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Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.44 by root, Thu Apr 18 10:49:59 2013 UTC vs.
Revision 1.50 by root, Sat Apr 20 19:58:06 2013 UTC

… …
255=head1 CONCEPTS 255=head1 CONCEPTS
256 256
257This module can create new processes either by executing a new perl 257This module can create new processes either by executing a new perl
258process, or by forking from an existing "template" process. 258process, or by forking from an existing "template" process.
259 259
260All these processes are called "child processes" (whether they are direct
261children or not), while the process that manages them is called the
262"parent process".
263
260Each such process comes with its own file handle that can be used to 264Each such process comes with its own file handle that can be used to
261communicate with it (it's actually a socket - one end in the new process, 265communicate with it (it's actually a socket - one end in the new process,
262one end in the main process), and among the things you can do in it are 266one end in the main process), and among the things you can do in it are
263load modules, fork new processes, send file handles to it, and execute 267load modules, fork new processes, send file handles to it, and execute
264functions. 268functions.
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373use AnyEvent; 377use AnyEvent;
374use AnyEvent::Util (); 378use AnyEvent::Util ();
375 379
376use IO::FDPass; 380use IO::FDPass;
377 381
378our $VERSION = 0.6; 382our $VERSION = 0.7;
379 383
380# the early fork template process 384# the early fork template process
381our $EARLY; 385our $EARLY;
382 386
383# the empty template process 387# the empty template process
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431 # send string 435 # send string
432 my $len = syswrite $self->[FH], $self->[QUEUE][0]; 436 my $len = syswrite $self->[FH], $self->[QUEUE][0];
433 437
434 unless ($len) { 438 unless ($len) {
435 return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; 439 return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK;
436 undef $self->[3]; 440 undef $self->[WW];
437 die "AnyEvent::Fork: command write failure: $!"; 441 die "AnyEvent::Fork: command write failure: $!";
438 } 442 }
439 443
440 substr $self->[QUEUE][0], 0, $len, ""; 444 substr $self->[QUEUE][0], 0, $len, "";
441 shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; 445 shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];
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444 448
445 # everything written 449 # everything written
446 undef $self->[WW]; 450 undef $self->[WW];
447 451
448 # invoke run callback, if any 452 # invoke run callback, if any
453 if ($self->[CB]) {
449 $self->[CB]->($self->[FH]) if $self->[CB]; 454 $self->[CB]->($self->[FH]);
455 @$self = ();
456 }
450 }; 457 };
451 458
452 () # make sure we don't leak the watcher 459 () # make sure we don't leak the watcher
453} 460}
454 461
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767 774
768 $self->[CB] = $cb; 775 $self->[CB] = $cb;
769 $self->_cmd (r => $func); 776 $self->_cmd (r => $func);
770} 777}
771 778
779=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED
780
781Flushes all commands out to the process and then calls the callback with
782the communications socket.
783
784The process object becomes unusable on return from this function - any
785further method calls result in undefined behaviour.
786
787The point of this method is to give you a file handle thta you cna pass
788to another process. In that other process, you can call C<new_from_fh
789AnyEvent::Fork::RPC> to create a new C<AnyEvent::Fork> object from it,
790thereby effectively passing a fork object to another process.
791
792=cut
793
794sub to_fh {
795 my ($self, $cb) = @_;
796
797 $self->[CB] = $cb;
798
799 unless ($self->[WW]) {
800 $self->[CB]->($self->[FH]);
801 @$self = ();
802 }
803}
804
805=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED
806
807Takes a file handle originally rceeived by the C<to_fh> method and creates
808a new C<AnyEvent:Fork> object. The child process itself will not change in
809any way, i.e. it will keep all the modifications done to it before calling
810C<to_fh>.
811
812The new object is very much like the original object, except that the
813C<pid> method will return C<undef> even if the process is a direct child.
814
815=cut
816
817sub new_from_fh {
818 my ($class, $fh) = @_;
819
820 $class->_new ($fh)
821}
822
772=back 823=back
773 824
774=head1 PERFORMANCE 825=head1 PERFORMANCE
775 826
776Now for some unscientific benchmark numbers (all done on an amd64 827Now for some unscientific benchmark numbers (all done on an amd64
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784 835
785 2079 new processes per second, using manual socketpair + fork 836 2079 new processes per second, using manual socketpair + fork
786 837
787Then I did the same thing, but instead of calling fork, I called 838Then I did the same thing, but instead of calling fork, I called
788AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the 839AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the
789socket form the child to close on exit. This does the same thing as manual 840socket from the child to close on exit. This does the same thing as manual
790socket pair + fork, except that what is forked is the template process 841socket pair + fork, except that what is forked is the template process
791(2440kB), and the socket needs to be passed to the server at the other end 842(2440kB), and the socket needs to be passed to the server at the other end
792of the socket first. 843of the socket first.
793 844
794 2307 new processes per second, using AnyEvent::Fork->new 845 2307 new processes per second, using AnyEvent::Fork->new
… …
901to make it so, mostly due to the bloody broken perl that nobody seems to 952to make it so, mostly due to the bloody broken perl that nobody seems to
902care about. The fork emulation is a bad joke - I have yet to see something 953care about. The fork emulation is a bad joke - I have yet to see something
903useful that you can do with it without running into memory corruption 954useful that you can do with it without running into memory corruption
904issues or other braindamage. Hrrrr. 955issues or other braindamage. Hrrrr.
905 956
957Since fork is endlessly broken on win32 perls (it doesn't even remotely
958work within it's documented limits) and quite obviously it's not getting
959improved any time soon, the best way to proceed on windows would be to
960always use C<new_exec> and thus never rely on perl's fork "emulation".
961
906Cygwin perl is not supported at the moment due to some hilarious 962Cygwin perl is not supported at the moment due to some hilarious
907shortcomings of its API - see L<IO::FDPoll> for more details. 963shortcomings of its API - see L<IO::FDPoll> for more details. If you never
964use C<send_fh> and always use C<new_exec> to create processes, it should
965work though.
908 966
909=head1 SEE ALSO 967=head1 SEE ALSO
910 968
911L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), 969L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all
970(part of this distribution).
971
912L<AnyEvent::Fork::Template> (to create a process by forking the main 972L<AnyEvent::Fork::Template>, to create a process by forking the main
913program at a convenient time), L<AnyEvent::Fork::RPC> (for simple RPC to 973program at a convenient time (part of this distribution).
914child processes). 974
975L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).
915 976
916=head1 AUTHOR AND CONTACT INFORMATION 977=head1 AUTHOR AND CONTACT INFORMATION
917 978
918 Marc Lehmann <schmorp@schmorp.de> 979 Marc Lehmann <schmorp@schmorp.de>
919 http://software.schmorp.de/pkg/AnyEvent-Fork 980 http://software.schmorp.de/pkg/AnyEvent-Fork

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