… | |
… | |
40 | points in your program, so locking and parallel access are rarely an |
40 | points in your program, so locking and parallel access are rarely an |
41 | issue, making thread programming much safer and easier than using other |
41 | issue, making thread programming much safer and easier than using other |
42 | thread models. |
42 | thread models. |
43 | |
43 | |
44 | Unlike the so-called "Perl threads" (which are not actually real threads |
44 | Unlike the so-called "Perl threads" (which are not actually real threads |
45 | but only the windows process emulation (see section of same name for more |
45 | but only the windows process emulation (see section of same name for |
46 | details) ported to unix, and as such act as processes), Coro provides |
46 | more details) ported to UNIX, and as such act as processes), Coro |
47 | a full shared address space, which makes communication between threads |
47 | provides a full shared address space, which makes communication between |
48 | very easy. And Coro's threads are fast, too: disabling the Windows |
48 | threads very easy. And coro threads are fast, too: disabling the Windows |
49 | process emulation code in your perl and using Coro can easily result in |
49 | process emulation code in your perl and using Coro can easily result in |
50 | a two to four times speed increase for your programs. A parallel matrix |
50 | a two to four times speed increase for your programs. A parallel matrix |
51 | multiplication benchmark runs over 300 times faster on a single core than |
51 | multiplication benchmark (very communication-intensive) runs over 300 |
52 | perl's pseudo-threads on a quad core using all four cores. |
52 | times faster on a single core than perls pseudo-threads on a quad core |
|
|
53 | using all four cores. |
53 | |
54 | |
54 | Coro achieves that by supporting multiple running interpreters that share |
55 | Coro achieves that by supporting multiple running interpreters that share |
55 | data, which is especially useful to code pseudo-parallel processes and |
56 | data, which is especially useful to code pseudo-parallel processes and |
56 | for event-based programming, such as multiple HTTP-GET requests running |
57 | for event-based programming, such as multiple HTTP-GET requests running |
57 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
58 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
… | |
… | |
63 | variables (see L<Coro::State> for more configuration and background info). |
64 | variables (see L<Coro::State> for more configuration and background info). |
64 | |
65 | |
65 | See also the C<SEE ALSO> section at the end of this document - the Coro |
66 | See also the C<SEE ALSO> section at the end of this document - the Coro |
66 | module family is quite large. |
67 | module family is quite large. |
67 | |
68 | |
|
|
69 | =head1 CORO THREAD LIFE CYCLE |
|
|
70 | |
|
|
71 | During the long and exciting (or not) life of a coro thread, it goes |
|
|
72 | through a number of states: |
|
|
73 | |
|
|
74 | =over 4 |
|
|
75 | |
|
|
76 | =item 1. Creation |
|
|
77 | |
|
|
78 | The first thing in the life of a coro thread is it's creation - |
|
|
79 | obviously. The typical way to create a thread is to call the C<async |
|
|
80 | BLOCK> function: |
|
|
81 | |
|
|
82 | async { |
|
|
83 | # thread code goes here |
|
|
84 | }; |
|
|
85 | |
|
|
86 | You can also pass arguments, which are put in C<@_>: |
|
|
87 | |
|
|
88 | async { |
|
|
89 | print $_[1]; # prints 2 |
|
|
90 | } 1, 2, 3; |
|
|
91 | |
|
|
92 | This creates a new coro thread and puts it into the ready queue, meaning |
|
|
93 | it will run as soon as the CPU is free for it. |
|
|
94 | |
|
|
95 | C<async> will return a coro object - you can store this for future |
|
|
96 | reference or ignore it, the thread itself will keep a reference to it's |
|
|
97 | thread object - threads are alive on their own. |
|
|
98 | |
|
|
99 | Another way to create a thread is to call the C<new> constructor with a |
|
|
100 | code-reference: |
|
|
101 | |
|
|
102 | new Coro sub { |
|
|
103 | # thread code goes here |
|
|
104 | }, @optional_arguments; |
|
|
105 | |
|
|
106 | This is quite similar to calling C<async>, but the important difference is |
|
|
107 | that the new thread is not put into the ready queue, so the thread will |
|
|
108 | not run until somebody puts it there. C<async> is, therefore, identical to |
|
|
109 | this sequence: |
|
|
110 | |
|
|
111 | my $coro = new Coro sub { |
|
|
112 | # thread code goes here |
|
|
113 | }; |
|
|
114 | $coro->ready; |
|
|
115 | return $coro; |
|
|
116 | |
|
|
117 | =item 2. Startup |
|
|
118 | |
|
|
119 | When a new coro thread is created, only a copy of the code reference |
|
|
120 | and the arguments are stored, no extra memory for stacks and so on is |
|
|
121 | allocated, keeping the coro thread in a low-memory state. |
|
|
122 | |
|
|
123 | Only when it actually starts executing will all the resources be finally |
|
|
124 | allocated. |
|
|
125 | |
|
|
126 | The optional arguments specified at coro creation are available in C<@_>, |
|
|
127 | similar to function calls. |
|
|
128 | |
|
|
129 | =item 3. Running / Blocking |
|
|
130 | |
|
|
131 | A lot can happen after the coro thread has started running. Quite usually, |
|
|
132 | it will not run to the end in one go (because you could use a function |
|
|
133 | instead), but it will give up the CPU regularly because it waits for |
|
|
134 | external events. |
|
|
135 | |
|
|
136 | As long as a coro thread runs, it's coro object is available in the global |
|
|
137 | variable C<$Coro::current>. |
|
|
138 | |
|
|
139 | The low-level way to give up the CPU is to call the scheduler, which |
|
|
140 | selects a new coro thread to run: |
|
|
141 | |
|
|
142 | Coro::schedule; |
|
|
143 | |
|
|
144 | Since running threads are not in the ready queue, calling the scheduler |
|
|
145 | without doing anything else will block the coro thread forever - you need |
|
|
146 | to arrange either for the coro to put woken up (readied) by some other |
|
|
147 | event or some other thread, or you can put it into the ready queue before |
|
|
148 | scheduling: |
|
|
149 | |
|
|
150 | # this is exactly what Coro::cede does |
|
|
151 | $Coro::current->ready; |
|
|
152 | Coro::schedule; |
|
|
153 | |
|
|
154 | All the higher-level synchronisation methods (Coro::Semaphore, |
|
|
155 | Coro::rouse_*...) are actually implemented via C<< ->ready >> and C<< |
|
|
156 | Coro::schedule >>. |
|
|
157 | |
|
|
158 | While the coro thread is running it also might get assigned a C-level |
|
|
159 | thread, or the C-level thread might be unassigned from it, as the Coro |
|
|
160 | runtime wishes. A C-level thread needs to be assigned when your perl |
|
|
161 | thread calls into some C-level function and that function in turn calls |
|
|
162 | perl and perl then wants to switch coroutines. This happens most often |
|
|
163 | when you run an event loop and block in the callback, or when perl |
|
|
164 | itself calls some function such as C<AUTOLOAD> or methods via the C<tie> |
|
|
165 | mechanism. |
|
|
166 | |
|
|
167 | =item 4. Termination |
|
|
168 | |
|
|
169 | Many threads actually terminate after some time. There are a number of |
|
|
170 | ways to terminate a coro thread, the simplest is returning from the |
|
|
171 | top-level code reference: |
|
|
172 | |
|
|
173 | async { |
|
|
174 | # after returning from here, the coro thread is terminated |
|
|
175 | }; |
|
|
176 | |
|
|
177 | async { |
|
|
178 | return if 0.5 < rand; # terminate a little earlier, maybe |
|
|
179 | print "got a chance to print this\n"; |
|
|
180 | # or here |
|
|
181 | }; |
|
|
182 | |
|
|
183 | Any values returned from the coroutine can be recovered using C<< ->join |
|
|
184 | >>: |
|
|
185 | |
|
|
186 | my $coro = async { |
|
|
187 | "hello, world\n" # return a string |
|
|
188 | }; |
|
|
189 | |
|
|
190 | my $hello_world = $coro->join; |
|
|
191 | |
|
|
192 | print $hello_world; |
|
|
193 | |
|
|
194 | Another way to terminate is to call C<< Coro::terminate >>, which at any |
|
|
195 | subroutine call nesting level: |
|
|
196 | |
|
|
197 | async { |
|
|
198 | Coro::terminate "return value 1", "return value 2"; |
|
|
199 | }; |
|
|
200 | |
|
|
201 | And yet another way is to C<< ->cancel >> (or C<< ->safe_cancel >>) the |
|
|
202 | coro thread from another thread: |
|
|
203 | |
|
|
204 | my $coro = async { |
|
|
205 | exit 1; |
|
|
206 | }; |
|
|
207 | |
|
|
208 | $coro->cancel; # also accepts values for ->join to retrieve |
|
|
209 | |
|
|
210 | Cancellation I<can> be dangerous - it's a bit like calling C<exit> without |
|
|
211 | actually exiting, and might leave C libraries and XS modules in a weird |
|
|
212 | state. Unlike other thread implementations, however, Coro is exceptionally |
|
|
213 | safe with regards to cancellation, as perl will always be in a consistent |
|
|
214 | state, and for those cases where you want to do truly marvellous things |
|
|
215 | with your coro while it is being cancelled - that is, make sure all |
|
|
216 | cleanup code is executed from the thread being cancelled - there is even a |
|
|
217 | C<< ->safe_cancel >> method. |
|
|
218 | |
|
|
219 | So, cancelling a thread that runs in an XS event loop might not be the |
|
|
220 | best idea, but any other combination that deals with perl only (cancelling |
|
|
221 | when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is |
|
|
222 | safe. |
|
|
223 | |
|
|
224 | =item 5. Cleanup |
|
|
225 | |
|
|
226 | Threads will allocate various resources. Most but not all will be returned |
|
|
227 | when a thread terminates, during clean-up. |
|
|
228 | |
|
|
229 | Cleanup is quite similar to throwing an uncaught exception: perl will |
|
|
230 | work it's way up through all subroutine calls and blocks. On it's way, it |
|
|
231 | will release all C<my> variables, undo all C<local>'s and free any other |
|
|
232 | resources truly local to the thread. |
|
|
233 | |
|
|
234 | So, a common way to free resources is to keep them referenced only by my |
|
|
235 | variables: |
|
|
236 | |
|
|
237 | async { |
|
|
238 | my $big_cache = new Cache ...; |
|
|
239 | }; |
|
|
240 | |
|
|
241 | If there are no other references, then the C<$big_cache> object will be |
|
|
242 | freed when the thread terminates, regardless of how it does so. |
|
|
243 | |
|
|
244 | What it does C<NOT> do is unlock any Coro::Semaphores or similar |
|
|
245 | resources, but that's where the C<guard> methods come in handy: |
|
|
246 | |
|
|
247 | my $sem = new Coro::Semaphore; |
|
|
248 | |
|
|
249 | async { |
|
|
250 | my $lock_guard = $sem->guard; |
|
|
251 | # if we reutrn, or die or get cancelled, here, |
|
|
252 | # then the semaphore will be "up"ed. |
|
|
253 | }; |
|
|
254 | |
|
|
255 | The C<Guard::guard> function comes in handy for any custom cleanup you |
|
|
256 | might want to do: |
|
|
257 | |
|
|
258 | async { |
|
|
259 | my $window = new Gtk2::Window "toplevel"; |
|
|
260 | # The window will not be cleaned up automatically, even when $window |
|
|
261 | # gets freed, so use a guard to ensure it's destruction |
|
|
262 | # in case of an error: |
|
|
263 | my $window_guard = Guard::guard { $window->destroy }; |
|
|
264 | |
|
|
265 | # we are safe here |
|
|
266 | }; |
|
|
267 | |
|
|
268 | Last not least, C<local> can often be handy, too, e.g. when temporarily |
|
|
269 | replacing the coro thread description: |
|
|
270 | |
|
|
271 | sub myfunction { |
|
|
272 | local $Coro::current->{desc} = "inside myfunction(@_)"; |
|
|
273 | |
|
|
274 | # if we return or die here, the description will be restored |
|
|
275 | } |
|
|
276 | |
|
|
277 | =item 6. Viva La Zombie Muerte |
|
|
278 | |
|
|
279 | Even after a thread has terminated and cleaned up it's resources, the coro |
|
|
280 | object still is there and stores the return values of the thread. Only in |
|
|
281 | this state will the coro object be "reference counted" in the normal perl |
|
|
282 | sense: the thread code keeps a reference to it when it is active, but not |
|
|
283 | after it has terminated. |
|
|
284 | |
|
|
285 | The means the coro object gets freed automatically when the thread has |
|
|
286 | terminated and cleaned up and there arenot other references. |
|
|
287 | |
|
|
288 | If there are, the coro object will stay around, and you can call C<< |
|
|
289 | ->join >> as many times as you wish to retrieve the result values: |
|
|
290 | |
|
|
291 | async { |
|
|
292 | print "hi\n"; |
|
|
293 | 1 |
|
|
294 | }; |
|
|
295 | |
|
|
296 | # run the async above, and free everything before returning |
|
|
297 | # from Coro::cede: |
|
|
298 | Coro::cede; |
|
|
299 | |
|
|
300 | { |
|
|
301 | my $coro = async { |
|
|
302 | print "hi\n"; |
|
|
303 | 1 |
|
|
304 | }; |
|
|
305 | |
|
|
306 | # run the async above, and clean up, but do not free the coro |
|
|
307 | # object: |
|
|
308 | Coro::cede; |
|
|
309 | |
|
|
310 | # optionally retrieve the result values |
|
|
311 | my @results = $coro->join; |
|
|
312 | |
|
|
313 | # now $coro goes out of scope, and presumably gets freed |
|
|
314 | }; |
|
|
315 | |
|
|
316 | =back |
|
|
317 | |
68 | =cut |
318 | =cut |
69 | |
319 | |
70 | package Coro; |
320 | package Coro; |
71 | |
321 | |
72 | use common::sense; |
322 | use common::sense; |
… | |
… | |
81 | |
331 | |
82 | our $idle; # idle handler |
332 | our $idle; # idle handler |
83 | our $main; # main coro |
333 | our $main; # main coro |
84 | our $current; # current coro |
334 | our $current; # current coro |
85 | |
335 | |
86 | our $VERSION = 5.21; |
336 | our $VERSION = 5.372; |
87 | |
337 | |
88 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
338 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
89 | our %EXPORT_TAGS = ( |
339 | our %EXPORT_TAGS = ( |
90 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
340 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
91 | ); |
341 | ); |
… | |
… | |
131 | |
381 | |
132 | The default implementation dies with "FATAL: deadlock detected.", followed |
382 | The default implementation dies with "FATAL: deadlock detected.", followed |
133 | by a thread listing, because the program has no other way to continue. |
383 | by a thread listing, because the program has no other way to continue. |
134 | |
384 | |
135 | This hook is overwritten by modules such as C<Coro::EV> and |
385 | This hook is overwritten by modules such as C<Coro::EV> and |
136 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
386 | C<Coro::AnyEvent> to wait on an external event that hopefully wakes up a |
137 | coro so the scheduler can run it. |
387 | coro so the scheduler can run it. |
138 | |
388 | |
139 | See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. |
389 | See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. |
140 | |
390 | |
141 | =cut |
391 | =cut |
… | |
… | |
152 | our @destroy; |
402 | our @destroy; |
153 | our $manager; |
403 | our $manager; |
154 | |
404 | |
155 | $manager = new Coro sub { |
405 | $manager = new Coro sub { |
156 | while () { |
406 | while () { |
157 | Coro::State::cancel shift @destroy |
407 | _destroy shift @destroy |
158 | while @destroy; |
408 | while @destroy; |
159 | |
409 | |
160 | &schedule; |
410 | &schedule; |
161 | } |
411 | } |
162 | }; |
412 | }; |
… | |
… | |
296 | coro, regardless of priority. This is useful sometimes to ensure |
546 | coro, regardless of priority. This is useful sometimes to ensure |
297 | progress is made. |
547 | progress is made. |
298 | |
548 | |
299 | =item terminate [arg...] |
549 | =item terminate [arg...] |
300 | |
550 | |
301 | Terminates the current coro with the given status values (see L<cancel>). |
551 | Terminates the current coro with the given status values (see |
|
|
552 | L<cancel>). The values will not be copied, but referenced directly. |
302 | |
553 | |
303 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
554 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
304 | |
555 | |
305 | These function install enter and leave winders in the current scope. The |
556 | These function install enter and leave winders in the current scope. The |
306 | enter block will be executed when on_enter is called and whenever the |
557 | enter block will be executed when on_enter is called and whenever the |
… | |
… | |
480 | Returns true iff this Coro object has been suspended. Suspended Coros will |
731 | Returns true iff this Coro object has been suspended. Suspended Coros will |
481 | not ever be scheduled. |
732 | not ever be scheduled. |
482 | |
733 | |
483 | =item $coro->cancel (arg...) |
734 | =item $coro->cancel (arg...) |
484 | |
735 | |
485 | Terminates the given Coro and makes it return the given arguments as |
736 | Terminates the given Coro thread and makes it return the given arguments as |
486 | status (default: the empty list). Never returns if the Coro is the |
737 | status (default: an empty list). Never returns if the Coro is the |
487 | current Coro. |
738 | current Coro. |
488 | |
739 | |
489 | =cut |
740 | This is a rather brutal way to free a coro, with some limitations - if |
|
|
741 | the thread is inside a C callback that doesn't expect to be canceled, |
|
|
742 | bad things can happen, or if the cancelled thread insists on running |
|
|
743 | complicated cleanup handlers that rely on it'S thread context, things will |
|
|
744 | not work. |
490 | |
745 | |
491 | sub cancel { |
746 | Any cleanup code being run (e.g. from C<guard> blocks) will be run without |
492 | my $self = shift; |
747 | a thread context, and is not allowed to switch to other threads. On the |
|
|
748 | plus side, C<< ->cancel >> will always clean up the thread, no matter |
|
|
749 | what. If your cleanup code is complex or you want to avoid cancelling a |
|
|
750 | C-thread that doesn't know how to clean up itself, it can be better to C<< |
|
|
751 | ->throw >> an exception, or use C<< ->safe_cancel >>. |
493 | |
752 | |
494 | if ($current == $self) { |
753 | The arguments to C<< ->cancel >> are not copied, but instead will |
495 | terminate @_; |
754 | be referenced directly (e.g. if you pass C<$var> and after the call |
496 | } else { |
755 | change that variable, then you might change the return values passed to |
497 | $self->{_status} = [@_]; |
756 | e.g. C<join>, so don't do that). |
498 | Coro::State::cancel $self; |
757 | |
|
|
758 | The resources of the Coro are usually freed (or destructed) before this |
|
|
759 | call returns, but this can be delayed for an indefinite amount of time, as |
|
|
760 | in some cases the manager thread has to run first to actually destruct the |
|
|
761 | Coro object. |
|
|
762 | |
|
|
763 | =item $coro->safe_cancel ($arg...) |
|
|
764 | |
|
|
765 | Works mostly like C<< ->cancel >>, but is inherently "safer", and |
|
|
766 | consequently, can fail with an exception in cases the thread is not in a |
|
|
767 | cancellable state. |
|
|
768 | |
|
|
769 | This method works a bit like throwing an exception that cannot be caught |
|
|
770 | - specifically, it will clean up the thread from within itself, so |
|
|
771 | all cleanup handlers (e.g. C<guard> blocks) are run with full thread |
|
|
772 | context and can block if they wish. The downside is that there is no |
|
|
773 | guarantee that the thread can be cancelled when you call this method, and |
|
|
774 | therefore, it might fail. It is also considerably slower than C<cancel> or |
|
|
775 | C<terminate>. |
|
|
776 | |
|
|
777 | A thread is in a safe-cancellable state if it either hasn't been run yet, |
|
|
778 | or it has no C context attached and is inside an SLF function. |
|
|
779 | |
|
|
780 | The latter two basically mean that the thread isn't currently inside a |
|
|
781 | perl callback called from some C function (usually via some XS modules) |
|
|
782 | and isn't currently executing inside some C function itself (via Coro's XS |
|
|
783 | API). |
|
|
784 | |
|
|
785 | This call returns true when it could cancel the thread, or croaks with an |
|
|
786 | error otherwise (i.e. it either returns true or doesn't return at all). |
|
|
787 | |
|
|
788 | Why the weird interface? Well, there are two common models on how and |
|
|
789 | when to cancel things. In the first, you have the expectation that your |
|
|
790 | coro thread can be cancelled when you want to cancel it - if the thread |
|
|
791 | isn't cancellable, this would be a bug somewhere, so C<< ->safe_cancel >> |
|
|
792 | croaks to notify of the bug. |
|
|
793 | |
|
|
794 | In the second model you sometimes want to ask nicely to cancel a thread, |
|
|
795 | but if it's not a good time, well, then don't cancel. This can be done |
|
|
796 | relatively easy like this: |
|
|
797 | |
|
|
798 | if (! eval { $coro->safe_cancel }) { |
|
|
799 | warn "unable to cancel thread: $@"; |
499 | } |
800 | } |
500 | } |
801 | |
|
|
802 | However, what you never should do is first try to cancel "safely" and |
|
|
803 | if that fails, cancel the "hard" way with C<< ->cancel >>. That makes |
|
|
804 | no sense: either you rely on being able to execute cleanup code in your |
|
|
805 | thread context, or you don't. If you do, then C<< ->safe_cancel >> is the |
|
|
806 | only way, and if you don't, then C<< ->cancel >> is always faster and more |
|
|
807 | direct. |
501 | |
808 | |
502 | =item $coro->schedule_to |
809 | =item $coro->schedule_to |
503 | |
810 | |
504 | Puts the current coro to sleep (like C<Coro::schedule>), but instead |
811 | Puts the current coro to sleep (like C<Coro::schedule>), but instead |
505 | of continuing with the next coro from the ready queue, always switch to |
812 | of continuing with the next coro from the ready queue, always switch to |
… | |
… | |
524 | inside the coro at the next convenient point in time. Otherwise |
831 | inside the coro at the next convenient point in time. Otherwise |
525 | clears the exception object. |
832 | clears the exception object. |
526 | |
833 | |
527 | Coro will check for the exception each time a schedule-like-function |
834 | Coro will check for the exception each time a schedule-like-function |
528 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
835 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
529 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
836 | >>, C<< Coro::Handle->readable >> and so on. Most of those functions (all |
530 | detect this case and return early in case an exception is pending. |
837 | that are part of Coro itself) detect this case and return early in case an |
|
|
838 | exception is pending. |
531 | |
839 | |
532 | The exception object will be thrown "as is" with the specified scalar in |
840 | The exception object will be thrown "as is" with the specified scalar in |
533 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
841 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
534 | (unlike with C<die>). |
842 | (unlike with C<die>). |
535 | |
843 | |
536 | This can be used as a softer means than C<cancel> to ask a coro to |
844 | This can be used as a softer means than either C<cancel> or C<safe_cancel |
537 | end itself, although there is no guarantee that the exception will lead to |
845 | >to ask a coro to end itself, although there is no guarantee that the |
538 | termination, and if the exception isn't caught it might well end the whole |
846 | exception will lead to termination, and if the exception isn't caught it |
539 | program. |
847 | might well end the whole program. |
540 | |
848 | |
541 | You might also think of C<throw> as being the moral equivalent of |
849 | You might also think of C<throw> as being the moral equivalent of |
542 | C<kill>ing a coro with a signal (in this case, a scalar). |
850 | C<kill>ing a coro with a signal (in this case, a scalar). |
543 | |
851 | |
544 | =item $coro->join |
852 | =item $coro->join |
545 | |
853 | |
546 | Wait until the coro terminates and return any values given to the |
854 | Wait until the coro terminates and return any values given to the |
547 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
855 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
548 | from multiple coro, and all will be resumed and given the status |
856 | from multiple threads, and all will be resumed and given the status |
549 | return once the C<$coro> terminates. |
857 | return once the C<$coro> terminates. |
550 | |
858 | |
551 | =cut |
859 | =cut |
552 | |
860 | |
553 | sub join { |
861 | sub join { |
… | |
… | |
562 | }; |
870 | }; |
563 | |
871 | |
564 | &schedule while $current; |
872 | &schedule while $current; |
565 | } |
873 | } |
566 | |
874 | |
567 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
875 | wantarray ? @{$self->{_status}} : $self->{_status}[0] |
568 | } |
876 | } |
569 | |
877 | |
570 | =item $coro->on_destroy (\&cb) |
878 | =item $coro->on_destroy (\&cb) |
571 | |
879 | |
572 | Registers a callback that is called when this coro gets destroyed, |
880 | Registers a callback that is called when this coro thread gets destroyed, |
573 | but before it is joined. The callback gets passed the terminate arguments, |
881 | that is, after it's resources have been freed but before it is joined. The |
|
|
882 | callback gets passed the terminate/cancel arguments, if any, and I<must |
574 | if any, and I<must not> die, under any circumstances. |
883 | not> die, under any circumstances. |
|
|
884 | |
|
|
885 | There can be any number of C<on_destroy> callbacks per coro, and there is |
|
|
886 | no way currently to remove a callback once added. |
575 | |
887 | |
576 | =cut |
888 | =cut |
577 | |
889 | |
578 | sub on_destroy { |
890 | sub on_destroy { |
579 | my ($self, $cb) = @_; |
891 | my ($self, $cb) = @_; |
… | |
… | |
582 | } |
894 | } |
583 | |
895 | |
584 | =item $oldprio = $coro->prio ($newprio) |
896 | =item $oldprio = $coro->prio ($newprio) |
585 | |
897 | |
586 | Sets (or gets, if the argument is missing) the priority of the |
898 | Sets (or gets, if the argument is missing) the priority of the |
587 | coro. Higher priority coro get run before lower priority |
899 | coro thread. Higher priority coro get run before lower priority |
588 | coro. Priorities are small signed integers (currently -4 .. +3), |
900 | coros. Priorities are small signed integers (currently -4 .. +3), |
589 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
901 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
590 | to get then): |
902 | to get then): |
591 | |
903 | |
592 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
904 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
593 | 3 > 1 > 0 > -1 > -3 > -4 |
905 | 3 > 1 > 0 > -1 > -3 > -4 |
594 | |
906 | |
595 | # set priority to HIGH |
907 | # set priority to HIGH |
596 | current->prio (PRIO_HIGH); |
908 | current->prio (PRIO_HIGH); |
597 | |
909 | |
598 | The idle coro ($Coro::idle) always has a lower priority than any |
910 | The idle coro thread ($Coro::idle) always has a lower priority than any |
599 | existing coro. |
911 | existing coro. |
600 | |
912 | |
601 | Changing the priority of the current coro will take effect immediately, |
913 | Changing the priority of the current coro will take effect immediately, |
602 | but changing the priority of coro in the ready queue (but not |
914 | but changing the priority of a coro in the ready queue (but not running) |
603 | running) will only take effect after the next schedule (of that |
915 | will only take effect after the next schedule (of that coro). This is a |
604 | coro). This is a bug that will be fixed in some future version. |
916 | bug that will be fixed in some future version. |
605 | |
917 | |
606 | =item $newprio = $coro->nice ($change) |
918 | =item $newprio = $coro->nice ($change) |
607 | |
919 | |
608 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
920 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
609 | higher values mean lower priority, just as in unix). |
921 | higher values mean lower priority, just as in UNIX's nice command). |
610 | |
922 | |
611 | =item $olddesc = $coro->desc ($newdesc) |
923 | =item $olddesc = $coro->desc ($newdesc) |
612 | |
924 | |
613 | Sets (or gets in case the argument is missing) the description for this |
925 | Sets (or gets in case the argument is missing) the description for this |
614 | coro. This is just a free-form string you can associate with a |
926 | coro thread. This is just a free-form string you can associate with a |
615 | coro. |
927 | coro. |
616 | |
928 | |
617 | This method simply sets the C<< $coro->{desc} >> member to the given |
929 | This method simply sets the C<< $coro->{desc} >> member to the given |
618 | string. You can modify this member directly if you wish. |
930 | string. You can modify this member directly if you wish, and in fact, this |
|
|
931 | is often preferred to indicate major processing states that cna then be |
|
|
932 | seen for example in a L<Coro::Debug> session: |
|
|
933 | |
|
|
934 | sub my_long_function { |
|
|
935 | local $Coro::current->{desc} = "now in my_long_function"; |
|
|
936 | ... |
|
|
937 | $Coro::current->{desc} = "my_long_function: phase 1"; |
|
|
938 | ... |
|
|
939 | $Coro::current->{desc} = "my_long_function: phase 2"; |
|
|
940 | ... |
|
|
941 | } |
619 | |
942 | |
620 | =cut |
943 | =cut |
621 | |
944 | |
622 | sub desc { |
945 | sub desc { |
623 | my $old = $_[0]{desc}; |
946 | my $old = $_[0]{desc}; |
… | |
… | |
660 | returning a new coderef. Unblocking means that calling the new coderef |
983 | returning a new coderef. Unblocking means that calling the new coderef |
661 | will return immediately without blocking, returning nothing, while the |
984 | will return immediately without blocking, returning nothing, while the |
662 | original code ref will be called (with parameters) from within another |
985 | original code ref will be called (with parameters) from within another |
663 | coro. |
986 | coro. |
664 | |
987 | |
665 | The reason this function exists is that many event libraries (such as the |
988 | The reason this function exists is that many event libraries (such as |
666 | venerable L<Event|Event> module) are not thread-safe (a weaker form |
989 | the venerable L<Event|Event> module) are not thread-safe (a weaker form |
667 | of reentrancy). This means you must not block within event callbacks, |
990 | of reentrancy). This means you must not block within event callbacks, |
668 | otherwise you might suffer from crashes or worse. The only event library |
991 | otherwise you might suffer from crashes or worse. The only event library |
669 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
992 | currently known that is safe to use without C<unblock_sub> is L<EV> (but |
|
|
993 | you might still run into deadlocks if all event loops are blocked). |
670 | |
994 | |
671 | Coro will try to catch you when you block in the event loop |
995 | Coro will try to catch you when you block in the event loop |
672 | ("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and |
996 | ("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and |
673 | only works when you do not run your own event loop. |
997 | only works when you do not run your own event loop. |
674 | |
998 | |
… | |
… | |
745 | |
1069 | |
746 | =back |
1070 | =back |
747 | |
1071 | |
748 | =cut |
1072 | =cut |
749 | |
1073 | |
|
|
1074 | for my $module (qw(Channel RWLock Semaphore SemaphoreSet Signal Specific)) { |
|
|
1075 | my $old = defined &{"Coro::$module\::new"} && \&{"Coro::$module\::new"}; |
|
|
1076 | |
|
|
1077 | *{"Coro::$module\::new"} = sub { |
|
|
1078 | require "Coro/$module.pm"; |
|
|
1079 | |
|
|
1080 | # some modules have their new predefined in State.xs, some don't |
|
|
1081 | *{"Coro::$module\::new"} = $old |
|
|
1082 | if $old; |
|
|
1083 | |
|
|
1084 | goto &{"Coro::$module\::new"}; |
|
|
1085 | }; |
|
|
1086 | } |
|
|
1087 | |
750 | 1; |
1088 | 1; |
751 | |
1089 | |
752 | =head1 HOW TO WAIT FOR A CALLBACK |
1090 | =head1 HOW TO WAIT FOR A CALLBACK |
753 | |
1091 | |
754 | It is very common for a coro to wait for some callback to be |
1092 | It is very common for a coro to wait for some callback to be |
… | |
… | |
857 | ithreads (for example, that memory or files would be shared), showing his |
1195 | ithreads (for example, that memory or files would be shared), showing his |
858 | lack of understanding of this area - if it is hard to understand for Chip, |
1196 | lack of understanding of this area - if it is hard to understand for Chip, |
859 | it is probably not obvious to everybody). |
1197 | it is probably not obvious to everybody). |
860 | |
1198 | |
861 | What follows is an ultra-condensed version of my talk about threads in |
1199 | What follows is an ultra-condensed version of my talk about threads in |
862 | scripting languages given onthe perl workshop 2009: |
1200 | scripting languages given on the perl workshop 2009: |
863 | |
1201 | |
864 | The so-called "ithreads" were originally implemented for two reasons: |
1202 | The so-called "ithreads" were originally implemented for two reasons: |
865 | first, to (badly) emulate unix processes on native win32 perls, and |
1203 | first, to (badly) emulate unix processes on native win32 perls, and |
866 | secondly, to replace the older, real thread model ("5.005-threads"). |
1204 | secondly, to replace the older, real thread model ("5.005-threads"). |
867 | |
1205 | |