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Revision 1.128 by root, Wed Sep 19 21:39:15 2007 UTC vs.
Revision 1.179 by root, Sat Apr 19 19:06:02 2008 UTC

2 2
3Coro - coroutine process abstraction 3Coro - coroutine process abstraction
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use Coro; 7 use Coro;
8 8
9 async { 9 async {
10 # some asynchronous thread of execution 10 # some asynchronous thread of execution
11 print "2\n";
12 cede; # yield back to main
13 print "4\n";
11 }; 14 };
12 15 print "1\n";
13 # alternatively create an async coroutine like this: 16 cede; # yield to coroutine
14 17 print "3\n";
15 sub some_func : Coro { 18 cede; # and again
16 # some more async code 19
17 } 20 # use locking
18 21 my $lock = new Coro::Semaphore;
19 cede; 22 my $locked;
23
24 $lock->down;
25 $locked = 1;
26 $lock->up;
20 27
21=head1 DESCRIPTION 28=head1 DESCRIPTION
22 29
23This module collection manages coroutines. Coroutines are similar 30This module collection manages coroutines. Coroutines are similar
24to threads but don't run in parallel at the same time even on SMP 31to threads but don't run in parallel at the same time even on SMP
33is a performance win on Windows machines, and a loss everywhere else). 40is a performance win on Windows machines, and a loss everywhere else).
34 41
35In this module, coroutines are defined as "callchain + lexical variables + 42In this module, coroutines are defined as "callchain + lexical variables +
36@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, 43@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
37its own set of lexicals and its own set of perls most important global 44its own set of lexicals and its own set of perls most important global
38variables. 45variables (see L<Coro::State> for more configuration).
39 46
40=cut 47=cut
41 48
42package Coro; 49package Coro;
43 50
50 57
51our $idle; # idle handler 58our $idle; # idle handler
52our $main; # main coroutine 59our $main; # main coroutine
53our $current; # current coroutine 60our $current; # current coroutine
54 61
55our $VERSION = '3.7'; 62our $VERSION = '4.51';
56 63
57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 64our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 65our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 66 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 67);
61our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); 68our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62 69
63{
64 my @async;
65 my $init;
66
67 # this way of handling attributes simply is NOT scalable ;()
68 sub import {
69 no strict 'refs';
70
71 Coro->export_to_level (1, @_);
72
73 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
74 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
75 my ($package, $ref) = (shift, shift);
76 my @attrs;
77 for (@_) {
78 if ($_ eq "Coro") {
79 push @async, $ref;
80 unless ($init++) {
81 eval q{
82 sub INIT {
83 &async(pop @async) while @async;
84 }
85 };
86 }
87 } else {
88 push @attrs, $_;
89 }
90 }
91 return $old ? $old->($package, $ref, @attrs) : @attrs;
92 };
93 }
94
95}
96
97=over 4 70=over 4
98 71
99=item $main 72=item $main
100 73
101This coroutine represents the main program. 74This coroutine represents the main program.
113reasons. If performance is not essential you are encouraged to use the 86reasons. If performance is not essential you are encouraged to use the
114C<Coro::current> function instead. 87C<Coro::current> function instead.
115 88
116=cut 89=cut
117 90
91$main->{desc} = "[main::]";
92
118# maybe some other module used Coro::Specific before... 93# maybe some other module used Coro::Specific before...
119$main->{specific} = $current->{specific} 94$main->{_specific} = $current->{_specific}
120 if $current; 95 if $current;
121 96
122_set_current $main; 97_set_current $main;
123 98
124sub current() { $current } 99sub current() { $current }
132This hook is overwritten by modules such as C<Coro::Timer> and 107This hook is overwritten by modules such as C<Coro::Timer> and
133C<Coro::Event> to wait on an external event that hopefully wake up a 108C<Coro::Event> to wait on an external event that hopefully wake up a
134coroutine so the scheduler can run it. 109coroutine so the scheduler can run it.
135 110
136Please note that if your callback recursively invokes perl (e.g. for event 111Please note that if your callback recursively invokes perl (e.g. for event
137handlers), then it must be prepared to be called recursively. 112handlers), then it must be prepared to be called recursively itself.
138 113
139=cut 114=cut
140 115
141$idle = sub { 116$idle = sub {
142 require Carp; 117 require Carp;
149 # free coroutine data and mark as destructed 124 # free coroutine data and mark as destructed
150 $self->_destroy 125 $self->_destroy
151 or return; 126 or return;
152 127
153 # call all destruction callbacks 128 # call all destruction callbacks
154 $_->(@{$self->{status}}) 129 $_->(@{$self->{_status}})
155 for @{(delete $self->{destroy_cb}) || []}; 130 for @{(delete $self->{_on_destroy}) || []};
156} 131}
157 132
158# this coroutine is necessary because a coroutine 133# this coroutine is necessary because a coroutine
159# cannot destroy itself. 134# cannot destroy itself.
160my @destroy; 135my @destroy;
166 while @destroy; 141 while @destroy;
167 142
168 &schedule; 143 &schedule;
169 } 144 }
170}; 145};
171 146$manager->desc ("[coro manager]");
172$manager->prio (PRIO_MAX); 147$manager->prio (PRIO_MAX);
173
174# static methods. not really.
175 148
176=back 149=back
177 150
178=head2 STATIC METHODS 151=head2 STATIC METHODS
179 152
184=item async { ... } [@args...] 157=item async { ... } [@args...]
185 158
186Create a new asynchronous coroutine and return it's coroutine object 159Create a new asynchronous coroutine and return it's coroutine object
187(usually unused). When the sub returns the new coroutine is automatically 160(usually unused). When the sub returns the new coroutine is automatically
188terminated. 161terminated.
162
163See the C<Coro::State::new> constructor for info about the coroutine
164environment in which coroutines run.
189 165
190Calling C<exit> in a coroutine will do the same as calling exit outside 166Calling C<exit> in a coroutine will do the same as calling exit outside
191the coroutine. Likewise, when the coroutine dies, the program will exit, 167the coroutine. Likewise, when the coroutine dies, the program will exit,
192just as it would in the main program. 168just as it would in the main program.
193 169
214issued in case of an exception instead of terminating the program, as 190issued in case of an exception instead of terminating the program, as
215C<async> does. As the coroutine is being reused, stuff like C<on_destroy> 191C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
216will not work in the expected way, unless you call terminate or cancel, 192will not work in the expected way, unless you call terminate or cancel,
217which somehow defeats the purpose of pooling. 193which somehow defeats the purpose of pooling.
218 194
219The priority will be reset to C<0> after each job, otherwise the coroutine 195The priority will be reset to C<0> after each job, tracing will be
220will be re-used "as-is". 196disabled, the description will be reset and the default output filehandle
197gets restored, so you can change alkl these. Otherwise the coroutine will
198be re-used "as-is": most notably if you change other per-coroutine global
199stuff such as C<$/> you need to revert that change, which is most simply
200done by using local as in C< local $/ >.
221 201
222The pool size is limited to 8 idle coroutines (this can be adjusted by 202The pool size is limited to 8 idle coroutines (this can be adjusted by
223changing $Coro::POOL_SIZE), and there can be as many non-idle coros as 203changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
224required. 204required.
225 205
226If you are concerned about pooled coroutines growing a lot because a 206If you are concerned about pooled coroutines growing a lot because a
227single C<async_pool> used a lot of stackspace you can e.g. C<async_pool { 207single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
228terminate }> once per second or so to slowly replenish the pool. 208{ terminate }> once per second or so to slowly replenish the pool. In
209addition to that, when the stacks used by a handler grows larger than 16kb
210(adjustable with $Coro::POOL_RSS) it will also exit.
229 211
230=cut 212=cut
231 213
232our $POOL_SIZE = 8; 214our $POOL_SIZE = 8;
215our $POOL_RSS = 16 * 1024;
233our @pool; 216our @async_pool;
234 217
235sub pool_handler { 218sub pool_handler {
219 my $cb;
220
236 while () { 221 while () {
237 eval { 222 eval {
238 my ($cb, @arg) = @{ delete $current->{_invoke} or return }; 223 while () {
239 $cb->(@arg); 224 _pool_1 $cb;
225 &$cb;
226 _pool_2 $cb;
227 &schedule;
228 }
240 }; 229 };
230
231 last if $@ eq "\3async_pool terminate\2\n";
241 warn $@ if $@; 232 warn $@ if $@;
242
243 last if @pool >= $POOL_SIZE;
244 push @pool, $current;
245
246 $current->save (Coro::State::SAVE_DEF);
247 $current->prio (0);
248 schedule;
249 } 233 }
250} 234}
251 235
252sub async_pool(&@) { 236sub async_pool(&@) {
253 # this is also inlined into the unlock_scheduler 237 # this is also inlined into the unlock_scheduler
254 my $coro = (pop @pool) || do {
255 my $coro = new Coro \&pool_handler; 238 my $coro = (pop @async_pool) || new Coro \&pool_handler;
256 $coro->{desc} = "async_pool";
257 $coro
258 };
259 239
260 $coro->{_invoke} = [@_]; 240 $coro->{_invoke} = [@_];
261 $coro->ready; 241 $coro->ready;
262 242
263 $coro 243 $coro
293 273
294"Cede" to other coroutines. This function puts the current coroutine into the 274"Cede" to other coroutines. This function puts the current coroutine into the
295ready queue and calls C<schedule>, which has the effect of giving up the 275ready queue and calls C<schedule>, which has the effect of giving up the
296current "timeslice" to other coroutines of the same or higher priority. 276current "timeslice" to other coroutines of the same or higher priority.
297 277
298Returns true if at least one coroutine switch has happened.
299
300=item Coro::cede_notself 278=item Coro::cede_notself
301 279
302Works like cede, but is not exported by default and will cede to any 280Works like cede, but is not exported by default and will cede to any
303coroutine, regardless of priority, once. 281coroutine, regardless of priority, once.
304 282
305Returns true if at least one coroutine switch has happened.
306
307=item terminate [arg...] 283=item terminate [arg...]
308 284
309Terminates the current coroutine with the given status values (see L<cancel>). 285Terminates the current coroutine with the given status values (see L<cancel>).
286
287=item killall
288
289Kills/terminates/cancels all coroutines except the currently running
290one. This is useful after a fork, either in the child or the parent, as
291usually only one of them should inherit the running coroutines.
310 292
311=cut 293=cut
312 294
313sub terminate { 295sub terminate {
314 $current->cancel (@_); 296 $current->cancel (@_);
315} 297}
316 298
299sub killall {
300 for (Coro::State::list) {
301 $_->cancel
302 if $_ != $current && UNIVERSAL::isa $_, "Coro";
303 }
304}
305
317=back 306=back
318
319# dynamic methods
320 307
321=head2 COROUTINE METHODS 308=head2 COROUTINE METHODS
322 309
323These are the methods you can call on coroutine objects. 310These are the methods you can call on coroutine objects.
324 311
329Create a new coroutine and return it. When the sub returns the coroutine 316Create a new coroutine and return it. When the sub returns the coroutine
330automatically terminates as if C<terminate> with the returned values were 317automatically terminates as if C<terminate> with the returned values were
331called. To make the coroutine run you must first put it into the ready queue 318called. To make the coroutine run you must first put it into the ready queue
332by calling the ready method. 319by calling the ready method.
333 320
334See C<async> for additional discussion. 321See C<async> and C<Coro::State::new> for additional info about the
322coroutine environment.
335 323
336=cut 324=cut
337 325
338sub _run_coro { 326sub _run_coro {
339 terminate &{+shift}; 327 terminate &{+shift};
363 351
364=cut 352=cut
365 353
366sub cancel { 354sub cancel {
367 my $self = shift; 355 my $self = shift;
368 $self->{status} = [@_]; 356 $self->{_status} = [@_];
369 357
370 if ($current == $self) { 358 if ($current == $self) {
371 push @destroy, $self; 359 push @destroy, $self;
372 $manager->ready; 360 $manager->ready;
373 &schedule while 1; 361 &schedule while 1;
377} 365}
378 366
379=item $coroutine->join 367=item $coroutine->join
380 368
381Wait until the coroutine terminates and return any values given to the 369Wait until the coroutine terminates and return any values given to the
382C<terminate> or C<cancel> functions. C<join> can be called multiple times 370C<terminate> or C<cancel> functions. C<join> can be called concurrently
383from multiple coroutine. 371from multiple coroutines.
384 372
385=cut 373=cut
386 374
387sub join { 375sub join {
388 my $self = shift; 376 my $self = shift;
389 377
390 unless ($self->{status}) { 378 unless ($self->{_status}) {
391 my $current = $current; 379 my $current = $current;
392 380
393 push @{$self->{destroy_cb}}, sub { 381 push @{$self->{_on_destroy}}, sub {
394 $current->ready; 382 $current->ready;
395 undef $current; 383 undef $current;
396 }; 384 };
397 385
398 &schedule while $current; 386 &schedule while $current;
399 } 387 }
400 388
401 wantarray ? @{$self->{status}} : $self->{status}[0]; 389 wantarray ? @{$self->{_status}} : $self->{_status}[0];
402} 390}
403 391
404=item $coroutine->on_destroy (\&cb) 392=item $coroutine->on_destroy (\&cb)
405 393
406Registers a callback that is called when this coroutine gets destroyed, 394Registers a callback that is called when this coroutine gets destroyed,
410=cut 398=cut
411 399
412sub on_destroy { 400sub on_destroy {
413 my ($self, $cb) = @_; 401 my ($self, $cb) = @_;
414 402
415 push @{ $self->{destroy_cb} }, $cb; 403 push @{ $self->{_on_destroy} }, $cb;
416} 404}
417 405
418=item $oldprio = $coroutine->prio ($newprio) 406=item $oldprio = $coroutine->prio ($newprio)
419 407
420Sets (or gets, if the argument is missing) the priority of the 408Sets (or gets, if the argument is missing) the priority of the
444 432
445=item $olddesc = $coroutine->desc ($newdesc) 433=item $olddesc = $coroutine->desc ($newdesc)
446 434
447Sets (or gets in case the argument is missing) the description for this 435Sets (or gets in case the argument is missing) the description for this
448coroutine. This is just a free-form string you can associate with a coroutine. 436coroutine. This is just a free-form string you can associate with a coroutine.
437
438This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
439can modify this member directly if you wish.
440
441=item $coroutine->throw ([$scalar])
442
443If C<$throw> is specified and defined, it will be thrown as an exception
444inside the coroutine at the next convinient point in time (usually after
445it gains control at the next schedule/transfer/cede). Otherwise clears the
446exception object.
447
448The exception object will be thrown "as is" with the specified scalar in
449C<$@>, i.e. if it is a string, no line number or newline will be appended
450(unlike with C<die>).
451
452This can be used as a softer means than C<cancel> to ask a coroutine to
453end itself, although there is no guarentee that the exception will lead to
454termination, and if the exception isn't caught it might well end the whole
455program.
449 456
450=cut 457=cut
451 458
452sub desc { 459sub desc {
453 my $old = $_[0]{desc}; 460 my $old = $_[0]{desc};
529 536
530# we create a special coro because we want to cede, 537# we create a special coro because we want to cede,
531# to reduce pressure on the coro pool (because most callbacks 538# to reduce pressure on the coro pool (because most callbacks
532# return immediately and can be reused) and because we cannot cede 539# return immediately and can be reused) and because we cannot cede
533# inside an event callback. 540# inside an event callback.
534our $unblock_scheduler = async { 541our $unblock_scheduler = new Coro sub {
535 while () { 542 while () {
536 while (my $cb = pop @unblock_queue) { 543 while (my $cb = pop @unblock_queue) {
537 # this is an inlined copy of async_pool 544 # this is an inlined copy of async_pool
538 my $coro = (pop @pool or new Coro \&pool_handler); 545 my $coro = (pop @async_pool) || new Coro \&pool_handler;
539 546
540 $coro->{_invoke} = $cb; 547 $coro->{_invoke} = $cb;
541 $coro->ready; 548 $coro->ready;
542 cede; # for short-lived callbacks, this reduces pressure on the coro pool 549 cede; # for short-lived callbacks, this reduces pressure on the coro pool
543 } 550 }
544 schedule; # sleep well 551 schedule; # sleep well
545 } 552 }
546}; 553};
554$unblock_scheduler->desc ("[unblock_sub scheduler]");
547 555
548sub unblock_sub(&) { 556sub unblock_sub(&) {
549 my $cb = shift; 557 my $cb = shift;
550 558
551 sub { 559 sub {
570 to allow per-thread schedulers, but Coro::State does not yet allow 578 to allow per-thread schedulers, but Coro::State does not yet allow
571 this). 579 this).
572 580
573=head1 SEE ALSO 581=head1 SEE ALSO
574 582
583Lower level Configuration, Coroutine Environment: L<Coro::State>.
584
585Debugging: L<Coro::Debug>.
586
575Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. 587Support/Utility: L<Coro::Specific>, L<Coro::Util>.
576 588
577Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. 589Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
578 590
579Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. 591Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>.
580 592
593Compatibility: L<Coro::LWP>, L<Coro::Storable>, L<Coro::Select>.
594
581Embedding: L<Coro:MakeMaker> 595Embedding: L<Coro::MakeMaker>.
582 596
583=head1 AUTHOR 597=head1 AUTHOR
584 598
585 Marc Lehmann <schmorp@schmorp.de> 599 Marc Lehmann <schmorp@schmorp.de>
586 http://home.schmorp.de/ 600 http://home.schmorp.de/

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