1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent::Fork - everything you wanted to use fork() for, but couldn't |
3 | AnyEvent::Fork - everything you wanted to use fork() for, but couldn't |
4 | |
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5 | ATTENTION, this is a very early release, and very untested. Consider it a |
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6 | technology preview. |
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7 | |
4 | |
8 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
9 | |
6 | |
10 | use AnyEvent::Fork; |
7 | use AnyEvent::Fork; |
11 | |
8 | |
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73 | preserving most of the advantages of fork. |
70 | preserving most of the advantages of fork. |
74 | |
71 | |
75 | It can be used to create new worker processes or new independent |
72 | It can be used to create new worker processes or new independent |
76 | subprocesses for short- and long-running jobs, process pools (e.g. for use |
73 | subprocesses for short- and long-running jobs, process pools (e.g. for use |
77 | in pre-forked servers) but also to spawn new external processes (such as |
74 | in pre-forked servers) but also to spawn new external processes (such as |
78 | CGI scripts from a webserver), which can be faster (and more well behaved) |
75 | CGI scripts from a web server), which can be faster (and more well behaved) |
79 | than using fork+exec in big processes. |
76 | than using fork+exec in big processes. |
80 | |
77 | |
81 | Special care has been taken to make this module useful from other modules, |
78 | Special care has been taken to make this module useful from other modules, |
82 | while still supporting specialised environments such as L<App::Staticperl> |
79 | while still supporting specialised environments such as L<App::Staticperl> |
83 | or L<PAR::Packer>. |
80 | or L<PAR::Packer>. |
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81 | |
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82 | =head1 WHAT THIS MODULE IS NOT |
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83 | |
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84 | This module only creates processes and lets you pass file handles and |
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85 | strings to it, and run perl code. It does not implement any kind of RPC - |
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86 | there is no back channel from the process back to you, and there is no RPC |
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87 | or message passing going on. |
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88 | |
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89 | If you need some form of RPC, you can either implement it yourself |
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90 | in whatever way you like, use some message-passing module such |
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91 | as L<AnyEvent::MP>, some pipe such as L<AnyEvent::ZeroMQ>, use |
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92 | L<AnyEvent::Handle> on both sides to send e.g. JSON or Storable messages, |
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93 | and so on. |
84 | |
94 | |
85 | =head1 PROBLEM STATEMENT |
95 | =head1 PROBLEM STATEMENT |
86 | |
96 | |
87 | There are two ways to implement parallel processing on UNIX like operating |
97 | There are two ways to implement parallel processing on UNIX like operating |
88 | systems - fork and process, and fork+exec and process. They have different |
98 | systems - fork and process, and fork+exec and process. They have different |
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100 | or fork+exec instead. |
110 | or fork+exec instead. |
101 | |
111 | |
102 | =item Forking usually creates a copy-on-write copy of the parent |
112 | =item Forking usually creates a copy-on-write copy of the parent |
103 | process. Memory (for example, modules or data files that have been |
113 | process. Memory (for example, modules or data files that have been |
104 | will not take additional memory). When exec'ing a new process, modules |
114 | will not take additional memory). When exec'ing a new process, modules |
105 | and data files might need to be loaded again, at extra cpu and memory |
115 | and data files might need to be loaded again, at extra CPU and memory |
106 | cost. Likewise when forking, all data structures are copied as well - if |
116 | cost. Likewise when forking, all data structures are copied as well - if |
107 | the program frees them and replaces them by new data, the child processes |
117 | the program frees them and replaces them by new data, the child processes |
108 | will retain the memory even if it isn't used. |
118 | will retain the memory even if it isn't used. |
109 | |
119 | |
110 | This module allows the main program to do a controlled fork, and allows |
120 | This module allows the main program to do a controlled fork, and allows |
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122 | as template, and also tries hard to identify the correct path to the perl |
132 | as template, and also tries hard to identify the correct path to the perl |
123 | interpreter. With a cooperative main program, exec'ing the interpreter |
133 | interpreter. With a cooperative main program, exec'ing the interpreter |
124 | might not even be necessary. |
134 | might not even be necessary. |
125 | |
135 | |
126 | =item Forking might be impossible when a program is running. For example, |
136 | =item Forking might be impossible when a program is running. For example, |
127 | POSIX makes it almost impossible to fork from a multithreaded program and |
137 | POSIX makes it almost impossible to fork from a multi-threaded program and |
128 | do anything useful in the child - strictly speaking, if your perl program |
138 | do anything useful in the child - strictly speaking, if your perl program |
129 | uses posix threads (even indirectly via e.g. L<IO::AIO> or L<threads>), |
139 | uses posix threads (even indirectly via e.g. L<IO::AIO> or L<threads>), |
130 | you cannot call fork on the perl level anymore, at all. |
140 | you cannot call fork on the perl level anymore, at all. |
131 | |
141 | |
132 | This module can safely fork helper processes at any time, by caling |
142 | This module can safely fork helper processes at any time, by calling |
133 | fork+exec in C, in a POSIX-compatible way. |
143 | fork+exec in C, in a POSIX-compatible way. |
134 | |
144 | |
135 | =item Parallel processing with fork might be inconvenient or difficult |
145 | =item Parallel processing with fork might be inconvenient or difficult |
136 | to implement. For example, when a program uses an event loop and creates |
146 | to implement. For example, when a program uses an event loop and creates |
137 | watchers it becomes very hard to use the event loop from a child |
147 | watchers it becomes very hard to use the event loop from a child |
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169 | needed the first time. Forking from this process shares the memory used |
179 | needed the first time. Forking from this process shares the memory used |
170 | for the perl interpreter with the new process, but loading modules takes |
180 | for the perl interpreter with the new process, but loading modules takes |
171 | time, and the memory is not shared with anything else. |
181 | time, and the memory is not shared with anything else. |
172 | |
182 | |
173 | This is ideal for when you only need one extra process of a kind, with the |
183 | This is ideal for when you only need one extra process of a kind, with the |
174 | option of starting and stipping it on demand. |
184 | option of starting and stopping it on demand. |
175 | |
185 | |
176 | Example: |
186 | Example: |
177 | |
187 | |
178 | AnyEvent::Fork |
188 | AnyEvent::Fork |
179 | ->new |
189 | ->new |
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194 | modules you loaded) is shared between the processes, and each new process |
204 | modules you loaded) is shared between the processes, and each new process |
195 | consumes relatively little memory of its own. |
205 | consumes relatively little memory of its own. |
196 | |
206 | |
197 | The disadvantage of this approach is that you need to create a template |
207 | The disadvantage of this approach is that you need to create a template |
198 | process for the sole purpose of forking new processes from it, but if you |
208 | process for the sole purpose of forking new processes from it, but if you |
199 | only need a fixed number of proceses you can create them, and then destroy |
209 | only need a fixed number of processes you can create them, and then destroy |
200 | the template process. |
210 | the template process. |
201 | |
211 | |
202 | Example: |
212 | Example: |
203 | |
213 | |
204 | my $template = AnyEvent::Fork->new->require ("Some::Module"); |
214 | my $template = AnyEvent::Fork->new->require ("Some::Module"); |
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241 | |
251 | |
242 | package AnyEvent::Fork; |
252 | package AnyEvent::Fork; |
243 | |
253 | |
244 | use common::sense; |
254 | use common::sense; |
245 | |
255 | |
246 | use Socket (); |
256 | use Errno (); |
247 | |
257 | |
248 | use AnyEvent; |
258 | use AnyEvent; |
249 | use AnyEvent::Fork::Util; |
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250 | use AnyEvent::Util (); |
259 | use AnyEvent::Util (); |
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260 | |
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261 | use IO::FDPass; |
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262 | |
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263 | our $VERSION = 0.2; |
251 | |
264 | |
252 | our $PERL; # the path to the perl interpreter, deduces with various forms of magic |
265 | our $PERL; # the path to the perl interpreter, deduces with various forms of magic |
253 | |
266 | |
254 | =item my $pool = new AnyEvent::Fork key => value... |
267 | =item my $pool = new AnyEvent::Fork key => value... |
255 | |
268 | |
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268 | our $TEMPLATE; |
281 | our $TEMPLATE; |
269 | |
282 | |
270 | sub _cmd { |
283 | sub _cmd { |
271 | my $self = shift; |
284 | my $self = shift; |
272 | |
285 | |
273 | #TODO: maybe append the packet to any existing string command already in the queue |
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274 | |
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275 | # ideally, we would want to use "a (w/a)*" as format string, but perl versions |
286 | # ideally, we would want to use "a (w/a)*" as format string, but perl |
276 | # from at least 5.8.9 to 5.16.3 are all buggy and can't unpack it. |
287 | # versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack |
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288 | # it. |
277 | push @{ $self->[2] }, pack "N/a", pack "(w/a)*", @_; |
289 | push @{ $self->[2] }, pack "L/a*", pack "(w/a*)*", @_; |
278 | |
290 | |
279 | $self->[3] ||= AE::io $self->[1], 1, sub { |
291 | unless ($self->[3]) { |
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292 | my $wcb = sub { |
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293 | do { |
280 | # send the next "thing" in the queue - either a reference to an fh, |
294 | # send the next "thing" in the queue - either a reference to an fh, |
281 | # or a plain string. |
295 | # or a plain string. |
282 | |
296 | |
283 | if (ref $self->[2][0]) { |
297 | if (ref $self->[2][0]) { |
284 | # send fh |
298 | # send fh |
285 | AnyEvent::Fork::Util::fd_send fileno $self->[1], fileno ${ $self->[2][0] } |
299 | unless (IO::FDPass::send fileno $self->[1], fileno ${ $self->[2][0] }) { |
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300 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
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301 | undef $self->[3]; |
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302 | die "AnyEvent::Fork: file descriptor send failure: $!"; |
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303 | } |
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304 | |
286 | and shift @{ $self->[2] }; |
305 | shift @{ $self->[2] }; |
287 | |
306 | |
288 | } else { |
307 | } else { |
289 | # send string |
308 | # send string |
290 | my $len = syswrite $self->[1], $self->[2][0] |
309 | my $len = syswrite $self->[1], $self->[2][0]; |
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310 | |
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311 | unless ($len) { |
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312 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
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313 | undef $self->[3]; |
291 | or do { undef $self->[3]; die "AnyEvent::Fork: command write failure: $!" }; |
314 | die "AnyEvent::Fork: command write failure: $!"; |
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315 | } |
292 | |
316 | |
293 | substr $self->[2][0], 0, $len, ""; |
317 | substr $self->[2][0], 0, $len, ""; |
294 | shift @{ $self->[2] } unless length $self->[2][0]; |
318 | shift @{ $self->[2] } unless length $self->[2][0]; |
295 | } |
319 | } |
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320 | } while @{ $self->[2] }; |
296 | |
321 | |
297 | unless (@{ $self->[2] }) { |
322 | # everything written |
298 | undef $self->[3]; |
323 | undef $self->[3]; |
299 | # invoke run callback |
324 | # invoke run callback |
300 | $self->[0]->($self->[1]) if $self->[0]; |
325 | $self->[0]->($self->[1]) if $self->[0]; |
301 | } |
326 | }; |
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327 | |
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328 | $wcb->(); |
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329 | |
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330 | $self->[3] ||= AE::io $self->[1], 1, $wcb |
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331 | if @{ $self->[2] }; |
302 | }; |
332 | } |
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333 | |
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334 | () # make sure we don't leak the watcher |
303 | } |
335 | } |
304 | |
336 | |
305 | sub _new { |
337 | sub _new { |
306 | my ($self, $fh) = @_; |
338 | my ($self, $fh) = @_; |
307 | |
339 | |
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327 | if ($pid eq 0) { |
359 | if ($pid eq 0) { |
328 | require AnyEvent::Fork::Serve; |
360 | require AnyEvent::Fork::Serve; |
329 | $AnyEvent::Fork::Serve::OWNER = $parent; |
361 | $AnyEvent::Fork::Serve::OWNER = $parent; |
330 | close $fh; |
362 | close $fh; |
331 | $0 = "$_[1] of $parent"; |
363 | $0 = "$_[1] of $parent"; |
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364 | $SIG{CHLD} = 'IGNORE'; |
332 | AnyEvent::Fork::Serve::serve ($slave); |
365 | AnyEvent::Fork::Serve::serve ($slave); |
333 | AnyEvent::Fork::Util::_exit 0; |
366 | exit 0; |
334 | } elsif (!$pid) { |
367 | } elsif (!$pid) { |
335 | die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
368 | die "AnyEvent::Fork::Early/Template: unable to fork template process: $!"; |
336 | } |
369 | } |
337 | |
370 | |
338 | AnyEvent::Fork->_new ($fh) |
371 | AnyEvent::Fork->_new ($fh) |
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394 | reduces the amount of memory sharing that is possible, and is also slower. |
427 | reduces the amount of memory sharing that is possible, and is also slower. |
395 | |
428 | |
396 | You should use C<new> whenever possible, except when having a template |
429 | You should use C<new> whenever possible, except when having a template |
397 | process around is unacceptable. |
430 | process around is unacceptable. |
398 | |
431 | |
399 | The path to the perl interpreter is divined usign various methods - first |
432 | The path to the perl interpreter is divined using various methods - first |
400 | C<$^X> is investigated to see if the path ends with something that sounds |
433 | C<$^X> is investigated to see if the path ends with something that sounds |
401 | as if it were the perl interpreter. Failing this, the module falls back to |
434 | as if it were the perl interpreter. Failing this, the module falls back to |
402 | using C<$Config::Config{perlpath}>. |
435 | using C<$Config::Config{perlpath}>. |
403 | |
436 | |
404 | =cut |
437 | =cut |
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413 | my $perl = $; |
446 | my $perl = $; |
414 | |
447 | |
415 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
448 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
416 | # that looks like perl. this obviously only works for posix and win32 |
449 | # that looks like perl. this obviously only works for posix and win32 |
417 | unless ( |
450 | unless ( |
418 | (AnyEvent::Fork::Util::WIN32 || $perl =~ m%^/%) |
451 | ($^O eq "MSWin32" || $perl =~ m%^/%) |
419 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
452 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
420 | ) { |
453 | ) { |
421 | # if it doesn't look perlish enough, try Config |
454 | # if it doesn't look perlish enough, try Config |
422 | require Config; |
455 | require Config; |
423 | $perl = $Config::Config{perlpath}; |
456 | $perl = $Config::Config{perlpath}; |
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434 | Proc::FastSpawn::fd_inherit (fileno $fh, 0); |
467 | Proc::FastSpawn::fd_inherit (fileno $fh, 0); |
435 | |
468 | |
436 | # quick. also doesn't work in win32. of course. what did you expect |
469 | # quick. also doesn't work in win32. of course. what did you expect |
437 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
470 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
438 | my %env = %ENV; |
471 | my %env = %ENV; |
439 | $env{PERL5LIB} = join +(AnyEvent::Fork::Util::WIN32 ? ";" : ":"), grep !ref, @INC; |
472 | $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
440 | |
473 | |
441 | Proc::FastSpawn::spawn ( |
474 | Proc::FastSpawn::spawn ( |
442 | $perl, |
475 | $perl, |
443 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
476 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
444 | [map "$_=$env{$_}", keys %env], |
477 | [map "$_=$env{$_}", keys %env], |
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499 | accomplished by simply not storing the file handles anywhere after passing |
532 | accomplished by simply not storing the file handles anywhere after passing |
500 | them to this method. |
533 | them to this method. |
501 | |
534 | |
502 | Returns the process object for easy chaining of method calls. |
535 | Returns the process object for easy chaining of method calls. |
503 | |
536 | |
504 | Example: pass an fh to a process, and release it without closing. it will |
537 | Example: pass a file handle to a process, and release it without |
505 | be closed automatically when it is no longer used. |
538 | closing. It will be closed automatically when it is no longer used. |
506 | |
539 | |
507 | $proc->send_fh ($my_fh); |
540 | $proc->send_fh ($my_fh); |
508 | undef $my_fh; # free the reference if you want, but DO NOT CLOSE IT |
541 | undef $my_fh; # free the reference if you want, but DO NOT CLOSE IT |
509 | |
542 | |
510 | =cut |
543 | =cut |
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523 | =item $proc = $proc->send_arg ($string, ...) |
556 | =item $proc = $proc->send_arg ($string, ...) |
524 | |
557 | |
525 | Send one or more argument strings to the process, to prepare a call to |
558 | Send one or more argument strings to the process, to prepare a call to |
526 | C<run>. The strings can be any octet string. |
559 | C<run>. The strings can be any octet string. |
527 | |
560 | |
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561 | The protocol is optimised to pass a moderate number of relatively short |
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562 | strings - while you can pass up to 4GB of data in one go, this is more |
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563 | meant to pass some ID information or other startup info, not big chunks of |
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564 | data. |
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565 | |
528 | Returns the process object for easy chaining of emthod calls. |
566 | Returns the process object for easy chaining of method calls. |
529 | |
567 | |
530 | =cut |
568 | =cut |
531 | |
569 | |
532 | sub send_arg { |
570 | sub send_arg { |
533 | my ($self, @arg) = @_; |
571 | my ($self, @arg) = @_; |
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554 | If the communication socket isn't used, it should be closed on both sides, |
592 | If the communication socket isn't used, it should be closed on both sides, |
555 | to save on kernel memory. |
593 | to save on kernel memory. |
556 | |
594 | |
557 | The socket is non-blocking in the parent, and blocking in the newly |
595 | The socket is non-blocking in the parent, and blocking in the newly |
558 | created process. The close-on-exec flag is set on both. Even if not used |
596 | created process. The close-on-exec flag is set on both. Even if not used |
559 | otherwise, the socket can be a good indicator for the existance of the |
597 | otherwise, the socket can be a good indicator for the existence of the |
560 | process - if the other process exits, you get a readable event on it, |
598 | process - if the other process exits, you get a readable event on it, |
561 | because exiting the process closes the socket (if it didn't create any |
599 | because exiting the process closes the socket (if it didn't create any |
562 | children using fork). |
600 | children using fork). |
563 | |
601 | |
564 | Example: create a template for a process pool, pass a few strings, some |
602 | Example: create a template for a process pool, pass a few strings, some |
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601 | $self->_cmd (r => $func); |
639 | $self->_cmd (r => $func); |
602 | } |
640 | } |
603 | |
641 | |
604 | =back |
642 | =back |
605 | |
643 | |
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644 | =head1 PERFORMANCE |
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645 | |
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646 | Now for some unscientific benchmark numbers (all done on an amd64 |
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647 | GNU/Linux box). These are intended to give you an idea of the relative |
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648 | performance you can expect, they are not meant to be absolute performance |
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649 | numbers. |
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650 | |
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651 | OK, so, I ran a simple benchmark that creates a socket pair, forks, calls |
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652 | exit in the child and waits for the socket to close in the parent. I did |
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653 | load AnyEvent, EV and AnyEvent::Fork, for a total process size of 5100kB. |
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654 | |
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655 | 2079 new processes per second, using manual socketpair + fork |
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656 | |
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657 | Then I did the same thing, but instead of calling fork, I called |
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658 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
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659 | socket form the child to close on exit. This does the same thing as manual |
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660 | socket pair + fork, except that what is forked is the template process |
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661 | (2440kB), and the socket needs to be passed to the server at the other end |
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662 | of the socket first. |
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663 | |
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664 | 2307 new processes per second, using AnyEvent::Fork->new |
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665 | |
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666 | And finally, using C<new_exec> instead C<new>, using vforks+execs to exec |
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667 | a new perl interpreter and compile the small server each time, I get: |
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668 | |
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669 | 479 vfork+execs per second, using AnyEvent::Fork->new_exec |
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670 | |
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671 | So how can C<< AnyEvent->new >> be faster than a standard fork, even |
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672 | though it uses the same operations, but adds a lot of overhead? |
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673 | |
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674 | The difference is simply the process size: forking the 6MB process takes |
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675 | so much longer than forking the 2.5MB template process that the overhead |
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676 | introduced is canceled out. |
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677 | |
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678 | If the benchmark process grows, the normal fork becomes even slower: |
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679 | |
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680 | 1340 new processes, manual fork in a 20MB process |
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681 | 731 new processes, manual fork in a 200MB process |
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682 | 235 new processes, manual fork in a 2000MB process |
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683 | |
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684 | What that means (to me) is that I can use this module without having a |
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685 | very bad conscience because of the extra overhead required to start new |
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686 | processes. |
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687 | |
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688 | =head1 TYPICAL PROBLEMS |
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689 | |
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690 | This section lists typical problems that remain. I hope by recognising |
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691 | them, most can be avoided. |
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692 | |
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693 | =over 4 |
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694 | |
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695 | =item exit runs destructors |
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696 | |
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697 | =item "leaked" file descriptors for exec'ed processes |
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698 | |
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699 | POSIX systems inherit file descriptors by default when exec'ing a new |
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700 | process. While perl itself laudably sets the close-on-exec flags on new |
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701 | file handles, most C libraries don't care, and even if all cared, it's |
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702 | often not possible to set the flag in a race-free manner. |
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703 | |
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704 | That means some file descriptors can leak through. And since it isn't |
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705 | possible to know which file descriptors are "good" and "necessary" (or |
|
|
706 | even to know which file descriptors are open), there is no good way to |
|
|
707 | close the ones that might harm. |
|
|
708 | |
|
|
709 | As an example of what "harm" can be done consider a web server that |
|
|
710 | accepts connections and afterwards some module uses AnyEvent::Fork for the |
|
|
711 | first time, causing it to fork and exec a new process, which might inherit |
|
|
712 | the network socket. When the server closes the socket, it is still open |
|
|
713 | in the child (which doesn't even know that) and the client might conclude |
|
|
714 | that the connection is still fine. |
|
|
715 | |
|
|
716 | For the main program, there are multiple remedies available - |
|
|
717 | L<AnyEvent::Fork::Early> is one, creating a process early and not using |
|
|
718 | C<new_exec> is another, as in both cases, the first process can be exec'ed |
|
|
719 | well before many random file descriptors are open. |
|
|
720 | |
|
|
721 | In general, the solution for these kind of problems is to fix the |
|
|
722 | libraries or the code that leaks those file descriptors. |
|
|
723 | |
|
|
724 | Fortunately, most of these leaked descriptors do no harm, other than |
|
|
725 | sitting on some resources. |
|
|
726 | |
|
|
727 | =item "leaked" file descriptors for fork'ed processes |
|
|
728 | |
|
|
729 | Normally, L<AnyEvent::Fork> does start new processes by exec'ing them, |
|
|
730 | which closes file descriptors not marked for being inherited. |
|
|
731 | |
|
|
732 | However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer |
|
|
733 | a way to create these processes by forking, and this leaks more file |
|
|
734 | descriptors than exec'ing them, as there is no way to mark descriptors as |
|
|
735 | "close on fork". |
|
|
736 | |
|
|
737 | An example would be modules like L<EV>, L<IO::AIO> or L<Gtk2>. Both create |
|
|
738 | pipes for internal uses, and L<Gtk2> might open a connection to the X |
|
|
739 | server. L<EV> and L<IO::AIO> can deal with fork, but Gtk2 might have |
|
|
740 | trouble with a fork. |
|
|
741 | |
|
|
742 | The solution is to either not load these modules before use'ing |
|
|
743 | L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template>, or to delay |
|
|
744 | initialising them, for example, by calling C<init Gtk2> manually. |
|
|
745 | |
|
|
746 | =back |
|
|
747 | |
606 | =head1 PORTABILITY NOTES |
748 | =head1 PORTABILITY NOTES |
607 | |
749 | |
608 | Native win32 perls are somewhat supported (AnyEvent::Fork::Early is a nop, |
750 | Native win32 perls are somewhat supported (AnyEvent::Fork::Early is a nop, |
609 | and ::Template is not going to work), and it cost a lot of blood and sweat |
751 | and ::Template is not going to work), and it cost a lot of blood and sweat |
610 | to make it so, mostly due to the bloody broken perl that nobody seems to |
752 | to make it so, mostly due to the bloody broken perl that nobody seems to |
611 | care about. The fork emulation is a bad joke - I have yet to see something |
753 | care about. The fork emulation is a bad joke - I have yet to see something |
612 | useful that you cna do with it without running into memory corruption |
754 | useful that you can do with it without running into memory corruption |
613 | issues or other braindamage. Hrrrr. |
755 | issues or other braindamage. Hrrrr. |
614 | |
756 | |
615 | Cygwin perl is not supported at the moment, as it should implement fd |
757 | Cygwin perl is not supported at the moment, as it should implement fd |
616 | passing, but doesn't, and rolling my own is hard, as cygwin doesn't |
758 | passing, but doesn't, and rolling my own is hard, as cygwin doesn't |
617 | support enough functionality to do it. |
759 | support enough functionality to do it. |
618 | |
760 | |
|
|
761 | =head1 SEE ALSO |
|
|
762 | |
|
|
763 | L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), |
|
|
764 | L<AnyEvent::Fork::Template> (to create a process by forking the main |
|
|
765 | program at a convenient time). |
|
|
766 | |
619 | =head1 AUTHOR |
767 | =head1 AUTHOR |
620 | |
768 | |
621 | Marc Lehmann <schmorp@schmorp.de> |
769 | Marc Lehmann <schmorp@schmorp.de> |
622 | http://home.schmorp.de/ |
770 | http://home.schmorp.de/ |
623 | |
771 | |