… | |
… | |
38 | |
38 | |
39 | If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> |
39 | If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> |
40 | companion module, which adds simple RPC/job queueing to a process created |
40 | companion module, which adds simple RPC/job queueing to a process created |
41 | by this module. |
41 | by this module. |
42 | |
42 | |
|
|
43 | And if you need some automatic process pool management on top of |
|
|
44 | L<AnyEvent::Fork::RPC>, you can look at the L<AnyEvent::Fork::Pool> |
|
|
45 | companion module. |
|
|
46 | |
43 | Or you can implement it yourself in whatever way you like, use some |
47 | Or you can implement it yourself in whatever way you like: use some |
44 | message-passing module such as L<AnyEvent::MP>, some pipe such as |
48 | message-passing module such as L<AnyEvent::MP>, some pipe such as |
45 | L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send |
49 | L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send |
46 | e.g. JSON or Storable messages, and so on. |
50 | e.g. JSON or Storable messages, and so on. |
47 | |
51 | |
48 | =head2 COMPARISON TO OTHER MODULES |
52 | =head2 COMPARISON TO OTHER MODULES |
… | |
… | |
52 | or L<AnyEvent::Subprocess>. There are modules that implement their own |
56 | or L<AnyEvent::Subprocess>. There are modules that implement their own |
53 | process management, such as L<AnyEvent::DBI>. |
57 | process management, such as L<AnyEvent::DBI>. |
54 | |
58 | |
55 | The problems that all these modules try to solve are real, however, none |
59 | The problems that all these modules try to solve are real, however, none |
56 | of them (from what I have seen) tackle the very real problems of unwanted |
60 | of them (from what I have seen) tackle the very real problems of unwanted |
57 | memory sharing, efficiency, not being able to use event processing or |
61 | memory sharing, efficiency or not being able to use event processing, GUI |
58 | similar modules in the processes they create. |
62 | toolkits or similar modules in the processes they create. |
59 | |
63 | |
60 | This module doesn't try to replace any of them - instead it tries to solve |
64 | This module doesn't try to replace any of them - instead it tries to solve |
61 | the problem of creating processes with a minimum of fuss and overhead (and |
65 | the problem of creating processes with a minimum of fuss and overhead (and |
62 | also luxury). Ideally, most of these would use AnyEvent::Fork internally, |
66 | also luxury). Ideally, most of these would use AnyEvent::Fork internally, |
63 | except they were written before AnyEvent:Fork was available, so obviously |
67 | except they were written before AnyEvent:Fork was available, so obviously |
… | |
… | |
85 | |
89 | |
86 | =item Forking usually creates a copy-on-write copy of the parent |
90 | =item Forking usually creates a copy-on-write copy of the parent |
87 | process. |
91 | process. |
88 | |
92 | |
89 | For example, modules or data files that are loaded will not use additional |
93 | For example, modules or data files that are loaded will not use additional |
90 | memory after a fork. When exec'ing a new process, modules and data files |
94 | memory after a fork. Exec'ing a new process, in contrast, means modules |
91 | might need to be loaded again, at extra CPU and memory cost. But when |
95 | and data files might need to be loaded again, at extra CPU and memory |
92 | forking, literally all data structures are copied - if the program frees |
96 | cost. |
|
|
97 | |
|
|
98 | But when forking, you still create a copy of your data structures - if |
93 | them and replaces them by new data, the child processes will retain the |
99 | the program frees them and replaces them by new data, the child processes |
94 | old version even if it isn't used, which can suddenly and unexpectedly |
100 | will retain the old version even if it isn't used, which can suddenly and |
95 | increase memory usage when freeing memory. |
101 | unexpectedly increase memory usage when freeing memory. |
96 | |
102 | |
|
|
103 | For example, L<Gtk2::CV> is an image viewer optimised for large |
|
|
104 | directories (millions of pictures). It also forks subprocesses for |
|
|
105 | thumbnail generation, which inherit the data structure that stores all |
|
|
106 | file information. If the user changes the directory, it gets freed in |
|
|
107 | the main process, leaving a copy in the thumbnailer processes. This can |
|
|
108 | lead to many times the memory usage that would actually be required. The |
|
|
109 | solution is to fork early (and being unable to dynamically generate more |
|
|
110 | subprocesses or do this from a module)... or to use L<AnyEvent:Fork>. |
|
|
111 | |
97 | The trade-off is between more sharing with fork (which can be good or |
112 | There is a trade-off between more sharing with fork (which can be good or |
98 | bad), and no sharing with exec. |
113 | bad), and no sharing with exec. |
99 | |
114 | |
100 | This module allows the main program to do a controlled fork, and allows |
115 | This module allows the main program to do a controlled fork, and allows |
101 | modules to exec processes safely at any time. When creating a custom |
116 | modules to exec processes safely at any time. When creating a custom |
102 | process pool you can take advantage of data sharing via fork without |
117 | process pool you can take advantage of data sharing via fork without |
… | |
… | |
107 | shared and what isn't, at all times. |
122 | shared and what isn't, at all times. |
108 | |
123 | |
109 | =item Exec'ing a new perl process might be difficult. |
124 | =item Exec'ing a new perl process might be difficult. |
110 | |
125 | |
111 | For example, it is not easy to find the correct path to the perl |
126 | For example, it is not easy to find the correct path to the perl |
112 | interpreter - C<$^X> might not be a perl interpreter at all. |
127 | interpreter - C<$^X> might not be a perl interpreter at all. Worse, there |
|
|
128 | might not even be a perl binary installed on the system. |
113 | |
129 | |
114 | This module tries hard to identify the correct path to the perl |
130 | This module tries hard to identify the correct path to the perl |
115 | interpreter. With a cooperative main program, exec'ing the interpreter |
131 | interpreter. With a cooperative main program, exec'ing the interpreter |
116 | might not even be necessary, but even without help from the main program, |
132 | might not even be necessary, but even without help from the main program, |
117 | it will still work when used from a module. |
133 | it will still work when used from a module. |
… | |
… | |
123 | and modules are no longer loadable because they refer to a different |
139 | and modules are no longer loadable because they refer to a different |
124 | perl version, or parts of a distribution are newer than the ones already |
140 | perl version, or parts of a distribution are newer than the ones already |
125 | loaded. |
141 | loaded. |
126 | |
142 | |
127 | This module supports creating pre-initialised perl processes to be used as |
143 | This module supports creating pre-initialised perl processes to be used as |
128 | a template for new processes. |
144 | a template for new processes at a later time, e.g. for use in a process |
|
|
145 | pool. |
129 | |
146 | |
130 | =item Forking might be impossible when a program is running. |
147 | =item Forking might be impossible when a program is running. |
131 | |
148 | |
132 | For example, POSIX makes it almost impossible to fork from a |
149 | For example, POSIX makes it almost impossible to fork from a |
133 | multi-threaded program while doing anything useful in the child - in |
150 | multi-threaded program while doing anything useful in the child - in |
134 | fact, if your perl program uses POSIX threads (even indirectly via |
151 | fact, if your perl program uses POSIX threads (even indirectly via |
135 | e.g. L<IO::AIO> or L<threads>), you cannot call fork on the perl level |
152 | e.g. L<IO::AIO> or L<threads>), you cannot call fork on the perl level |
136 | anymore without risking corruption issues on a number of operating |
153 | anymore without risking memory corruption or worse on a number of |
137 | systems. |
154 | operating systems. |
138 | |
155 | |
139 | This module can safely fork helper processes at any time, by calling |
156 | This module can safely fork helper processes at any time, by calling |
140 | fork+exec in C, in a POSIX-compatible way (via L<Proc::FastSpawn>). |
157 | fork+exec in C, in a POSIX-compatible way (via L<Proc::FastSpawn>). |
141 | |
158 | |
142 | =item Parallel processing with fork might be inconvenient or difficult |
159 | =item Parallel processing with fork might be inconvenient or difficult |
… | |
… | |
161 | |
178 | |
162 | =back |
179 | =back |
163 | |
180 | |
164 | =head1 EXAMPLES |
181 | =head1 EXAMPLES |
165 | |
182 | |
|
|
183 | This is where the wall of text ends and code speaks. |
|
|
184 | |
166 | =head2 Create a single new process, tell it to run your worker function. |
185 | =head2 Create a single new process, tell it to run your worker function. |
167 | |
186 | |
168 | AnyEvent::Fork |
187 | AnyEvent::Fork |
169 | ->new |
188 | ->new |
170 | ->require ("MyModule") |
189 | ->require ("MyModule") |
… | |
… | |
181 | |
200 | |
182 | sub worker { |
201 | sub worker { |
183 | my ($slave_filehandle) = @_; |
202 | my ($slave_filehandle) = @_; |
184 | |
203 | |
185 | # now $slave_filehandle is connected to the $master_filehandle |
204 | # now $slave_filehandle is connected to the $master_filehandle |
186 | # in the original prorcess. have fun! |
205 | # in the original process. have fun! |
187 | } |
206 | } |
188 | |
207 | |
189 | =head2 Create a pool of server processes all accepting on the same socket. |
208 | =head2 Create a pool of server processes all accepting on the same socket. |
190 | |
209 | |
191 | # create listener socket |
210 | # create listener socket |
… | |
… | |
250 | ->send_arg ("/bin/echo", "hi") |
269 | ->send_arg ("/bin/echo", "hi") |
251 | ->run ("run", my $cv = AE::cv); |
270 | ->run ("run", my $cv = AE::cv); |
252 | |
271 | |
253 | my $stderr = $cv->recv; |
272 | my $stderr = $cv->recv; |
254 | |
273 | |
|
|
274 | =head2 For stingy users: put the worker code into a C<DATA> section. |
|
|
275 | |
|
|
276 | When you want to be stingy with files, you can put your code into the |
|
|
277 | C<DATA> section of your module (or program): |
|
|
278 | |
|
|
279 | use AnyEvent::Fork; |
|
|
280 | |
|
|
281 | AnyEvent::Fork |
|
|
282 | ->new |
|
|
283 | ->eval (do { local $/; <DATA> }) |
|
|
284 | ->run ("doit", sub { ... }); |
|
|
285 | |
|
|
286 | __DATA__ |
|
|
287 | |
|
|
288 | sub doit { |
|
|
289 | ... do something! |
|
|
290 | } |
|
|
291 | |
|
|
292 | =head2 For stingy standalone programs: do not rely on external files at |
|
|
293 | all. |
|
|
294 | |
|
|
295 | For single-file scripts it can be inconvenient to rely on external |
|
|
296 | files - even when using a C<DATA> section, you still need to C<exec> an |
|
|
297 | external perl interpreter, which might not be available when using |
|
|
298 | L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example. |
|
|
299 | |
|
|
300 | Two modules help here - L<AnyEvent::Fork::Early> forks a template process |
|
|
301 | for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template> |
|
|
302 | forks the main program as a template process. |
|
|
303 | |
|
|
304 | Here is how your main program should look like: |
|
|
305 | |
|
|
306 | #! perl |
|
|
307 | |
|
|
308 | # optional, as the very first thing. |
|
|
309 | # in case modules want to create their own processes. |
|
|
310 | use AnyEvent::Fork::Early; |
|
|
311 | |
|
|
312 | # next, load all modules you need in your template process |
|
|
313 | use Example::My::Module |
|
|
314 | use Example::Whatever; |
|
|
315 | |
|
|
316 | # next, put your run function definition and anything else you |
|
|
317 | # need, but do not use code outside of BEGIN blocks. |
|
|
318 | sub worker_run { |
|
|
319 | my ($fh, @args) = @_; |
|
|
320 | ... |
|
|
321 | } |
|
|
322 | |
|
|
323 | # now preserve everything so far as AnyEvent::Fork object |
|
|
324 | # in $TEMPLATE. |
|
|
325 | use AnyEvent::Fork::Template; |
|
|
326 | |
|
|
327 | # do not put code outside of BEGIN blocks until here |
|
|
328 | |
|
|
329 | # now use the $TEMPLATE process in any way you like |
|
|
330 | |
|
|
331 | # for example: create 10 worker processes |
|
|
332 | my @worker; |
|
|
333 | my $cv = AE::cv; |
|
|
334 | for (1..10) { |
|
|
335 | $cv->begin; |
|
|
336 | $TEMPLATE->fork->send_arg ($_)->run ("worker_run", sub { |
|
|
337 | push @worker, shift; |
|
|
338 | $cv->end; |
|
|
339 | }); |
|
|
340 | } |
|
|
341 | $cv->recv; |
|
|
342 | |
255 | =head1 CONCEPTS |
343 | =head1 CONCEPTS |
256 | |
344 | |
257 | This module can create new processes either by executing a new perl |
345 | This module can create new processes either by executing a new perl |
258 | process, or by forking from an existing "template" process. |
346 | process, or by forking from an existing "template" process. |
259 | |
347 | |
… | |
… | |
377 | use AnyEvent; |
465 | use AnyEvent; |
378 | use AnyEvent::Util (); |
466 | use AnyEvent::Util (); |
379 | |
467 | |
380 | use IO::FDPass; |
468 | use IO::FDPass; |
381 | |
469 | |
382 | our $VERSION = 0.6; |
470 | our $VERSION = 1.2; |
383 | |
471 | |
384 | # the early fork template process |
472 | # the early fork template process |
385 | our $EARLY; |
473 | our $EARLY; |
386 | |
474 | |
387 | # the empty template process |
475 | # the empty template process |
… | |
… | |
435 | # send string |
523 | # send string |
436 | my $len = syswrite $self->[FH], $self->[QUEUE][0]; |
524 | my $len = syswrite $self->[FH], $self->[QUEUE][0]; |
437 | |
525 | |
438 | unless ($len) { |
526 | unless ($len) { |
439 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
527 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
440 | undef $self->[3]; |
528 | undef $self->[WW]; |
441 | die "AnyEvent::Fork: command write failure: $!"; |
529 | die "AnyEvent::Fork: command write failure: $!"; |
442 | } |
530 | } |
443 | |
531 | |
444 | substr $self->[QUEUE][0], 0, $len, ""; |
532 | substr $self->[QUEUE][0], 0, $len, ""; |
445 | shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; |
533 | shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; |
… | |
… | |
448 | |
536 | |
449 | # everything written |
537 | # everything written |
450 | undef $self->[WW]; |
538 | undef $self->[WW]; |
451 | |
539 | |
452 | # invoke run callback, if any |
540 | # invoke run callback, if any |
|
|
541 | if ($self->[CB]) { |
453 | $self->[CB]->($self->[FH]) if $self->[CB]; |
542 | $self->[CB]->($self->[FH]); |
|
|
543 | @$self = (); |
|
|
544 | } |
454 | }; |
545 | }; |
455 | |
546 | |
456 | () # make sure we don't leak the watcher |
547 | () # make sure we don't leak the watcher |
457 | } |
548 | } |
458 | |
549 | |
… | |
… | |
529 | |
620 | |
530 | You should use C<new> whenever possible, except when having a template |
621 | You should use C<new> whenever possible, except when having a template |
531 | process around is unacceptable. |
622 | process around is unacceptable. |
532 | |
623 | |
533 | The path to the perl interpreter is divined using various methods - first |
624 | The path to the perl interpreter is divined using various methods - first |
534 | C<$^X> is investigated to see if the path ends with something that sounds |
625 | C<$^X> is investigated to see if the path ends with something that looks |
535 | as if it were the perl interpreter. Failing this, the module falls back to |
626 | as if it were the perl interpreter. Failing this, the module falls back to |
536 | using C<$Config::Config{perlpath}>. |
627 | using C<$Config::Config{perlpath}>. |
537 | |
628 | |
|
|
629 | The path to perl can also be overriden by setting the global variable |
|
|
630 | C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent |
|
|
631 | invocations. |
|
|
632 | |
538 | =cut |
633 | =cut |
|
|
634 | |
|
|
635 | our $PERL; |
539 | |
636 | |
540 | sub new_exec { |
637 | sub new_exec { |
541 | my ($self) = @_; |
638 | my ($self) = @_; |
542 | |
639 | |
543 | return $EARLY->fork |
640 | return $EARLY->fork |
544 | if $EARLY; |
641 | if $EARLY; |
545 | |
642 | |
|
|
643 | unless (defined $PERL) { |
546 | # first find path of perl |
644 | # first find path of perl |
547 | my $perl = $; |
645 | my $perl = $^X; |
548 | |
646 | |
549 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
647 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
550 | # that looks like perl. this obviously only works for posix and win32 |
648 | # that looks like perl. this obviously only works for posix and win32 |
551 | unless ( |
649 | unless ( |
552 | ($^O eq "MSWin32" || $perl =~ m%^/%) |
650 | ($^O eq "MSWin32" || $perl =~ m%^/%) |
553 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
651 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
554 | ) { |
652 | ) { |
555 | # if it doesn't look perlish enough, try Config |
653 | # if it doesn't look perlish enough, try Config |
556 | require Config; |
654 | require Config; |
557 | $perl = $Config::Config{perlpath}; |
655 | $perl = $Config::Config{perlpath}; |
558 | $perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/; |
656 | $perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/; |
|
|
657 | } |
|
|
658 | |
|
|
659 | $PERL = $perl; |
559 | } |
660 | } |
560 | |
661 | |
561 | require Proc::FastSpawn; |
662 | require Proc::FastSpawn; |
562 | |
663 | |
563 | my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
664 | my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
… | |
… | |
571 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
672 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
572 | my %env = %ENV; |
673 | my %env = %ENV; |
573 | $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
674 | $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
574 | |
675 | |
575 | my $pid = Proc::FastSpawn::spawn ( |
676 | my $pid = Proc::FastSpawn::spawn ( |
576 | $perl, |
677 | $PERL, |
577 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
678 | [$PERL, "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
578 | [map "$_=$env{$_}", keys %env], |
679 | [map "$_=$env{$_}", keys %env], |
579 | ) or die "unable to spawn AnyEvent::Fork server: $!"; |
680 | ) or die "unable to spawn AnyEvent::Fork server: $!"; |
580 | |
681 | |
581 | $self->_new ($fh, $pid) |
682 | $self->_new ($fh, $pid) |
582 | } |
683 | } |
583 | |
684 | |
584 | =item $pid = $proc->pid |
685 | =item $pid = $proc->pid |
585 | |
686 | |
586 | Returns the process id of the process I<iff it is a direct child of the |
687 | Returns the process id of the process I<iff it is a direct child of the |
587 | process running AnyEvent::Fork>, and C<undef> otherwise. |
688 | process running AnyEvent::Fork>, and C<undef> otherwise. As a general |
|
|
689 | rule (that you cannot rely upon), processes created via C<new_exec>, |
|
|
690 | L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template> are direct |
|
|
691 | children, while all other processes are not. |
588 | |
692 | |
589 | Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and |
693 | Or in other words, you do not normally have to take care of zombies for |
590 | L<AnyEvent::Fork::Template> are direct children, and you are responsible |
694 | processes created via C<new>, but when in doubt, or zombies are a problem, |
591 | to clean up their zombies when they die. |
695 | you need to check whether a process is a diretc child by calling this |
592 | |
696 | method, and possibly creating a child watcher or reap it manually. |
593 | All other processes are not direct children, and will be cleaned up by |
|
|
594 | AnyEvent::Fork itself. |
|
|
595 | |
697 | |
596 | =cut |
698 | =cut |
597 | |
699 | |
598 | sub pid { |
700 | sub pid { |
599 | $_[0][PID] |
701 | $_[0][PID] |
… | |
… | |
618 | C<send_xxx> methods, such as file handles. See the L<use AnyEvent::Fork as |
720 | C<send_xxx> methods, such as file handles. See the L<use AnyEvent::Fork as |
619 | a faster fork+exec> example to see it in action. |
721 | a faster fork+exec> example to see it in action. |
620 | |
722 | |
621 | Returns the process object for easy chaining of method calls. |
723 | Returns the process object for easy chaining of method calls. |
622 | |
724 | |
|
|
725 | It's common to want to call an iniitalisation function with some |
|
|
726 | arguments. Make sure you actually pass C<@_> to that function (for example |
|
|
727 | by using C<&name> syntax), and do not just specify a function name: |
|
|
728 | |
|
|
729 | $proc->eval ('&MyModule::init', $string1, $string2); |
|
|
730 | |
623 | =cut |
731 | =cut |
624 | |
732 | |
625 | sub eval { |
733 | sub eval { |
626 | my ($self, $code, @args) = @_; |
734 | my ($self, $code, @args) = @_; |
627 | |
735 | |
… | |
… | |
730 | |
838 | |
731 | Even if not used otherwise, the socket can be a good indicator for the |
839 | Even if not used otherwise, the socket can be a good indicator for the |
732 | existence of the process - if the other process exits, you get a readable |
840 | existence of the process - if the other process exits, you get a readable |
733 | event on it, because exiting the process closes the socket (if it didn't |
841 | event on it, because exiting the process closes the socket (if it didn't |
734 | create any children using fork). |
842 | create any children using fork). |
|
|
843 | |
|
|
844 | =over 4 |
|
|
845 | |
|
|
846 | =item Compatibility to L<AnyEvent::Fork::Remote> |
|
|
847 | |
|
|
848 | If you want to write code that works with both this module and |
|
|
849 | L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes |
|
|
850 | there are two file handles for communications, which might not be unix |
|
|
851 | domain sockets. The C<run> function should start like this: |
|
|
852 | |
|
|
853 | sub run { |
|
|
854 | my ($rfh, @args) = @_; # @args is your normal arguments |
|
|
855 | my $wfh = fileno $rfh ? $rfh : *STDOUT; |
|
|
856 | |
|
|
857 | # now use $rfh for reading and $wfh for writing |
|
|
858 | } |
|
|
859 | |
|
|
860 | This checks whether the passed file handle is, in fact, the process |
|
|
861 | C<STDIN> handle. If it is, then the function was invoked visa |
|
|
862 | L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and |
|
|
863 | C<STDOUT> should be used for writing. |
|
|
864 | |
|
|
865 | In all other cases, the function was called via this module, and there is |
|
|
866 | only one file handle that should be sued for reading and writing. |
|
|
867 | |
|
|
868 | =back |
735 | |
869 | |
736 | Example: create a template for a process pool, pass a few strings, some |
870 | Example: create a template for a process pool, pass a few strings, some |
737 | file handles, then fork, pass one more string, and run some code. |
871 | file handles, then fork, pass one more string, and run some code. |
738 | |
872 | |
739 | my $pool = AnyEvent::Fork |
873 | my $pool = AnyEvent::Fork |
… | |
… | |
773 | $self->_cmd (r => $func); |
907 | $self->_cmd (r => $func); |
774 | } |
908 | } |
775 | |
909 | |
776 | =back |
910 | =back |
777 | |
911 | |
|
|
912 | =head2 EXPERIMENTAL METHODS |
|
|
913 | |
|
|
914 | These methods might go away completely or change behaviour, at any time. |
|
|
915 | |
|
|
916 | =over 4 |
|
|
917 | |
|
|
918 | =item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
919 | |
|
|
920 | Flushes all commands out to the process and then calls the callback with |
|
|
921 | the communications socket. |
|
|
922 | |
|
|
923 | The process object becomes unusable on return from this function - any |
|
|
924 | further method calls result in undefined behaviour. |
|
|
925 | |
|
|
926 | The point of this method is to give you a file handle that you can pass |
|
|
927 | to another process. In that other process, you can call C<new_from_fh |
|
|
928 | AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it, |
|
|
929 | thereby effectively passing a fork object to another process. |
|
|
930 | |
|
|
931 | =cut |
|
|
932 | |
|
|
933 | sub to_fh { |
|
|
934 | my ($self, $cb) = @_; |
|
|
935 | |
|
|
936 | $self->[CB] = $cb; |
|
|
937 | |
|
|
938 | unless ($self->[WW]) { |
|
|
939 | $self->[CB]->($self->[FH]); |
|
|
940 | @$self = (); |
|
|
941 | } |
|
|
942 | } |
|
|
943 | |
|
|
944 | =item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
945 | |
|
|
946 | Takes a file handle originally rceeived by the C<to_fh> method and creates |
|
|
947 | a new C<AnyEvent:Fork> object. The child process itself will not change in |
|
|
948 | any way, i.e. it will keep all the modifications done to it before calling |
|
|
949 | C<to_fh>. |
|
|
950 | |
|
|
951 | The new object is very much like the original object, except that the |
|
|
952 | C<pid> method will return C<undef> even if the process is a direct child. |
|
|
953 | |
|
|
954 | =cut |
|
|
955 | |
|
|
956 | sub new_from_fh { |
|
|
957 | my ($class, $fh) = @_; |
|
|
958 | |
|
|
959 | $class->_new ($fh) |
|
|
960 | } |
|
|
961 | |
|
|
962 | =back |
|
|
963 | |
778 | =head1 PERFORMANCE |
964 | =head1 PERFORMANCE |
779 | |
965 | |
780 | Now for some unscientific benchmark numbers (all done on an amd64 |
966 | Now for some unscientific benchmark numbers (all done on an amd64 |
781 | GNU/Linux box). These are intended to give you an idea of the relative |
967 | GNU/Linux box). These are intended to give you an idea of the relative |
782 | performance you can expect, they are not meant to be absolute performance |
968 | performance you can expect, they are not meant to be absolute performance |
… | |
… | |
788 | |
974 | |
789 | 2079 new processes per second, using manual socketpair + fork |
975 | 2079 new processes per second, using manual socketpair + fork |
790 | |
976 | |
791 | Then I did the same thing, but instead of calling fork, I called |
977 | Then I did the same thing, but instead of calling fork, I called |
792 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
978 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
793 | socket form the child to close on exit. This does the same thing as manual |
979 | socket from the child to close on exit. This does the same thing as manual |
794 | socket pair + fork, except that what is forked is the template process |
980 | socket pair + fork, except that what is forked is the template process |
795 | (2440kB), and the socket needs to be passed to the server at the other end |
981 | (2440kB), and the socket needs to be passed to the server at the other end |
796 | of the socket first. |
982 | of the socket first. |
797 | |
983 | |
798 | 2307 new processes per second, using AnyEvent::Fork->new |
984 | 2307 new processes per second, using AnyEvent::Fork->new |
… | |
… | |
905 | to make it so, mostly due to the bloody broken perl that nobody seems to |
1091 | to make it so, mostly due to the bloody broken perl that nobody seems to |
906 | care about. The fork emulation is a bad joke - I have yet to see something |
1092 | care about. The fork emulation is a bad joke - I have yet to see something |
907 | useful that you can do with it without running into memory corruption |
1093 | useful that you can do with it without running into memory corruption |
908 | issues or other braindamage. Hrrrr. |
1094 | issues or other braindamage. Hrrrr. |
909 | |
1095 | |
|
|
1096 | Since fork is endlessly broken on win32 perls (it doesn't even remotely |
|
|
1097 | work within it's documented limits) and quite obviously it's not getting |
|
|
1098 | improved any time soon, the best way to proceed on windows would be to |
|
|
1099 | always use C<new_exec> and thus never rely on perl's fork "emulation". |
|
|
1100 | |
910 | Cygwin perl is not supported at the moment due to some hilarious |
1101 | Cygwin perl is not supported at the moment due to some hilarious |
911 | shortcomings of its API - see L<IO::FDPoll> for more details. |
1102 | shortcomings of its API - see L<IO::FDPoll> for more details. If you never |
|
|
1103 | use C<send_fh> and always use C<new_exec> to create processes, it should |
|
|
1104 | work though. |
|
|
1105 | |
|
|
1106 | =head1 USING AnyEvent::Fork IN SUBPROCESSES |
|
|
1107 | |
|
|
1108 | AnyEvent::Fork itself cannot generally be used in subprocesses. As long as |
|
|
1109 | only one process ever forks new processes, sharing the template processes |
|
|
1110 | is possible (you could use a pipe as a lock by writing a byte into it to |
|
|
1111 | unlock, and reading the byte to lock for example) |
|
|
1112 | |
|
|
1113 | To make concurrent calls possible after fork, you should get rid of the |
|
|
1114 | template and early fork processes. AnyEvent::Fork will create a new |
|
|
1115 | template process as needed. |
|
|
1116 | |
|
|
1117 | undef $AnyEvent::Fork::EARLY; |
|
|
1118 | undef $AnyEvent::Fork::TEMPLATE; |
|
|
1119 | |
|
|
1120 | It doesn't matter whether you get rid of them in the parent or child after |
|
|
1121 | a fork. |
912 | |
1122 | |
913 | =head1 SEE ALSO |
1123 | =head1 SEE ALSO |
914 | |
1124 | |
915 | L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
1125 | L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
916 | (part of this distribution). |
1126 | (part of this distribution). |
917 | |
1127 | |
918 | L<AnyEvent::Fork::Template>, to create a process by forking the main |
1128 | L<AnyEvent::Fork::Template>, to create a process by forking the main |
919 | program at a convenient time (part of this distribution). |
1129 | program at a convenient time (part of this distribution). |
920 | |
1130 | |
|
|
1131 | L<AnyEvent::Fork::Remote>, for another way to create processes that is |
|
|
1132 | mostly compatible to this module and modules building on top of it, but |
|
|
1133 | works better with remote processes. |
|
|
1134 | |
921 | L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
1135 | L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
|
|
1136 | |
|
|
1137 | L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN). |
922 | |
1138 | |
923 | =head1 AUTHOR AND CONTACT INFORMATION |
1139 | =head1 AUTHOR AND CONTACT INFORMATION |
924 | |
1140 | |
925 | Marc Lehmann <schmorp@schmorp.de> |
1141 | Marc Lehmann <schmorp@schmorp.de> |
926 | http://software.schmorp.de/pkg/AnyEvent-Fork |
1142 | http://software.schmorp.de/pkg/AnyEvent-Fork |