… | |
… | |
176 | =head2 I/O WATCHERS |
176 | =head2 I/O WATCHERS |
177 | |
177 | |
178 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
178 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
179 | with the following mandatory key-value pairs as arguments: |
179 | with the following mandatory key-value pairs as arguments: |
180 | |
180 | |
181 | C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch |
181 | C<fh> is the Perl I<file handle> (I<not> file descriptor, see below) to |
182 | for events (AnyEvent might or might not keep a reference to this file |
182 | watch for events (AnyEvent might or might not keep a reference to this |
183 | handle). Note that only file handles pointing to things for which |
183 | file handle). Note that only file handles pointing to things for which |
184 | non-blocking operation makes sense are allowed. This includes sockets, |
184 | non-blocking operation makes sense are allowed. This includes sockets, |
185 | most character devices, pipes, fifos and so on, but not for example files |
185 | most character devices, pipes, fifos and so on, but not for example files |
186 | or block devices. |
186 | or block devices. |
187 | |
187 | |
188 | C<poll> must be a string that is either C<r> or C<w>, which creates a |
188 | C<poll> must be a string that is either C<r> or C<w>, which creates a |
… | |
… | |
209 | chomp (my $input = <STDIN>); |
209 | chomp (my $input = <STDIN>); |
210 | warn "read: $input\n"; |
210 | warn "read: $input\n"; |
211 | undef $w; |
211 | undef $w; |
212 | }); |
212 | }); |
213 | |
213 | |
|
|
214 | =head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR |
|
|
215 | |
|
|
216 | It is not uncommon to only have a file descriptor, while AnyEvent requires |
|
|
217 | a Perl file handle. |
|
|
218 | |
|
|
219 | There are basically two methods to convert a file descriptor into a file handle. If you own |
|
|
220 | the file descriptor, you can open it with C<&=>, as in: |
|
|
221 | |
|
|
222 | open my $fh, "<&=$fileno" or die "xxx: ยง!"; |
|
|
223 | |
|
|
224 | This will "own" the file descriptor, meaning that when C<$fh> is |
|
|
225 | destroyed, it will automatically close the C<$fileno>. Also, note that |
|
|
226 | the open mode (read, write, read/write) must correspond with how the |
|
|
227 | underlying file descriptor was opened. |
|
|
228 | |
|
|
229 | In many cases, taking over the file descriptor is now what you want, in |
|
|
230 | which case the only alternative is to dup the file descriptor: |
|
|
231 | |
|
|
232 | open my $fh, "<&$fileno" or die "xxx: $!"; |
|
|
233 | |
|
|
234 | This has the advantage of not closing the file descriptor and the |
|
|
235 | disadvantage of making a slow copy. |
|
|
236 | |
214 | =head2 TIME WATCHERS |
237 | =head2 TIME WATCHERS |
215 | |
238 | |
216 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
239 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
217 | method with the following mandatory arguments: |
240 | method with the following mandatory arguments: |
218 | |
241 | |
… | |
… | |
392 | |
415 | |
393 | There is a slight catch to child watchers, however: you usually start them |
416 | There is a slight catch to child watchers, however: you usually start them |
394 | I<after> the child process was created, and this means the process could |
417 | I<after> the child process was created, and this means the process could |
395 | have exited already (and no SIGCHLD will be sent anymore). |
418 | have exited already (and no SIGCHLD will be sent anymore). |
396 | |
419 | |
397 | Not all event models handle this correctly (POE doesn't), but even for |
420 | Not all event models handle this correctly (neither POE nor IO::Async do, |
|
|
421 | see their AnyEvent::Impl manpages for details), but even for event models |
398 | event models that I<do> handle this correctly, they usually need to be |
422 | that I<do> handle this correctly, they usually need to be loaded before |
399 | loaded before the process exits (i.e. before you fork in the first place). |
423 | the process exits (i.e. before you fork in the first place). AnyEvent's |
|
|
424 | pure perl event loop handles all cases correctly regardless of when you |
|
|
425 | start the watcher. |
400 | |
426 | |
401 | This means you cannot create a child watcher as the very first thing in an |
427 | This means you cannot create a child watcher as the very first |
402 | AnyEvent program, you I<have> to create at least one watcher before you |
428 | thing in an AnyEvent program, you I<have> to create at least one |
403 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
429 | watcher before you C<fork> the child (alternatively, you can call |
|
|
430 | C<AnyEvent::detect>). |
404 | |
431 | |
405 | Example: fork a process and wait for it |
432 | Example: fork a process and wait for it |
406 | |
433 | |
407 | my $done = AnyEvent->condvar; |
434 | my $done = AnyEvent->condvar; |
408 | |
435 | |
… | |
… | |
595 | |
622 | |
596 | =item $cv->begin ([group callback]) |
623 | =item $cv->begin ([group callback]) |
597 | |
624 | |
598 | =item $cv->end |
625 | =item $cv->end |
599 | |
626 | |
600 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
|
|
601 | |
|
|
602 | These two methods can be used to combine many transactions/events into |
627 | These two methods can be used to combine many transactions/events into |
603 | one. For example, a function that pings many hosts in parallel might want |
628 | one. For example, a function that pings many hosts in parallel might want |
604 | to use a condition variable for the whole process. |
629 | to use a condition variable for the whole process. |
605 | |
630 | |
606 | Every call to C<< ->begin >> will increment a counter, and every call to |
631 | Every call to C<< ->begin >> will increment a counter, and every call to |
607 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
632 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
608 | >>, the (last) callback passed to C<begin> will be executed. That callback |
633 | >>, the (last) callback passed to C<begin> will be executed. That callback |
609 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
634 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
610 | callback was set, C<send> will be called without any arguments. |
635 | callback was set, C<send> will be called without any arguments. |
611 | |
636 | |
612 | Let's clarify this with the ping example: |
637 | You can think of C<< $cv->send >> giving you an OR condition (one call |
|
|
638 | sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND |
|
|
639 | condition (all C<begin> calls must be C<end>'ed before the condvar sends). |
|
|
640 | |
|
|
641 | Let's start with a simple example: you have two I/O watchers (for example, |
|
|
642 | STDOUT and STDERR for a program), and you want to wait for both streams to |
|
|
643 | close before activating a condvar: |
|
|
644 | |
|
|
645 | my $cv = AnyEvent->condvar; |
|
|
646 | |
|
|
647 | $cv->begin; # first watcher |
|
|
648 | my $w1 = AnyEvent->io (fh => $fh1, cb => sub { |
|
|
649 | defined sysread $fh1, my $buf, 4096 |
|
|
650 | or $cv->end; |
|
|
651 | }); |
|
|
652 | |
|
|
653 | $cv->begin; # second watcher |
|
|
654 | my $w2 = AnyEvent->io (fh => $fh2, cb => sub { |
|
|
655 | defined sysread $fh2, my $buf, 4096 |
|
|
656 | or $cv->end; |
|
|
657 | }); |
|
|
658 | |
|
|
659 | $cv->recv; |
|
|
660 | |
|
|
661 | This works because for every event source (EOF on file handle), there is |
|
|
662 | one call to C<begin>, so the condvar waits for all calls to C<end> before |
|
|
663 | sending. |
|
|
664 | |
|
|
665 | The ping example mentioned above is slightly more complicated, as the |
|
|
666 | there are results to be passwd back, and the number of tasks that are |
|
|
667 | begung can potentially be zero: |
613 | |
668 | |
614 | my $cv = AnyEvent->condvar; |
669 | my $cv = AnyEvent->condvar; |
615 | |
670 | |
616 | my %result; |
671 | my %result; |
617 | $cv->begin (sub { $cv->send (\%result) }); |
672 | $cv->begin (sub { $cv->send (\%result) }); |
… | |
… | |
637 | loop, which serves two important purposes: first, it sets the callback |
692 | loop, which serves two important purposes: first, it sets the callback |
638 | to be called once the counter reaches C<0>, and second, it ensures that |
693 | to be called once the counter reaches C<0>, and second, it ensures that |
639 | C<send> is called even when C<no> hosts are being pinged (the loop |
694 | C<send> is called even when C<no> hosts are being pinged (the loop |
640 | doesn't execute once). |
695 | doesn't execute once). |
641 | |
696 | |
642 | This is the general pattern when you "fan out" into multiple subrequests: |
697 | This is the general pattern when you "fan out" into multiple (but |
643 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
698 | potentially none) subrequests: use an outer C<begin>/C<end> pair to set |
644 | is called at least once, and then, for each subrequest you start, call |
699 | the callback and ensure C<end> is called at least once, and then, for each |
645 | C<begin> and for each subrequest you finish, call C<end>. |
700 | subrequest you start, call C<begin> and for each subrequest you finish, |
|
|
701 | call C<end>. |
646 | |
702 | |
647 | =back |
703 | =back |
648 | |
704 | |
649 | =head3 METHODS FOR CONSUMERS |
705 | =head3 METHODS FOR CONSUMERS |
650 | |
706 | |
… | |
… | |
730 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
786 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
731 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
787 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
732 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
788 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
733 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
789 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
734 | |
790 | |
|
|
791 | # warning, support for IO::Async is only partial, as it is too broken |
|
|
792 | # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async. |
|
|
793 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs). |
|
|
794 | |
735 | There is no support for WxWidgets, as WxWidgets has no support for |
795 | There is no support for WxWidgets, as WxWidgets has no support for |
736 | watching file handles. However, you can use WxWidgets through the |
796 | watching file handles. However, you can use WxWidgets through the |
737 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
797 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
738 | second, which was considered to be too horrible to even consider for |
798 | second, which was considered to be too horrible to even consider for |
739 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
799 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
… | |
… | |
931 | no warnings; |
991 | no warnings; |
932 | use strict qw(vars subs); |
992 | use strict qw(vars subs); |
933 | |
993 | |
934 | use Carp; |
994 | use Carp; |
935 | |
995 | |
936 | our $VERSION = 4.41; |
996 | our $VERSION = 4.8; |
937 | our $MODEL; |
997 | our $MODEL; |
938 | |
998 | |
939 | our $AUTOLOAD; |
999 | our $AUTOLOAD; |
940 | our @ISA; |
1000 | our @ISA; |
941 | |
1001 | |
942 | our @REGISTRY; |
1002 | our @REGISTRY; |
943 | |
1003 | |
944 | our $WIN32; |
1004 | our $WIN32; |
945 | |
1005 | |
946 | BEGIN { |
1006 | BEGIN { |
947 | my $win32 = ! ! ($^O =~ /mswin32/i); |
1007 | eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; |
948 | eval "sub WIN32(){ $win32 }"; |
1008 | eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; |
|
|
1009 | |
|
|
1010 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
|
|
1011 | if ${^TAINT}; |
949 | } |
1012 | } |
950 | |
1013 | |
951 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
1014 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
952 | |
1015 | |
953 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
1016 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
… | |
… | |
971 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
1034 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
972 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
1035 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
973 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
1036 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
974 | [Wx:: => AnyEvent::Impl::POE::], |
1037 | [Wx:: => AnyEvent::Impl::POE::], |
975 | [Prima:: => AnyEvent::Impl::POE::], |
1038 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
1039 | # IO::Async is just too broken - we would need workaorunds for its |
|
|
1040 | # byzantine signal and broken child handling, among others. |
|
|
1041 | # IO::Async is rather hard to detect, as it doesn't have any |
|
|
1042 | # obvious default class. |
|
|
1043 | # [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
1044 | # [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
1045 | # [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program |
976 | ); |
1046 | ); |
977 | |
1047 | |
978 | our %method = map +($_ => 1), |
1048 | our %method = map +($_ => 1), |
979 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
1049 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
980 | |
1050 | |
… | |
… | |
1072 | } |
1142 | } |
1073 | |
1143 | |
1074 | # utility function to dup a filehandle. this is used by many backends |
1144 | # utility function to dup a filehandle. this is used by many backends |
1075 | # to support binding more than one watcher per filehandle (they usually |
1145 | # to support binding more than one watcher per filehandle (they usually |
1076 | # allow only one watcher per fd, so we dup it to get a different one). |
1146 | # allow only one watcher per fd, so we dup it to get a different one). |
1077 | sub _dupfh($$$$) { |
1147 | sub _dupfh($$;$$) { |
1078 | my ($poll, $fh, $r, $w) = @_; |
1148 | my ($poll, $fh, $r, $w) = @_; |
1079 | |
1149 | |
1080 | # cygwin requires the fh mode to be matching, unix doesn't |
1150 | # cygwin requires the fh mode to be matching, unix doesn't |
1081 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
1151 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
1082 | : $poll eq "w" ? ($w, ">") |
1152 | : $poll eq "w" ? ($w, ">") |
… | |
… | |
1337 | so on. |
1407 | so on. |
1338 | |
1408 | |
1339 | =head1 ENVIRONMENT VARIABLES |
1409 | =head1 ENVIRONMENT VARIABLES |
1340 | |
1410 | |
1341 | The following environment variables are used by this module or its |
1411 | The following environment variables are used by this module or its |
1342 | submodules: |
1412 | submodules. |
|
|
1413 | |
|
|
1414 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
1415 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
1416 | enabled. |
1343 | |
1417 | |
1344 | =over 4 |
1418 | =over 4 |
1345 | |
1419 | |
1346 | =item C<PERL_ANYEVENT_VERBOSE> |
1420 | =item C<PERL_ANYEVENT_VERBOSE> |
1347 | |
1421 | |
… | |
… | |
1359 | =item C<PERL_ANYEVENT_STRICT> |
1433 | =item C<PERL_ANYEVENT_STRICT> |
1360 | |
1434 | |
1361 | AnyEvent does not do much argument checking by default, as thorough |
1435 | AnyEvent does not do much argument checking by default, as thorough |
1362 | argument checking is very costly. Setting this variable to a true value |
1436 | argument checking is very costly. Setting this variable to a true value |
1363 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
1437 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
1364 | check the arguments passed to most method calls. If it finds any problems |
1438 | check the arguments passed to most method calls. If it finds any problems, |
1365 | it will croak. |
1439 | it will croak. |
1366 | |
1440 | |
1367 | In other words, enables "strict" mode. |
1441 | In other words, enables "strict" mode. |
1368 | |
1442 | |
1369 | Unlike C<use strict>, it is definitely recommended ot keep it off in |
1443 | Unlike C<use strict>, it is definitely recommended to keep it off in |
1370 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
1444 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
1371 | developing programs can be very useful, however. |
1445 | developing programs can be very useful, however. |
1372 | |
1446 | |
1373 | =item C<PERL_ANYEVENT_MODEL> |
1447 | =item C<PERL_ANYEVENT_MODEL> |
1374 | |
1448 | |
… | |
… | |
1419 | |
1493 | |
1420 | =item C<PERL_ANYEVENT_MAX_FORKS> |
1494 | =item C<PERL_ANYEVENT_MAX_FORKS> |
1421 | |
1495 | |
1422 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
1496 | The maximum number of child processes that C<AnyEvent::Util::fork_call> |
1423 | will create in parallel. |
1497 | will create in parallel. |
|
|
1498 | |
|
|
1499 | =item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS> |
|
|
1500 | |
|
|
1501 | The default value for the C<max_outstanding> parameter for the default DNS |
|
|
1502 | resolver - this is the maximum number of parallel DNS requests that are |
|
|
1503 | sent to the DNS server. |
|
|
1504 | |
|
|
1505 | =item C<PERL_ANYEVENT_RESOLV_CONF> |
|
|
1506 | |
|
|
1507 | The file to use instead of F</etc/resolv.conf> (or OS-specific |
|
|
1508 | configuration) in the default resolver. When set to the empty string, no |
|
|
1509 | default config will be used. |
|
|
1510 | |
|
|
1511 | =item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>. |
|
|
1512 | |
|
|
1513 | When neither C<ca_file> nor C<ca_path> was specified during |
|
|
1514 | L<AnyEvent::TLS> context creation, and either of these environment |
|
|
1515 | variables exist, they will be used to specify CA certificate locations |
|
|
1516 | instead of a system-dependent default. |
1424 | |
1517 | |
1425 | =back |
1518 | =back |
1426 | |
1519 | |
1427 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1520 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1428 | |
1521 | |
… | |
… | |
1673 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1766 | EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers |
1674 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1767 | CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal |
1675 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1768 | Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation |
1676 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1769 | Event/Event 16000 517 32.20 31.80 0.81 Event native interface |
1677 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
1770 | Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers |
|
|
1771 | IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll |
|
|
1772 | IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll |
1678 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1773 | Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour |
1679 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1774 | Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers |
1680 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1775 | POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event |
1681 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1776 | POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select |
1682 | |
1777 | |
… | |
… | |
1711 | performance becomes really bad with lots of file descriptors (and few of |
1806 | performance becomes really bad with lots of file descriptors (and few of |
1712 | them active), of course, but this was not subject of this benchmark. |
1807 | them active), of course, but this was not subject of this benchmark. |
1713 | |
1808 | |
1714 | The C<Event> module has a relatively high setup and callback invocation |
1809 | The C<Event> module has a relatively high setup and callback invocation |
1715 | cost, but overall scores in on the third place. |
1810 | cost, but overall scores in on the third place. |
|
|
1811 | |
|
|
1812 | C<IO::Async> performs admirably well, about on par with C<Event>, even |
|
|
1813 | when using its pure perl backend. |
1716 | |
1814 | |
1717 | C<Glib>'s memory usage is quite a bit higher, but it features a |
1815 | C<Glib>'s memory usage is quite a bit higher, but it features a |
1718 | faster callback invocation and overall ends up in the same class as |
1816 | faster callback invocation and overall ends up in the same class as |
1719 | C<Event>. However, Glib scales extremely badly, doubling the number of |
1817 | C<Event>. However, Glib scales extremely badly, doubling the number of |
1720 | watchers increases the processing time by more than a factor of four, |
1818 | watchers increases the processing time by more than a factor of four, |
… | |
… | |
1798 | it to another server. This includes deleting the old timeout and creating |
1896 | it to another server. This includes deleting the old timeout and creating |
1799 | a new one that moves the timeout into the future. |
1897 | a new one that moves the timeout into the future. |
1800 | |
1898 | |
1801 | =head3 Results |
1899 | =head3 Results |
1802 | |
1900 | |
1803 | name sockets create request |
1901 | name sockets create request |
1804 | EV 20000 69.01 11.16 |
1902 | EV 20000 69.01 11.16 |
1805 | Perl 20000 73.32 35.87 |
1903 | Perl 20000 73.32 35.87 |
|
|
1904 | IOAsync 20000 157.00 98.14 epoll |
|
|
1905 | IOAsync 20000 159.31 616.06 poll |
1806 | Event 20000 212.62 257.32 |
1906 | Event 20000 212.62 257.32 |
1807 | Glib 20000 651.16 1896.30 |
1907 | Glib 20000 651.16 1896.30 |
1808 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1908 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1809 | |
1909 | |
1810 | =head3 Discussion |
1910 | =head3 Discussion |
1811 | |
1911 | |
1812 | This benchmark I<does> measure scalability and overall performance of the |
1912 | This benchmark I<does> measure scalability and overall performance of the |
1813 | particular event loop. |
1913 | particular event loop. |
… | |
… | |
1815 | EV is again fastest. Since it is using epoll on my system, the setup time |
1915 | EV is again fastest. Since it is using epoll on my system, the setup time |
1816 | is relatively high, though. |
1916 | is relatively high, though. |
1817 | |
1917 | |
1818 | Perl surprisingly comes second. It is much faster than the C-based event |
1918 | Perl surprisingly comes second. It is much faster than the C-based event |
1819 | loops Event and Glib. |
1919 | loops Event and Glib. |
|
|
1920 | |
|
|
1921 | IO::Async performs very well when using its epoll backend, and still quite |
|
|
1922 | good compared to Glib when using its pure perl backend. |
1820 | |
1923 | |
1821 | Event suffers from high setup time as well (look at its code and you will |
1924 | Event suffers from high setup time as well (look at its code and you will |
1822 | understand why). Callback invocation also has a high overhead compared to |
1925 | understand why). Callback invocation also has a high overhead compared to |
1823 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
1926 | the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event |
1824 | uses select or poll in basically all documented configurations. |
1927 | uses select or poll in basically all documented configurations. |
… | |
… | |
1887 | =item * C-based event loops perform very well with small number of |
1990 | =item * C-based event loops perform very well with small number of |
1888 | watchers, as the management overhead dominates. |
1991 | watchers, as the management overhead dominates. |
1889 | |
1992 | |
1890 | =back |
1993 | =back |
1891 | |
1994 | |
|
|
1995 | =head2 THE IO::Lambda BENCHMARK |
|
|
1996 | |
|
|
1997 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
1998 | could be misinterpreted to make AnyEvent look bad. In fact, the benchmark |
|
|
1999 | simply compares IO::Lambda with POE, and IO::Lambda looks better (which |
|
|
2000 | shouldn't come as a surprise to anybody). As such, the benchmark is |
|
|
2001 | fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't |
|
|
2002 | very optimal. But how would AnyEvent compare when used without the extra |
|
|
2003 | baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. |
|
|
2004 | |
|
|
2005 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
2006 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
2007 | creates the next connection. This is a rather bad benchmark, as it doesn't |
|
|
2008 | test the efficiency of the framework or much non-blocking I/O, but it is a |
|
|
2009 | benchmark nevertheless. |
|
|
2010 | |
|
|
2011 | name runtime |
|
|
2012 | Lambda/select 0.330 sec |
|
|
2013 | + optimized 0.122 sec |
|
|
2014 | Lambda/AnyEvent 0.327 sec |
|
|
2015 | + optimized 0.138 sec |
|
|
2016 | Raw sockets/select 0.077 sec |
|
|
2017 | POE/select, components 0.662 sec |
|
|
2018 | POE/select, raw sockets 0.226 sec |
|
|
2019 | POE/select, optimized 0.404 sec |
|
|
2020 | |
|
|
2021 | AnyEvent/select/nb 0.085 sec |
|
|
2022 | AnyEvent/EV/nb 0.068 sec |
|
|
2023 | +state machine 0.134 sec |
|
|
2024 | |
|
|
2025 | The benchmark is also a bit unfair (my fault): the IO::Lambda/POE |
|
|
2026 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
2027 | defeating the purpose of an event-based solution. All of the newly |
|
|
2028 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
2029 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
2030 | resolver), so AnyEvent is at a disadvantage here, as non-blocking connects |
|
|
2031 | generally require a lot more bookkeeping and event handling than blocking |
|
|
2032 | connects (which involve a single syscall only). |
|
|
2033 | |
|
|
2034 | The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which |
|
|
2035 | offers similar expressive power as POE and IO::Lambda, using conventional |
|
|
2036 | Perl syntax. This means that both the echo server and the client are 100% |
|
|
2037 | non-blocking, further placing it at a disadvantage. |
|
|
2038 | |
|
|
2039 | As you can see, the AnyEvent + EV combination even beats the |
|
|
2040 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
|
|
2041 | backend easily beats IO::Lambda and POE. |
|
|
2042 | |
|
|
2043 | And even the 100% non-blocking version written using the high-level (and |
|
|
2044 | slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a |
|
|
2045 | large margin, even though it does all of DNS, tcp-connect and socket I/O |
|
|
2046 | in a non-blocking way. |
|
|
2047 | |
|
|
2048 | The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and |
|
|
2049 | F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are |
|
|
2050 | part of the IO::lambda distribution and were used without any changes. |
|
|
2051 | |
1892 | |
2052 | |
1893 | =head1 SIGNALS |
2053 | =head1 SIGNALS |
1894 | |
2054 | |
1895 | AnyEvent currently installs handlers for these signals: |
2055 | AnyEvent currently installs handlers for these signals: |
1896 | |
2056 | |
… | |
… | |
1899 | =item SIGCHLD |
2059 | =item SIGCHLD |
1900 | |
2060 | |
1901 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
2061 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
1902 | emulation for event loops that do not support them natively. Also, some |
2062 | emulation for event loops that do not support them natively. Also, some |
1903 | event loops install a similar handler. |
2063 | event loops install a similar handler. |
|
|
2064 | |
|
|
2065 | If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will |
|
|
2066 | reset it to default, to avoid losing child exit statuses. |
1904 | |
2067 | |
1905 | =item SIGPIPE |
2068 | =item SIGPIPE |
1906 | |
2069 | |
1907 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
2070 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
1908 | when AnyEvent gets loaded. |
2071 | when AnyEvent gets loaded. |
… | |
… | |
1920 | |
2083 | |
1921 | =back |
2084 | =back |
1922 | |
2085 | |
1923 | =cut |
2086 | =cut |
1924 | |
2087 | |
|
|
2088 | undef $SIG{CHLD} |
|
|
2089 | if $SIG{CHLD} eq 'IGNORE'; |
|
|
2090 | |
1925 | $SIG{PIPE} = sub { } |
2091 | $SIG{PIPE} = sub { } |
1926 | unless defined $SIG{PIPE}; |
2092 | unless defined $SIG{PIPE}; |
1927 | |
|
|
1928 | |
2093 | |
1929 | =head1 FORK |
2094 | =head1 FORK |
1930 | |
2095 | |
1931 | Most event libraries are not fork-safe. The ones who are usually are |
2096 | Most event libraries are not fork-safe. The ones who are usually are |
1932 | because they rely on inefficient but fork-safe C<select> or C<poll> |
2097 | because they rely on inefficient but fork-safe C<select> or C<poll> |
… | |
… | |
1953 | use AnyEvent; |
2118 | use AnyEvent; |
1954 | |
2119 | |
1955 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
2120 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1956 | be used to probe what backend is used and gain other information (which is |
2121 | be used to probe what backend is used and gain other information (which is |
1957 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
2122 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
1958 | $ENV{PERL_ANYEGENT_STRICT}. |
2123 | $ENV{PERL_ANYEVENT_STRICT}. |
|
|
2124 | |
|
|
2125 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
2126 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
2127 | enabled. |
1959 | |
2128 | |
1960 | |
2129 | |
1961 | =head1 BUGS |
2130 | =head1 BUGS |
1962 | |
2131 | |
1963 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
2132 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |