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34 | This module only creates processes and lets you pass file handles and |
34 | This module only creates processes and lets you pass file handles and |
35 | strings to it, and run perl code. It does not implement any kind of RPC - |
35 | strings to it, and run perl code. It does not implement any kind of RPC - |
36 | there is no back channel from the process back to you, and there is no RPC |
36 | there is no back channel from the process back to you, and there is no RPC |
37 | or message passing going on. |
37 | or message passing going on. |
38 | |
38 | |
39 | If you need some form of RPC, you can either implement it yourself |
39 | If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> |
40 | in whatever way you like, use some message-passing module such |
40 | companion module, which adds simple RPC/job queueing to a process created |
41 | as L<AnyEvent::MP>, some pipe such as L<AnyEvent::ZeroMQ>, use |
41 | by this module. |
42 | L<AnyEvent::Handle> on both sides to send e.g. JSON or Storable messages, |
42 | |
43 | and so on. |
43 | Or you can implement it yourself in whatever way you like, use some |
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44 | message-passing module such as L<AnyEvent::MP>, some pipe such as |
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45 | L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send |
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46 | e.g. JSON or Storable messages, and so on. |
44 | |
47 | |
45 | =head2 COMPARISON TO OTHER MODULES |
48 | =head2 COMPARISON TO OTHER MODULES |
46 | |
49 | |
47 | There is an abundance of modules on CPAN that do "something fork", such as |
50 | There is an abundance of modules on CPAN that do "something fork", such as |
48 | L<Parallel::ForkManager>, L<AnyEvent::ForkManager>, L<AnyEvent::Worker> |
51 | L<Parallel::ForkManager>, L<AnyEvent::ForkManager>, L<AnyEvent::Worker> |
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230 | open my $output, ">/tmp/log" or die "$!"; |
233 | open my $output, ">/tmp/log" or die "$!"; |
231 | |
234 | |
232 | AnyEvent::Fork |
235 | AnyEvent::Fork |
233 | ->new |
236 | ->new |
234 | ->eval (' |
237 | ->eval (' |
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238 | # compile a helper function for later use |
235 | sub run { |
239 | sub run { |
236 | my ($fh, $output, @cmd) = @_; |
240 | my ($fh, $output, @cmd) = @_; |
237 | |
241 | |
238 | # perl will clear close-on-exec on STDOUT/STDERR |
242 | # perl will clear close-on-exec on STDOUT/STDERR |
239 | open STDOUT, ">&", $output or die; |
243 | open STDOUT, ">&", $output or die; |
… | |
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369 | use AnyEvent; |
373 | use AnyEvent; |
370 | use AnyEvent::Util (); |
374 | use AnyEvent::Util (); |
371 | |
375 | |
372 | use IO::FDPass; |
376 | use IO::FDPass; |
373 | |
377 | |
374 | our $VERSION = 0.5; |
378 | our $VERSION = 0.6; |
375 | |
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376 | our $PERL; # the path to the perl interpreter, deduces with various forms of magic |
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377 | |
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378 | =over 4 |
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379 | |
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380 | =back |
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381 | |
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382 | =cut |
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383 | |
379 | |
384 | # the early fork template process |
380 | # the early fork template process |
385 | our $EARLY; |
381 | our $EARLY; |
386 | |
382 | |
387 | # the empty template process |
383 | # the empty template process |
388 | our $TEMPLATE; |
384 | our $TEMPLATE; |
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385 | |
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386 | sub QUEUE() { 0 } |
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387 | sub FH() { 1 } |
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388 | sub WW() { 2 } |
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389 | sub PID() { 3 } |
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390 | sub CB() { 4 } |
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391 | |
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392 | sub _new { |
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393 | my ($self, $fh, $pid) = @_; |
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394 | |
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395 | AnyEvent::Util::fh_nonblocking $fh, 1; |
|
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396 | |
|
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397 | $self = bless [ |
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398 | [], # write queue - strings or fd's |
|
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399 | $fh, |
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400 | undef, # AE watcher |
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401 | $pid, |
|
|
402 | ], $self; |
|
|
403 | |
|
|
404 | $self |
|
|
405 | } |
389 | |
406 | |
390 | sub _cmd { |
407 | sub _cmd { |
391 | my $self = shift; |
408 | my $self = shift; |
392 | |
409 | |
393 | # ideally, we would want to use "a (w/a)*" as format string, but perl |
410 | # ideally, we would want to use "a (w/a)*" as format string, but perl |
394 | # versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack |
411 | # versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack |
395 | # it. |
412 | # it. |
396 | push @{ $self->[2] }, pack "a L/a*", $_[0], $_[1]; |
413 | push @{ $self->[QUEUE] }, pack "a L/a*", $_[0], $_[1]; |
397 | |
414 | |
398 | $self->[3] ||= AE::io $self->[1], 1, sub { |
415 | $self->[WW] ||= AE::io $self->[FH], 1, sub { |
399 | do { |
416 | do { |
400 | # send the next "thing" in the queue - either a reference to an fh, |
417 | # send the next "thing" in the queue - either a reference to an fh, |
401 | # or a plain string. |
418 | # or a plain string. |
402 | |
419 | |
403 | if (ref $self->[2][0]) { |
420 | if (ref $self->[QUEUE][0]) { |
404 | # send fh |
421 | # send fh |
405 | unless (IO::FDPass::send fileno $self->[1], fileno ${ $self->[2][0] }) { |
422 | unless (IO::FDPass::send fileno $self->[FH], fileno ${ $self->[QUEUE][0] }) { |
406 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
423 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
407 | undef $self->[3]; |
424 | undef $self->[WW]; |
408 | die "AnyEvent::Fork: file descriptor send failure: $!"; |
425 | die "AnyEvent::Fork: file descriptor send failure: $!"; |
409 | } |
426 | } |
410 | |
427 | |
411 | shift @{ $self->[2] }; |
428 | shift @{ $self->[QUEUE] }; |
412 | |
429 | |
413 | } else { |
430 | } else { |
414 | # send string |
431 | # send string |
415 | my $len = syswrite $self->[1], $self->[2][0]; |
432 | my $len = syswrite $self->[FH], $self->[QUEUE][0]; |
416 | |
433 | |
417 | unless ($len) { |
434 | unless ($len) { |
418 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
435 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
419 | undef $self->[3]; |
436 | undef $self->[3]; |
420 | die "AnyEvent::Fork: command write failure: $!"; |
437 | die "AnyEvent::Fork: command write failure: $!"; |
421 | } |
438 | } |
422 | |
439 | |
423 | substr $self->[2][0], 0, $len, ""; |
440 | substr $self->[QUEUE][0], 0, $len, ""; |
424 | shift @{ $self->[2] } unless length $self->[2][0]; |
441 | shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; |
425 | } |
442 | } |
426 | } while @{ $self->[2] }; |
443 | } while @{ $self->[QUEUE] }; |
427 | |
444 | |
428 | # everything written |
445 | # everything written |
429 | undef $self->[3]; |
446 | undef $self->[WW]; |
430 | |
447 | |
431 | # invoke run callback, if any |
448 | # invoke run callback, if any |
432 | $self->[4]->($self->[1]) if $self->[4]; |
449 | $self->[CB]->($self->[FH]) if $self->[CB]; |
433 | }; |
450 | }; |
434 | |
451 | |
435 | () # make sure we don't leak the watcher |
452 | () # make sure we don't leak the watcher |
436 | } |
|
|
437 | |
|
|
438 | sub _new { |
|
|
439 | my ($self, $fh, $pid) = @_; |
|
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440 | |
|
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441 | AnyEvent::Util::fh_nonblocking $fh, 1; |
|
|
442 | |
|
|
443 | $self = bless [ |
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444 | $pid, |
|
|
445 | $fh, |
|
|
446 | [], # write queue - strings or fd's |
|
|
447 | undef, # AE watcher |
|
|
448 | ], $self; |
|
|
449 | |
|
|
450 | $self |
|
|
451 | } |
453 | } |
452 | |
454 | |
453 | # fork template from current process, used by AnyEvent::Fork::Early/Template |
455 | # fork template from current process, used by AnyEvent::Fork::Early/Template |
454 | sub _new_fork { |
456 | sub _new_fork { |
455 | my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
457 | my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
… | |
… | |
460 | if ($pid eq 0) { |
462 | if ($pid eq 0) { |
461 | require AnyEvent::Fork::Serve; |
463 | require AnyEvent::Fork::Serve; |
462 | $AnyEvent::Fork::Serve::OWNER = $parent; |
464 | $AnyEvent::Fork::Serve::OWNER = $parent; |
463 | close $fh; |
465 | close $fh; |
464 | $0 = "$_[1] of $parent"; |
466 | $0 = "$_[1] of $parent"; |
465 | $SIG{CHLD} = 'IGNORE'; |
|
|
466 | AnyEvent::Fork::Serve::serve ($slave); |
467 | AnyEvent::Fork::Serve::serve ($slave); |
467 | exit 0; |
468 | exit 0; |
468 | } elsif (!$pid) { |
469 | } elsif (!$pid) { |
469 | die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
470 | die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
470 | } |
471 | } |
… | |
… | |
589 | AnyEvent::Fork itself. |
590 | AnyEvent::Fork itself. |
590 | |
591 | |
591 | =cut |
592 | =cut |
592 | |
593 | |
593 | sub pid { |
594 | sub pid { |
594 | $_[0][0] |
595 | $_[0][PID] |
595 | } |
596 | } |
596 | |
597 | |
597 | =item $proc = $proc->eval ($perlcode, @args) |
598 | =item $proc = $proc->eval ($perlcode, @args) |
598 | |
599 | |
599 | Evaluates the given C<$perlcode> as ... perl code, while setting C<@_> to |
600 | Evaluates the given C<$perlcode> as ... perl code, while setting C<@_> to |
… | |
… | |
666 | sub send_fh { |
667 | sub send_fh { |
667 | my ($self, @fh) = @_; |
668 | my ($self, @fh) = @_; |
668 | |
669 | |
669 | for my $fh (@fh) { |
670 | for my $fh (@fh) { |
670 | $self->_cmd ("h"); |
671 | $self->_cmd ("h"); |
671 | push @{ $self->[2] }, \$fh; |
672 | push @{ $self->[QUEUE] }, \$fh; |
672 | } |
673 | } |
673 | |
674 | |
674 | $self |
675 | $self |
675 | } |
676 | } |
676 | |
677 | |
… | |
… | |
762 | =cut |
763 | =cut |
763 | |
764 | |
764 | sub run { |
765 | sub run { |
765 | my ($self, $func, $cb) = @_; |
766 | my ($self, $func, $cb) = @_; |
766 | |
767 | |
767 | $self->[4] = $cb; |
768 | $self->[CB] = $cb; |
768 | $self->_cmd (r => $func); |
769 | $self->_cmd (r => $func); |
769 | } |
770 | } |
770 | |
771 | |
771 | =back |
772 | =back |
772 | |
773 | |
… | |
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800 | So how can C<< AnyEvent->new >> be faster than a standard fork, even |
801 | So how can C<< AnyEvent->new >> be faster than a standard fork, even |
801 | though it uses the same operations, but adds a lot of overhead? |
802 | though it uses the same operations, but adds a lot of overhead? |
802 | |
803 | |
803 | The difference is simply the process size: forking the 5MB process takes |
804 | The difference is simply the process size: forking the 5MB process takes |
804 | so much longer than forking the 2.5MB template process that the extra |
805 | so much longer than forking the 2.5MB template process that the extra |
805 | overhead introduced is canceled out. |
806 | overhead is canceled out. |
806 | |
807 | |
807 | If the benchmark process grows, the normal fork becomes even slower: |
808 | If the benchmark process grows, the normal fork becomes even slower: |
808 | |
809 | |
809 | 1340 new processes, manual fork of a 20MB process |
810 | 1340 new processes, manual fork of a 20MB process |
810 | 731 new processes, manual fork of a 200MB process |
811 | 731 new processes, manual fork of a 200MB process |
… | |
… | |
909 | |
910 | |
910 | L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), |
911 | L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), |
911 | L<AnyEvent::Fork::Template> (to create a process by forking the main |
912 | L<AnyEvent::Fork::Template> (to create a process by forking the main |
912 | program at a convenient time). |
913 | program at a convenient time). |
913 | |
914 | |
914 | =head1 AUTHOR |
915 | =head1 AUTHOR AND CONTACT INFORMATION |
915 | |
916 | |
916 | Marc Lehmann <schmorp@schmorp.de> |
917 | Marc Lehmann <schmorp@schmorp.de> |
917 | http://home.schmorp.de/ |
918 | http://software.schmorp.de/pkg/AnyEvent-Fork |
918 | |
919 | |
919 | =cut |
920 | =cut |
920 | |
921 | |
921 | 1 |
922 | 1 |
922 | |
923 | |