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Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC vs.
Revision 1.230 by root, Wed Jul 8 05:55:17 2009 UTC

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176=head2 I/O WATCHERS 176=head2 I/O WATCHERS
177 177
178You can create an I/O watcher by calling the C<< AnyEvent->io >> method 178You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
180 180
181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch 181C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182for events (AnyEvent might or might not keep a reference to this file 182for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which 183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets, 184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files 185most character devices, pipes, fifos and so on, but not for example files
186or block devices. 186or block devices.
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599 599
600=item $cv->begin ([group callback]) 600=item $cv->begin ([group callback])
601 601
602=item $cv->end 602=item $cv->end
603 603
604These two methods are EXPERIMENTAL and MIGHT CHANGE.
605
606These two methods can be used to combine many transactions/events into 604These two methods can be used to combine many transactions/events into
607one. For example, a function that pings many hosts in parallel might want 605one. For example, a function that pings many hosts in parallel might want
608to use a condition variable for the whole process. 606to use a condition variable for the whole process.
609 607
610Every call to C<< ->begin >> will increment a counter, and every call to 608Every call to C<< ->begin >> will increment a counter, and every call to
611C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end 609C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
612>>, the (last) callback passed to C<begin> will be executed. That callback 610>>, the (last) callback passed to C<begin> will be executed. That callback
613is I<supposed> to call C<< ->send >>, but that is not required. If no 611is I<supposed> to call C<< ->send >>, but that is not required. If no
614callback was set, C<send> will be called without any arguments. 612callback was set, C<send> will be called without any arguments.
615 613
616Let's clarify this with the ping example: 614You can think of C<< $cv->send >> giving you an OR condition (one call
615sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617
618Let's start with a simple example: you have two I/O watchers (for example,
619STDOUT and STDERR for a program), and you want to wait for both streams to
620close before activating a condvar:
621
622 my $cv = AnyEvent->condvar;
623
624 $cv->begin; # first watcher
625 my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
626 defined sysread $fh1, my $buf, 4096
627 or $cv->end;
628 });
629
630 $cv->begin; # second watcher
631 my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
632 defined sysread $fh2, my $buf, 4096
633 or $cv->end;
634 });
635
636 $cv->recv;
637
638This works because for every event source (EOF on file handle), there is
639one call to C<begin>, so the condvar waits for all calls to C<end> before
640sending.
641
642The ping example mentioned above is slightly more complicated, as the
643there are results to be passwd back, and the number of tasks that are
644begung can potentially be zero:
617 645
618 my $cv = AnyEvent->condvar; 646 my $cv = AnyEvent->condvar;
619 647
620 my %result; 648 my %result;
621 $cv->begin (sub { $cv->send (\%result) }); 649 $cv->begin (sub { $cv->send (\%result) });
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641loop, which serves two important purposes: first, it sets the callback 669loop, which serves two important purposes: first, it sets the callback
642to be called once the counter reaches C<0>, and second, it ensures that 670to be called once the counter reaches C<0>, and second, it ensures that
643C<send> is called even when C<no> hosts are being pinged (the loop 671C<send> is called even when C<no> hosts are being pinged (the loop
644doesn't execute once). 672doesn't execute once).
645 673
646This is the general pattern when you "fan out" into multiple subrequests: 674This is the general pattern when you "fan out" into multiple (but
647use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 675potentially none) subrequests: use an outer C<begin>/C<end> pair to set
648is called at least once, and then, for each subrequest you start, call 676the callback and ensure C<end> is called at least once, and then, for each
649C<begin> and for each subrequest you finish, call C<end>. 677subrequest you start, call C<begin> and for each subrequest you finish,
678call C<end>.
650 679
651=back 680=back
652 681
653=head3 METHODS FOR CONSUMERS 682=head3 METHODS FOR CONSUMERS
654 683
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839 868
840 869
841=head1 OTHER MODULES 870=head1 OTHER MODULES
842 871
843The following is a non-exhaustive list of additional modules that use 872The following is a non-exhaustive list of additional modules that use
844AnyEvent and can therefore be mixed easily with other AnyEvent modules 873AnyEvent as a client and can therefore be mixed easily with other AnyEvent
845in the same program. Some of the modules come with AnyEvent, some are 874modules and other event loops in the same program. Some of the modules
846available via CPAN. 875come with AnyEvent, most are available via CPAN.
847 876
848=over 4 877=over 4
849 878
850=item L<AnyEvent::Util> 879=item L<AnyEvent::Util>
851 880
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860 889
861=item L<AnyEvent::Handle> 890=item L<AnyEvent::Handle>
862 891
863Provide read and write buffers, manages watchers for reads and writes, 892Provide read and write buffers, manages watchers for reads and writes,
864supports raw and formatted I/O, I/O queued and fully transparent and 893supports raw and formatted I/O, I/O queued and fully transparent and
865non-blocking SSL/TLS. 894non-blocking SSL/TLS (via L<AnyEvent::TLS>.
866 895
867=item L<AnyEvent::DNS> 896=item L<AnyEvent::DNS>
868 897
869Provides rich asynchronous DNS resolver capabilities. 898Provides rich asynchronous DNS resolver capabilities.
870 899
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898 927
899=item L<AnyEvent::GPSD> 928=item L<AnyEvent::GPSD>
900 929
901A non-blocking interface to gpsd, a daemon delivering GPS information. 930A non-blocking interface to gpsd, a daemon delivering GPS information.
902 931
932=item L<AnyEvent::IRC>
933
934AnyEvent based IRC client module family (replacing the older Net::IRC3).
935
936=item L<AnyEvent::XMPP>
937
938AnyEvent based XMPP (Jabber protocol) module family (replacing the older
939Net::XMPP2>.
940
903=item L<AnyEvent::IGS> 941=item L<AnyEvent::IGS>
904 942
905A non-blocking interface to the Internet Go Server protocol (used by 943A non-blocking interface to the Internet Go Server protocol (used by
906L<App::IGS>). 944L<App::IGS>).
907 945
908=item L<AnyEvent::IRC>
909
910AnyEvent based IRC client module family (replacing the older Net::IRC3).
911
912=item L<Net::XMPP2>
913
914AnyEvent based XMPP (Jabber protocol) module family.
915
916=item L<Net::FCP> 946=item L<Net::FCP>
917 947
918AnyEvent-based implementation of the Freenet Client Protocol, birthplace 948AnyEvent-based implementation of the Freenet Client Protocol, birthplace
919of AnyEvent. 949of AnyEvent.
920 950
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924 954
925=item L<Coro> 955=item L<Coro>
926 956
927Has special support for AnyEvent via L<Coro::AnyEvent>. 957Has special support for AnyEvent via L<Coro::AnyEvent>.
928 958
929=item L<IO::Lambda>
930
931The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
932
933=back 959=back
934 960
935=cut 961=cut
936 962
937package AnyEvent; 963package AnyEvent;
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939no warnings; 965no warnings;
940use strict qw(vars subs); 966use strict qw(vars subs);
941 967
942use Carp; 968use Carp;
943 969
944our $VERSION = 4.412; 970our $VERSION = 4.8;
945our $MODEL; 971our $MODEL;
946 972
947our $AUTOLOAD; 973our $AUTOLOAD;
948our @ISA; 974our @ISA;
949 975
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1094# allow only one watcher per fd, so we dup it to get a different one). 1120# allow only one watcher per fd, so we dup it to get a different one).
1095sub _dupfh($$;$$) { 1121sub _dupfh($$;$$) {
1096 my ($poll, $fh, $r, $w) = @_; 1122 my ($poll, $fh, $r, $w) = @_;
1097 1123
1098 # cygwin requires the fh mode to be matching, unix doesn't 1124 # cygwin requires the fh mode to be matching, unix doesn't
1099 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1125 my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
1100 : $poll eq "w" ? ($w, ">")
1101 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1102 1126
1103 open my $fh2, "$mode&" . fileno $fh 1127 open my $fh2, "$mode&", $fh
1104 or die "cannot dup() filehandle: $!,"; 1128 or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1105 1129
1106 # we assume CLOEXEC is already set by perl in all important cases 1130 # we assume CLOEXEC is already set by perl in all important cases
1107 1131
1108 ($fh2, $rw) 1132 ($fh2, $rw)
1109} 1133}
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1441 1465
1442=item C<PERL_ANYEVENT_MAX_FORKS> 1466=item C<PERL_ANYEVENT_MAX_FORKS>
1443 1467
1444The maximum number of child processes that C<AnyEvent::Util::fork_call> 1468The maximum number of child processes that C<AnyEvent::Util::fork_call>
1445will create in parallel. 1469will create in parallel.
1470
1471=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
1472
1473The default value for the C<max_outstanding> parameter for the default DNS
1474resolver - this is the maximum number of parallel DNS requests that are
1475sent to the DNS server.
1476
1477=item C<PERL_ANYEVENT_RESOLV_CONF>
1478
1479The file to use instead of F</etc/resolv.conf> (or OS-specific
1480configuration) in the default resolver. When set to the empty string, no
1481default config will be used.
1482
1483=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1484
1485When neither C<ca_file> nor C<ca_path> was specified during
1486L<AnyEvent::TLS> context creation, and either of these environment
1487variables exist, they will be used to specify CA certificate locations
1488instead of a system-dependent default.
1446 1489
1447=back 1490=back
1448 1491
1449=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1492=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1450 1493
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1695 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1738 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1696 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 1739 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1697 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 1740 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1698 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 1741 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1699 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 1742 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1743 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1744 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1700 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 1745 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1701 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 1746 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1702 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 1747 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1703 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 1748 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1704 1749
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1733performance becomes really bad with lots of file descriptors (and few of 1778performance becomes really bad with lots of file descriptors (and few of
1734them active), of course, but this was not subject of this benchmark. 1779them active), of course, but this was not subject of this benchmark.
1735 1780
1736The C<Event> module has a relatively high setup and callback invocation 1781The C<Event> module has a relatively high setup and callback invocation
1737cost, but overall scores in on the third place. 1782cost, but overall scores in on the third place.
1783
1784C<IO::Async> performs admirably well, about on par with C<Event>, even
1785when using its pure perl backend.
1738 1786
1739C<Glib>'s memory usage is quite a bit higher, but it features a 1787C<Glib>'s memory usage is quite a bit higher, but it features a
1740faster callback invocation and overall ends up in the same class as 1788faster callback invocation and overall ends up in the same class as
1741C<Event>. However, Glib scales extremely badly, doubling the number of 1789C<Event>. However, Glib scales extremely badly, doubling the number of
1742watchers increases the processing time by more than a factor of four, 1790watchers increases the processing time by more than a factor of four,
… …
1820it to another server. This includes deleting the old timeout and creating 1868it to another server. This includes deleting the old timeout and creating
1821a new one that moves the timeout into the future. 1869a new one that moves the timeout into the future.
1822 1870
1823=head3 Results 1871=head3 Results
1824 1872
1825 name sockets create request 1873 name sockets create request
1826 EV 20000 69.01 11.16 1874 EV 20000 69.01 11.16
1827 Perl 20000 73.32 35.87 1875 Perl 20000 73.32 35.87
1876 IOAsync 20000 157.00 98.14 epoll
1877 IOAsync 20000 159.31 616.06 poll
1828 Event 20000 212.62 257.32 1878 Event 20000 212.62 257.32
1829 Glib 20000 651.16 1896.30 1879 Glib 20000 651.16 1896.30
1830 POE 20000 349.67 12317.24 uses POE::Loop::Event 1880 POE 20000 349.67 12317.24 uses POE::Loop::Event
1831 1881
1832=head3 Discussion 1882=head3 Discussion
1833 1883
1834This benchmark I<does> measure scalability and overall performance of the 1884This benchmark I<does> measure scalability and overall performance of the
1835particular event loop. 1885particular event loop.
… …
1837EV is again fastest. Since it is using epoll on my system, the setup time 1887EV is again fastest. Since it is using epoll on my system, the setup time
1838is relatively high, though. 1888is relatively high, though.
1839 1889
1840Perl surprisingly comes second. It is much faster than the C-based event 1890Perl surprisingly comes second. It is much faster than the C-based event
1841loops Event and Glib. 1891loops Event and Glib.
1892
1893IO::Async performs very well when using its epoll backend, and still quite
1894good compared to Glib when using its pure perl backend.
1842 1895
1843Event suffers from high setup time as well (look at its code and you will 1896Event suffers from high setup time as well (look at its code and you will
1844understand why). Callback invocation also has a high overhead compared to 1897understand why). Callback invocation also has a high overhead compared to
1845the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 1898the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1846uses select or poll in basically all documented configurations. 1899uses select or poll in basically all documented configurations.
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2063L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 2116L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2064 2117
2065Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 2118Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2066L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 2119L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2067L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 2120L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2068L<AnyEvent::Impl::POE>. 2121L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
2069 2122
2070Non-blocking file handles, sockets, TCP clients and 2123Non-blocking file handles, sockets, TCP clients and
2071servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. 2124servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2072 2125
2073Asynchronous DNS: L<AnyEvent::DNS>. 2126Asynchronous DNS: L<AnyEvent::DNS>.
2074 2127
2075Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 2128Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
2129L<Coro::Event>,
2076 2130
2077Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. 2131Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
2132L<AnyEvent::HTTP>.
2078 2133
2079 2134
2080=head1 AUTHOR 2135=head1 AUTHOR
2081 2136
2082 Marc Lehmann <schmorp@schmorp.de> 2137 Marc Lehmann <schmorp@schmorp.de>

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