… | |
… | |
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 |
|
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70 | |
|
|
71 | During the long and exciting (or not) life of a coro thread, it goes |
|
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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 | |
|
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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; |
|
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91 | |
|
|
92 | This creates a new coro thread and puts it into the ready queue, meaning |
|
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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 |
|
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96 | reference or ignore it, the thread itself will keep a reference to it's |
|
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97 | thread object - threads are alive on their own. |
|
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98 | |
|
|
99 | Another way to create a thread is to call the C<new> constructor with a |
|
|
100 | code-reference: |
|
|
101 | |
|
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102 | new Coro sub { |
|
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103 | # thread code goes here |
|
|
104 | }, @optional_arguments; |
|
|
105 | |
|
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106 | This is quite similar to calling C<async>, but the important difference is |
|
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107 | that the new thread is not put into the ready queue, so the thread will |
|
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108 | not run until somebody puts it there. C<async> is, therefore, identical to |
|
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109 | this sequence: |
|
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110 | |
|
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111 | my $coro = new Coro sub { |
|
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112 | # thread code goes here |
|
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113 | }; |
|
|
114 | $coro->ready; |
|
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115 | return $coro; |
|
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116 | |
|
|
117 | =item 2. Startup |
|
|
118 | |
|
|
119 | When a new coro thread is created, only a copy of the code reference |
|
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120 | and the arguments are stored, no extra memory for stacks and so on is |
|
|
121 | allocated, keeping the coro thread in a low-memory state. |
|
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122 | |
|
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123 | Only when it actually starts executing will all the resources be finally |
|
|
124 | allocated. |
|
|
125 | |
|
|
126 | The optional arguments specified at coro creation are available in C<@_>, |
|
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127 | similar to function calls. |
|
|
128 | |
|
|
129 | =item 3. Running / Blocking |
|
|
130 | |
|
|
131 | A lot can happen after the coro thread has started running. Quite usually, |
|
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132 | it will not run to the end in one go (because you could use a function |
|
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133 | instead), but it will give up the CPU regularly because it waits for |
|
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134 | external events. |
|
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135 | |
|
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136 | As long as a coro thread runs, it's coro object is available in the global |
|
|
137 | variable C<$Coro::current>. |
|
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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: |
|
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141 | |
|
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142 | Coro::schedule; |
|
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143 | |
|
|
144 | Since running threads are not in the ready queue, calling the scheduler |
|
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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 |
|
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147 | event or some other thread, or you can put it into the ready queue before |
|
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148 | scheduling: |
|
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149 | |
|
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150 | # this is exactly what Coro::cede does |
|
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151 | $Coro::current->ready; |
|
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152 | Coro::schedule; |
|
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153 | |
|
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154 | All the higher-level synchronisation methods (Coro::Semaphore, |
|
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155 | Coro::rouse_*...) are actually implemented via C<< ->ready >> and C<< |
|
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156 | Coro::schedule >>. |
|
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157 | |
|
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158 | While the coro thread is running it also might get assigned a C-level |
|
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159 | thread, or the C-level thread might be unassigned from it, as the Coro |
|
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160 | runtime wishes. A C-level thread needs to be assigned when your perl |
|
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161 | thread calls into some C-level function and that function in turn calls |
|
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162 | perl and perl then wants to switch coroutines. This happens most often |
|
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163 | when you run an event loop and block in the callback, or when perl |
|
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164 | itself calls some function such as C<AUTOLOAD> or methods via the C<tie> |
|
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165 | mechanism. |
|
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166 | |
|
|
167 | =item 4. Termination |
|
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168 | |
|
|
169 | Many threads actually terminate after some time. There are a number of |
|
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170 | ways to terminate a coro thread, the simplest is returning from the |
|
|
171 | top-level code reference: |
|
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172 | |
|
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173 | async { |
|
|
174 | # after returning from here, the coro thread is terminated |
|
|
175 | }; |
|
|
176 | |
|
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177 | async { |
|
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178 | return if 0.5 < rand; # terminate a little earlier, maybe |
|
|
179 | print "got a chance to print this\n"; |
|
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180 | # or here |
|
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181 | }; |
|
|
182 | |
|
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183 | Any values returned from the coroutine can be recovered using C<< ->join |
|
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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 { |
|
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205 | exit 1; |
|
|
206 | }; |
|
|
207 | |
|
|
208 | $coro->cancel; # an also accept values for ->join to retrieve |
|
|
209 | |
|
|
210 | Cancellation I<can> be dangerous - it's a bit like calling C<exit> |
|
|
211 | without actually exiting, and might leave C libraries and XS modules in |
|
|
212 | a weird state. Unlike other thread implementations, however, Coro is |
|
|
213 | exceptionally safe with regards to cancellation, as perl will always be |
|
|
214 | in a consistent state, and for those cases where you want to do truly |
|
|
215 | marvellous things with your coro while it is being cancelled, there is |
|
|
216 | even a C<< ->safe_cancel >> method. |
|
|
217 | |
|
|
218 | So, cancelling a thread that runs in an XS event loop might not be the |
|
|
219 | best idea, but any other combination that deals with perl only (cancelling |
|
|
220 | when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is |
|
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221 | safe. |
|
|
222 | |
|
|
223 | =item 5. Cleanup |
|
|
224 | |
|
|
225 | Threads will allocate various resources. Most but not all will be returned |
|
|
226 | when a thread terminates, during clean-up. |
|
|
227 | |
|
|
228 | Cleanup is quite similar to throwing an uncaught exception: perl will |
|
|
229 | work it's way up through all subroutine calls and blocks. On it's way, it |
|
|
230 | will release all C<my> variables, undo all C<local>'s and free any other |
|
|
231 | resources truly local to the thread. |
|
|
232 | |
|
|
233 | So, a common way to free resources is to keep them referenced only by my |
|
|
234 | variables: |
|
|
235 | |
|
|
236 | async { |
|
|
237 | my $big_cache = new Cache ...; |
|
|
238 | }; |
|
|
239 | |
|
|
240 | If there are no other references, then the C<$big_cache> object will be |
|
|
241 | freed when the thread terminates, regardless of how it does so. |
|
|
242 | |
|
|
243 | What it does C<NOT> do is unlock any Coro::Semaphores or similar |
|
|
244 | resources, but that's where the C<guard> methods come in handy: |
|
|
245 | |
|
|
246 | my $sem = new Coro::Semaphore; |
|
|
247 | |
|
|
248 | async { |
|
|
249 | my $lock_guard = $sem->guard; |
|
|
250 | # if we reutrn, or die or get cancelled, here, |
|
|
251 | # then the semaphore will be "up"ed. |
|
|
252 | }; |
|
|
253 | |
|
|
254 | The C<Guard::guard> function comes in handy for any custom cleanup you |
|
|
255 | might want to do: |
|
|
256 | |
|
|
257 | async { |
|
|
258 | my $window = new Gtk2::Window "toplevel"; |
|
|
259 | # The window will not be cleaned up automatically, even when $window |
|
|
260 | # gets freed, so use a guard to ensure it's destruction |
|
|
261 | # in case of an error: |
|
|
262 | my $window_guard = Guard::guard { $window->destroy }; |
|
|
263 | |
|
|
264 | # we are safe here |
|
|
265 | }; |
|
|
266 | |
|
|
267 | Last not least, C<local> can often be handy, too, e.g. when temporarily |
|
|
268 | replacing the coro thread description: |
|
|
269 | |
|
|
270 | sub myfunction { |
|
|
271 | local $Coro::current->{desc} = "inside myfunction(@_)"; |
|
|
272 | |
|
|
273 | # if we return or die here, the description will be restored |
|
|
274 | } |
|
|
275 | |
|
|
276 | =item 6. Viva La Zombie Muerte |
|
|
277 | |
|
|
278 | Even after a thread has terminated and cleaned up it's resources, the coro |
|
|
279 | object still is there and stores the return values of the thread. Only in |
|
|
280 | this state will the coro object be "reference counted" in the normal perl |
|
|
281 | sense: the thread code keeps a reference to it when it is active, but not |
|
|
282 | after it has terminated. |
|
|
283 | |
|
|
284 | The means the coro object gets freed automatically when the thread has |
|
|
285 | terminated and cleaned up and there arenot other references. |
|
|
286 | |
|
|
287 | If there are, the coro object will stay around, and you can call C<< |
|
|
288 | ->join >> as many times as you wish to retrieve the result values: |
|
|
289 | |
|
|
290 | async { |
|
|
291 | print "hi\n"; |
|
|
292 | 1 |
|
|
293 | }; |
|
|
294 | |
|
|
295 | # run the async above, and free everything before returning |
|
|
296 | # from Coro::cede: |
|
|
297 | Coro::cede; |
|
|
298 | |
|
|
299 | { |
|
|
300 | my $coro = async { |
|
|
301 | print "hi\n"; |
|
|
302 | 1 |
|
|
303 | }; |
|
|
304 | |
|
|
305 | # run the async above, and clean up, but do not free the coro |
|
|
306 | # object: |
|
|
307 | Coro::cede; |
|
|
308 | |
|
|
309 | # optionally retrieve the result values |
|
|
310 | my @results = $coro->join; |
|
|
311 | |
|
|
312 | # now $coro goes out of scope, and presumably gets freed |
|
|
313 | }; |
|
|
314 | |
|
|
315 | =back |
|
|
316 | |
68 | =cut |
317 | =cut |
69 | |
318 | |
70 | package Coro; |
319 | package Coro; |
71 | |
320 | |
72 | use common::sense; |
321 | use common::sense; |
… | |
… | |
81 | |
330 | |
82 | our $idle; # idle handler |
331 | our $idle; # idle handler |
83 | our $main; # main coro |
332 | our $main; # main coro |
84 | our $current; # current coro |
333 | our $current; # current coro |
85 | |
334 | |
86 | our $VERSION = 5.21; |
335 | our $VERSION = 5.372; |
87 | |
336 | |
88 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
337 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
89 | our %EXPORT_TAGS = ( |
338 | our %EXPORT_TAGS = ( |
90 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
339 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
91 | ); |
340 | ); |
… | |
… | |
131 | |
380 | |
132 | The default implementation dies with "FATAL: deadlock detected.", followed |
381 | The default implementation dies with "FATAL: deadlock detected.", followed |
133 | by a thread listing, because the program has no other way to continue. |
382 | by a thread listing, because the program has no other way to continue. |
134 | |
383 | |
135 | This hook is overwritten by modules such as C<Coro::EV> and |
384 | 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 |
385 | C<Coro::AnyEvent> to wait on an external event that hopefully wakes up a |
137 | coro so the scheduler can run it. |
386 | coro so the scheduler can run it. |
138 | |
387 | |
139 | See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. |
388 | See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. |
140 | |
389 | |
141 | =cut |
390 | =cut |
142 | |
391 | |
|
|
392 | # ||= because other modules could have provided their own by now |
143 | $idle = new Coro sub { |
393 | $idle ||= new Coro sub { |
144 | require Coro::Debug; |
394 | require Coro::Debug; |
145 | die "FATAL: deadlock detected.\n" |
395 | die "FATAL: deadlock detected.\n" |
146 | . Coro::Debug::ps_listing (); |
396 | . Coro::Debug::ps_listing (); |
147 | }; |
397 | }; |
148 | |
398 | |
… | |
… | |
151 | our @destroy; |
401 | our @destroy; |
152 | our $manager; |
402 | our $manager; |
153 | |
403 | |
154 | $manager = new Coro sub { |
404 | $manager = new Coro sub { |
155 | while () { |
405 | while () { |
156 | Coro::State::cancel shift @destroy |
406 | _destroy shift @destroy |
157 | while @destroy; |
407 | while @destroy; |
158 | |
408 | |
159 | &schedule; |
409 | &schedule; |
160 | } |
410 | } |
161 | }; |
411 | }; |
… | |
… | |
295 | coro, regardless of priority. This is useful sometimes to ensure |
545 | coro, regardless of priority. This is useful sometimes to ensure |
296 | progress is made. |
546 | progress is made. |
297 | |
547 | |
298 | =item terminate [arg...] |
548 | =item terminate [arg...] |
299 | |
549 | |
300 | Terminates the current coro with the given status values (see L<cancel>). |
550 | Terminates the current coro with the given status values (see |
|
|
551 | L<cancel>). The values will not be copied, but referenced directly. |
301 | |
552 | |
302 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
553 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
303 | |
554 | |
304 | These function install enter and leave winders in the current scope. The |
555 | These function install enter and leave winders in the current scope. The |
305 | enter block will be executed when on_enter is called and whenever the |
556 | enter block will be executed when on_enter is called and whenever the |
… | |
… | |
479 | Returns true iff this Coro object has been suspended. Suspended Coros will |
730 | Returns true iff this Coro object has been suspended. Suspended Coros will |
480 | not ever be scheduled. |
731 | not ever be scheduled. |
481 | |
732 | |
482 | =item $coro->cancel (arg...) |
733 | =item $coro->cancel (arg...) |
483 | |
734 | |
484 | Terminates the given Coro and makes it return the given arguments as |
735 | Terminates the given Coro thread and makes it return the given arguments as |
485 | status (default: the empty list). Never returns if the Coro is the |
736 | status (default: an empty list). Never returns if the Coro is the |
486 | current Coro. |
737 | current Coro. |
487 | |
738 | |
488 | =cut |
739 | This is a rather brutal way to free a coro, with some limitations - if |
|
|
740 | the thread is inside a C callback that doesn't expect to be canceled, |
|
|
741 | bad things can happen, or if the cancelled thread insists on running |
|
|
742 | complicated cleanup handlers that rely on it'S thread context, things will |
|
|
743 | not work. |
489 | |
744 | |
490 | sub cancel { |
745 | Sometimes it is safer to C<< ->throw >> an exception, or use C<< |
491 | my $self = shift; |
746 | ->safe_cancel >>. |
492 | |
747 | |
493 | if ($current == $self) { |
748 | The arguments are not copied, but instead will be referenced directly |
494 | terminate @_; |
749 | (e.g. if you pass C<$var> and after the call change that variable, then |
495 | } else { |
750 | you might change the return values passed to e.g. C<join>, so don't do |
496 | $self->{_status} = [@_]; |
751 | that). |
497 | Coro::State::cancel $self; |
752 | |
|
|
753 | The resources of the Coro are usually freed (or destructed) before this |
|
|
754 | call returns, but this can be delayed for an indefinite amount of time, as |
|
|
755 | in some cases the manager thread has to run first to actually destruct the |
|
|
756 | Coro object. |
|
|
757 | |
|
|
758 | =item $coro->safe_cancel ($arg...) |
|
|
759 | |
|
|
760 | Works mostly like C<< ->cancel >>, but is inherently "safer", and |
|
|
761 | consequently, can fail with an exception in cases the thread is not in a |
|
|
762 | cancellable state. |
|
|
763 | |
|
|
764 | This method works a bit like throwing an exception that cannot be caught |
|
|
765 | - specifically, it will clean up the thread from within itself, so all |
|
|
766 | cleanup handlers (e.g. C<guard> blocks) are run with full thread context |
|
|
767 | and can block if they wish. |
|
|
768 | |
|
|
769 | A thread is safe-cancellable if it either hasn't been run yet, or |
|
|
770 | it has no C context attached and is inside an SLF function. |
|
|
771 | |
|
|
772 | The latter two basically mean that the thread isn't currently inside a |
|
|
773 | perl callback called from some C function (usually XS modules) and isn't |
|
|
774 | currently inside some C function itself. |
|
|
775 | |
|
|
776 | This call always returns true when it could cancel the thread, or croaks |
|
|
777 | with an error otherwise, so you can write things like this: |
|
|
778 | |
|
|
779 | if (! eval { $coro->safe_cancel }) { |
|
|
780 | warn "unable to cancel thread: $@"; |
498 | } |
781 | } |
499 | } |
|
|
500 | |
782 | |
501 | =item $coro->schedule_to |
783 | =item $coro->schedule_to |
502 | |
784 | |
503 | Puts the current coro to sleep (like C<Coro::schedule>), but instead |
785 | Puts the current coro to sleep (like C<Coro::schedule>), but instead |
504 | of continuing with the next coro from the ready queue, always switch to |
786 | of continuing with the next coro from the ready queue, always switch to |
… | |
… | |
542 | |
824 | |
543 | =item $coro->join |
825 | =item $coro->join |
544 | |
826 | |
545 | Wait until the coro terminates and return any values given to the |
827 | Wait until the coro terminates and return any values given to the |
546 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
828 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
547 | from multiple coro, and all will be resumed and given the status |
829 | from multiple threads, and all will be resumed and given the status |
548 | return once the C<$coro> terminates. |
830 | return once the C<$coro> terminates. |
549 | |
831 | |
550 | =cut |
832 | =cut |
551 | |
833 | |
552 | sub join { |
834 | sub join { |
… | |
… | |
566 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
848 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
567 | } |
849 | } |
568 | |
850 | |
569 | =item $coro->on_destroy (\&cb) |
851 | =item $coro->on_destroy (\&cb) |
570 | |
852 | |
571 | Registers a callback that is called when this coro gets destroyed, |
853 | Registers a callback that is called when this coro thread gets destroyed, |
572 | but before it is joined. The callback gets passed the terminate arguments, |
854 | that is, after it's resources have been freed but before it is joined. The |
|
|
855 | callback gets passed the terminate/cancel arguments, if any, and I<must |
573 | if any, and I<must not> die, under any circumstances. |
856 | not> die, under any circumstances. |
|
|
857 | |
|
|
858 | There can be any number of C<on_destroy> callbacks per coro, and there is |
|
|
859 | no way currently to remove a callback once added. |
574 | |
860 | |
575 | =cut |
861 | =cut |
576 | |
862 | |
577 | sub on_destroy { |
863 | sub on_destroy { |
578 | my ($self, $cb) = @_; |
864 | my ($self, $cb) = @_; |
… | |
… | |
581 | } |
867 | } |
582 | |
868 | |
583 | =item $oldprio = $coro->prio ($newprio) |
869 | =item $oldprio = $coro->prio ($newprio) |
584 | |
870 | |
585 | Sets (or gets, if the argument is missing) the priority of the |
871 | Sets (or gets, if the argument is missing) the priority of the |
586 | coro. Higher priority coro get run before lower priority |
872 | coro thread. Higher priority coro get run before lower priority |
587 | coro. Priorities are small signed integers (currently -4 .. +3), |
873 | coros. Priorities are small signed integers (currently -4 .. +3), |
588 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
874 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
589 | to get then): |
875 | to get then): |
590 | |
876 | |
591 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
877 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
592 | 3 > 1 > 0 > -1 > -3 > -4 |
878 | 3 > 1 > 0 > -1 > -3 > -4 |
593 | |
879 | |
594 | # set priority to HIGH |
880 | # set priority to HIGH |
595 | current->prio (PRIO_HIGH); |
881 | current->prio (PRIO_HIGH); |
596 | |
882 | |
597 | The idle coro ($Coro::idle) always has a lower priority than any |
883 | The idle coro thread ($Coro::idle) always has a lower priority than any |
598 | existing coro. |
884 | existing coro. |
599 | |
885 | |
600 | Changing the priority of the current coro will take effect immediately, |
886 | Changing the priority of the current coro will take effect immediately, |
601 | but changing the priority of coro in the ready queue (but not |
887 | but changing the priority of a coro in the ready queue (but not running) |
602 | running) will only take effect after the next schedule (of that |
888 | will only take effect after the next schedule (of that coro). This is a |
603 | coro). This is a bug that will be fixed in some future version. |
889 | bug that will be fixed in some future version. |
604 | |
890 | |
605 | =item $newprio = $coro->nice ($change) |
891 | =item $newprio = $coro->nice ($change) |
606 | |
892 | |
607 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
893 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
608 | higher values mean lower priority, just as in unix). |
894 | higher values mean lower priority, just as in UNIX's nice command). |
609 | |
895 | |
610 | =item $olddesc = $coro->desc ($newdesc) |
896 | =item $olddesc = $coro->desc ($newdesc) |
611 | |
897 | |
612 | Sets (or gets in case the argument is missing) the description for this |
898 | Sets (or gets in case the argument is missing) the description for this |
613 | coro. This is just a free-form string you can associate with a |
899 | coro thread. This is just a free-form string you can associate with a |
614 | coro. |
900 | coro. |
615 | |
901 | |
616 | This method simply sets the C<< $coro->{desc} >> member to the given |
902 | This method simply sets the C<< $coro->{desc} >> member to the given |
617 | string. You can modify this member directly if you wish. |
903 | string. You can modify this member directly if you wish, and in fact, this |
|
|
904 | is often preferred to indicate major processing states that cna then be |
|
|
905 | seen for example in a L<Coro::Debug> session: |
|
|
906 | |
|
|
907 | sub my_long_function { |
|
|
908 | local $Coro::current->{desc} = "now in my_long_function"; |
|
|
909 | ... |
|
|
910 | $Coro::current->{desc} = "my_long_function: phase 1"; |
|
|
911 | ... |
|
|
912 | $Coro::current->{desc} = "my_long_function: phase 2"; |
|
|
913 | ... |
|
|
914 | } |
618 | |
915 | |
619 | =cut |
916 | =cut |
620 | |
917 | |
621 | sub desc { |
918 | sub desc { |
622 | my $old = $_[0]{desc}; |
919 | my $old = $_[0]{desc}; |
… | |
… | |
659 | returning a new coderef. Unblocking means that calling the new coderef |
956 | returning a new coderef. Unblocking means that calling the new coderef |
660 | will return immediately without blocking, returning nothing, while the |
957 | will return immediately without blocking, returning nothing, while the |
661 | original code ref will be called (with parameters) from within another |
958 | original code ref will be called (with parameters) from within another |
662 | coro. |
959 | coro. |
663 | |
960 | |
664 | The reason this function exists is that many event libraries (such as the |
961 | The reason this function exists is that many event libraries (such as |
665 | venerable L<Event|Event> module) are not thread-safe (a weaker form |
962 | the venerable L<Event|Event> module) are not thread-safe (a weaker form |
666 | of reentrancy). This means you must not block within event callbacks, |
963 | of reentrancy). This means you must not block within event callbacks, |
667 | otherwise you might suffer from crashes or worse. The only event library |
964 | otherwise you might suffer from crashes or worse. The only event library |
668 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
965 | currently known that is safe to use without C<unblock_sub> is L<EV> (but |
|
|
966 | you might still run into deadlocks if all event loops are blocked). |
|
|
967 | |
|
|
968 | Coro will try to catch you when you block in the event loop |
|
|
969 | ("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and |
|
|
970 | only works when you do not run your own event loop. |
669 | |
971 | |
670 | This function allows your callbacks to block by executing them in another |
972 | This function allows your callbacks to block by executing them in another |
671 | coro where it is safe to block. One example where blocking is handy |
973 | coro where it is safe to block. One example where blocking is handy |
672 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
974 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
673 | disk, for example. |
975 | disk, for example. |
… | |
… | |
740 | |
1042 | |
741 | =back |
1043 | =back |
742 | |
1044 | |
743 | =cut |
1045 | =cut |
744 | |
1046 | |
|
|
1047 | for my $module (qw(Channel RWLock Semaphore SemaphoreSet Signal Specific)) { |
|
|
1048 | my $old = defined &{"Coro::$module\::new"} && \&{"Coro::$module\::new"}; |
|
|
1049 | |
|
|
1050 | *{"Coro::$module\::new"} = sub { |
|
|
1051 | require "Coro/$module.pm"; |
|
|
1052 | |
|
|
1053 | # some modules have their new predefined in State.xs, some don't |
|
|
1054 | *{"Coro::$module\::new"} = $old |
|
|
1055 | if $old; |
|
|
1056 | |
|
|
1057 | goto &{"Coro::$module\::new"}; |
|
|
1058 | }; |
|
|
1059 | } |
|
|
1060 | |
745 | 1; |
1061 | 1; |
746 | |
1062 | |
747 | =head1 HOW TO WAIT FOR A CALLBACK |
1063 | =head1 HOW TO WAIT FOR A CALLBACK |
748 | |
1064 | |
749 | It is very common for a coro to wait for some callback to be |
1065 | It is very common for a coro to wait for some callback to be |
… | |
… | |
852 | ithreads (for example, that memory or files would be shared), showing his |
1168 | ithreads (for example, that memory or files would be shared), showing his |
853 | lack of understanding of this area - if it is hard to understand for Chip, |
1169 | lack of understanding of this area - if it is hard to understand for Chip, |
854 | it is probably not obvious to everybody). |
1170 | it is probably not obvious to everybody). |
855 | |
1171 | |
856 | What follows is an ultra-condensed version of my talk about threads in |
1172 | What follows is an ultra-condensed version of my talk about threads in |
857 | scripting languages given onthe perl workshop 2009: |
1173 | scripting languages given on the perl workshop 2009: |
858 | |
1174 | |
859 | The so-called "ithreads" were originally implemented for two reasons: |
1175 | The so-called "ithreads" were originally implemented for two reasons: |
860 | first, to (badly) emulate unix processes on native win32 perls, and |
1176 | first, to (badly) emulate unix processes on native win32 perls, and |
861 | secondly, to replace the older, real thread model ("5.005-threads"). |
1177 | secondly, to replace the older, real thread model ("5.005-threads"). |
862 | |
1178 | |