but overall scores on the third place. 938but overall scores on the third place.
939 939
940C<Glib>'s memory usage is quite a bit bit higher, features a faster 940C<Glib>'s memory usage is quite a bit bit higher, but it features a
941callback invocation and overall lands in the same class as C<Event>. 941faster callback invocation and overall ends up in the same class as
942C<Event>. However, Glib scales extremely badly, doubling the number of
943watchers increases the processing time by more than a factor of four,
944making it completely unusable when using larger numbers of watchers
945(note that only a single file descriptor was used in the benchmark, so
946inefficiencies of C<poll> do not account for this).
942 947
943The C<Tk> adaptor works relatively well, the fact that it crashes with 948The C<Tk> adaptor works relatively well. The fact that it crashes with
944more than 2000 watchers is a big setback, however, as correctness takes 949more than 2000 watchers is a big setback, however, as correctness takes
945precedence over speed. Nevertheless, its performance is surprising, as the 950precedence over speed. Nevertheless, its performance is surprising, as the
946file descriptor is dup()ed for each watcher. This shows that the dup() 951file descriptor is dup()ed for each watcher. This shows that the dup()
947employed by some adaptors is not a big performance issue (it does incur a 952employed by some adaptors is not a big performance issue (it does incur a
948hidden memory cost inside the kernel, though). 953hidden memory cost inside the kernel, though, that is not reflected in the
954figures above).
949 955
950C<POE>, regardless of backend (wether using its pure perl select-based 956C<POE>, regardless of underlying event loop (wether using its pure perl
951backend or the Event backend) shows abysmal performance and memory 957select-based backend or the Event module) shows abysmal performance and
952usage: Watchers use almost 30 times as much memory as EV watchers, and 10 958memory usage: Watchers use almost 30 times as much memory as EV watchers,
953times as much memory as both Event or EV via AnyEvent. Watcher invocation 959and 10 times as much memory as both Event or EV via AnyEvent. Watcher
954is almost 700 times slower as with AnyEvent's pure perl implementation. 960invocation is almost 700 times slower than with AnyEvent's pure perl
961implementation. The design of the POE adaptor class in AnyEvent can not
962really account for this, as session creation overhead is small compared
963to execution of the state machine, which is coded pretty optimally within
964L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.
955 965
966=head2 Summary
967
956Summary: using EV through AnyEvent is faster than any other event 968Using EV through AnyEvent is faster than any other event loop, but most
957loop. The overhead AnyEvent adds can be very small, and you should avoid 969event loops have acceptable performance with or without AnyEvent.
958POE like the plague if you want performance or reasonable memory usage. 970
971The overhead AnyEvent adds is usually much smaller than the overhead of
972the actual event loop, only with extremely fast event loops such as the EV
973adds AnyEvent significant overhead.
974
975And you should simply avoid POE like the plague if you want performance or
976reasonable memory usage.
959 977
960 978
961=head1 FORK 979=head1 FORK
962 980
963Most event libraries are not fork-safe. The ones who are usually are 981Most event libraries are not fork-safe. The ones who are usually are

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