[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC vs.
Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC

 =head2 I/O WATCHERS
 You can create an I/O watcher by calling the C<< AnyEvent->io >> method
 with the following mandatory key-value pairs as arguments:
-C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
+C<fh> is the Perl I<file handle> (I<not> file descriptor, see below) to
-for events (AnyEvent might or might not keep a reference to this file
+watch for events (AnyEvent might or might not keep a reference to this
-handle). Note that only file handles pointing to things for which
+file handle). Note that only file handles pointing to things for which
 non-blocking operation makes sense are allowed. This includes sockets,
 most character devices, pipes, fifos and so on, but not for example files
 or block devices.
 C<poll> must be a string that is either C<r> or C<w>, which creates a
    my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
       chomp (my $input = <STDIN>);
       warn "read: $input\n";
       undef $w;
    });
+=head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR
+It is not uncommon to only have a file descriptor, while AnyEvent requires
+a Perl file handle.
+There are basically two methods to convert a file descriptor into a file handle. If you own
+the file descriptor, you can open it with C<&=>, as in:
+   open my $fh, "<&=$fileno" or die "xxx: §!";
+This will "own" the file descriptor, meaning that when C<$fh> is
+destroyed, it will automatically close the C<$fileno>. Also, note that
+the open mode (read, write, read/write) must correspond with how the
+underlying file descriptor was opened.
+In many cases, taking over the file descriptor is now what you want, in
+which case the only alternative is to dup the file descriptor:
+   open my $fh, "<&$fileno" or die "xxx: $!";
+This has the advantage of not closing the file descriptor and the
+disadvantage of making a slow copy.
 =head2 TIME WATCHERS
 You can create a time watcher by calling the C<< AnyEvent->timer >>
 method with the following mandatory arguments:
 =item $cv->begin ([group callback])
 =item $cv->end
-These two methods are EXPERIMENTAL and MIGHT CHANGE.
 These two methods can be used to combine many transactions/events into
 one. For example, a function that pings many hosts in parallel might want
 to use a condition variable for the whole process.
 Every call to C<< ->begin >> will increment a counter, and every call to
 C<< ->end >> will decrement it.  If the counter reaches C<0> in C<< ->end
 >>, the (last) callback passed to C<begin> will be executed. That callback
 is I<supposed> to call C<< ->send >>, but that is not required. If no
 callback was set, C<send> will be called without any arguments.
-Let's clarify this with the ping example:
+You can think of C<< $cv->send >> giving you an OR condition (one call
+sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
+condition (all C<begin> calls must be C<end>'ed before the condvar sends).
+Let's start with a simple example: you have two I/O watchers (for example,
+STDOUT and STDERR for a program), and you want to wait for both streams to
+close before activating a condvar:
+   my $cv = AnyEvent->condvar;
+   $cv->begin; # first watcher
+   my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
+      defined sysread $fh1, my $buf, 4096
+         or $cv->end;
+   });
+   $cv->begin; # second watcher
+   my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
+      defined sysread $fh2, my $buf, 4096
+         or $cv->end;
+   });
+   $cv->recv;
+This works because for every event source (EOF on file handle), there is
+one call to C<begin>, so the condvar waits for all calls to C<end> before
+sending.
+The ping example mentioned above is slightly more complicated, as the
+there are results to be passwd back, and the number of tasks that are
+begung can potentially be zero:
    my $cv = AnyEvent->condvar;
    my %result;
    $cv->begin (sub { $cv->send (\%result) });
 loop, which serves two important purposes: first, it sets the callback
 to be called once the counter reaches C<0>, and second, it ensures that
 C<send> is called even when C<no> hosts are being pinged (the loop
 doesn't execute once).
-This is the general pattern when you "fan out" into multiple subrequests:
+This is the general pattern when you "fan out" into multiple (but
-use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
+potentially none) subrequests: use an outer C<begin>/C<end> pair to set
-is called at least once, and then, for each subrequest you start, call
+the callback and ensure C<end> is called at least once, and then, for each
-C<begin> and for each subrequest you finish, call C<end>.
+subrequest you start, call C<begin> and for each subrequest you finish,
+call C<end>.
 =back
 =head3 METHODS FOR CONSUMERS
 no warnings;
 use strict qw(vars subs);
 use Carp;
-our $VERSION = 4.412;
+our $VERSION = 4.8;
 our $MODEL;
 our $AUTOLOAD;
 our @ISA;
 =item C<PERL_ANYEVENT_MAX_FORKS>
 The maximum number of child processes that C<AnyEvent::Util::fork_call>
 will create in parallel.
+=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
+The default value for the C<max_outstanding> parameter for the default DNS
+resolver - this is the maximum number of parallel DNS requests that are
+sent to the DNS server.
+=item C<PERL_ANYEVENT_RESOLV_CONF>
+The file to use instead of F</etc/resolv.conf> (or OS-specific
+configuration) in the default resolver. When set to the empty string, no
+default config will be used.
+=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
+When neither C<ca_file> nor C<ca_path> was specified during
+L<AnyEvent::TLS> context creation, and either of these environment
+variables exist, they will be used to specify CA certificate locations
+instead of a system-dependent default.
 =back
 =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
 This is an advanced topic that you do not normally need to use AnyEvent in
         EV/Any   100000   224   2.88   0.34    0.27 EV + AnyEvent watchers
     CoroEV/Any   100000   224   2.85   0.35    0.28 coroutines + Coro::Signal
       Perl/Any   100000   452   4.13   0.73    0.95 pure perl implementation
    Event/Event    16000   517  32.20  31.80    0.81 Event native interface
      Event/Any    16000   590  35.85  31.55    1.06 Event + AnyEvent watchers
+   IOAsync/Any    16000   989  38.10  32.77   11.13 via IO::Async::Loop::IO_Poll
+   IOAsync/Any    16000   990  37.59  29.50   10.61 via IO::Async::Loop::Epoll
       Glib/Any    16000  1357 102.33  12.31   51.00 quadratic behaviour
         Tk/Any     2000  1860  27.20  66.31   14.00 SEGV with >> 2000 watchers
      POE/Event     2000  6328 109.99 751.67   14.02 via POE::Loop::Event
     POE/Select     2000  6027  94.54 809.13  579.80 via POE::Loop::Select
 performance becomes really bad with lots of file descriptors (and few of
 them active), of course, but this was not subject of this benchmark.
 The C<Event> module has a relatively high setup and callback invocation
 cost, but overall scores in on the third place.
+C<IO::Async> performs admirably well, about on par with C<Event>, even
+when using its pure perl backend.
 C<Glib>'s memory usage is quite a bit higher, but it features a
 faster callback invocation and overall ends up in the same class as
 C<Event>. However, Glib scales extremely badly, doubling the number of
 watchers increases the processing time by more than a factor of four,
 it to another server. This includes deleting the old timeout and creating
 a new one that moves the timeout into the future.
 =head3 Results
-    name sockets create  request
+     name sockets create  request
-      EV   20000  69.01    11.16
+       EV   20000  69.01    11.16
-    Perl   20000  73.32    35.87
+     Perl   20000  73.32    35.87
+  IOAsync   20000 157.00    98.14 epoll
+  IOAsync   20000 159.31   616.06 poll
-   Event   20000 212.62   257.32
+    Event   20000 212.62   257.32
-    Glib   20000 651.16  1896.30
+     Glib   20000 651.16  1896.30
-     POE   20000 349.67 12317.24 uses POE::Loop::Event
+      POE   20000 349.67 12317.24 uses POE::Loop::Event
 =head3 Discussion
 This benchmark I<does> measure scalability and overall performance of the
 particular event loop.
 EV is again fastest. Since it is using epoll on my system, the setup time
 is relatively high, though.
 Perl surprisingly comes second. It is much faster than the C-based event
 loops Event and Glib.
+IO::Async performs very well when using its epoll backend, and still quite
+good compared to Glib when using its pure perl backend.
 Event suffers from high setup time as well (look at its code and you will
 understand why). Callback invocation also has a high overhead compared to
 the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
 uses select or poll in basically all documented configurations.

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC vs. Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC vs.
Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC