1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - real threads in perl |
3 | Coro - the only real threads in perl |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
… | |
… | |
11 | print "2\n"; |
11 | print "2\n"; |
12 | cede; # yield back to main |
12 | cede; # yield back to main |
13 | print "4\n"; |
13 | print "4\n"; |
14 | }; |
14 | }; |
15 | print "1\n"; |
15 | print "1\n"; |
16 | cede; # yield to coroutine |
16 | cede; # yield to coro |
17 | print "3\n"; |
17 | print "3\n"; |
18 | cede; # and again |
18 | cede; # and again |
19 | |
19 | |
20 | # use locking |
20 | # use locking |
21 | use Coro::Semaphore; |
21 | use Coro::Semaphore; |
… | |
… | |
26 | $locked = 1; |
26 | $locked = 1; |
27 | $lock->up; |
27 | $lock->up; |
28 | |
28 | |
29 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
30 | |
30 | |
31 | This module collection manages coroutines, that is, cooperative |
31 | For a tutorial-style introduction, please read the L<Coro::Intro> |
32 | threads. Coroutines are similar to kernel threads but don't (in general) |
32 | manpage. This manpage mainly contains reference information. |
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33 | |
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34 | This module collection manages continuations in general, most often in |
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35 | the form of cooperative threads (also called coros, or simply "coro" |
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36 | in the documentation). They are similar to kernel threads but don't (in |
33 | run in parallel at the same time even on SMP machines. The specific flavor |
37 | general) run in parallel at the same time even on SMP machines. The |
34 | of coroutine used in this module also guarantees you that it will not |
38 | specific flavor of thread offered by this module also guarantees you that |
35 | switch between coroutines unless necessary, at easily-identified points |
39 | it will not switch between threads unless necessary, at easily-identified |
36 | in your program, so locking and parallel access are rarely an issue, |
40 | points in your program, so locking and parallel access are rarely an |
37 | making coroutine programming much safer and easier than using other thread |
41 | issue, making thread programming much safer and easier than using other |
38 | models. |
42 | thread models. |
39 | |
43 | |
40 | 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 |
41 | but only the windows process emulation ported to unix), Coro provides a |
45 | but only the windows process emulation (see section of same name for more |
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46 | details) ported to unix, and as such act as processes), Coro provides |
42 | full shared address space, which makes communication between coroutines |
47 | a full shared address space, which makes communication between threads |
43 | very easy. And coroutines are fast, too: disabling the Windows process |
48 | very easy. And Coro's threads are fast, too: disabling the Windows |
44 | emulation code in your perl and using Coro can easily result in a two to |
49 | process emulation code in your perl and using Coro can easily result in |
45 | four times speed increase for your programs. |
50 | a two to four times speed increase for your programs. A parallel matrix |
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51 | multiplication benchmark runs over 300 times faster on a single core than |
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52 | perl's pseudo-threads on a quad core using all four cores. |
46 | |
53 | |
47 | Coro achieves that by supporting multiple running interpreters that share |
54 | Coro achieves that by supporting multiple running interpreters that share |
48 | data, which is especially useful to code pseudo-parallel processes and |
55 | data, which is especially useful to code pseudo-parallel processes and |
49 | for event-based programming, such as multiple HTTP-GET requests running |
56 | for event-based programming, such as multiple HTTP-GET requests running |
50 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
57 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
51 | into an event-based environment. |
58 | into an event-based environment. |
52 | |
59 | |
53 | In this module, a coroutines is defined as "callchain + lexical variables |
60 | In this module, a thread is defined as "callchain + lexical variables + |
54 | + @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own |
61 | some package variables + C stack), that is, a thread has its own callchain, |
55 | callchain, its own set of lexicals and its own set of perls most important |
62 | its own set of lexicals and its own set of perls most important global |
56 | global variables (see L<Coro::State> for more configuration and background |
63 | variables (see L<Coro::State> for more configuration and background info). |
57 | info). |
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58 | |
64 | |
59 | See also the C<SEE ALSO> section at the end of this document - the Coro |
65 | See also the C<SEE ALSO> section at the end of this document - the Coro |
60 | module family is quite large. |
66 | module family is quite large. |
61 | |
67 | |
62 | =cut |
68 | =cut |
63 | |
69 | |
64 | package Coro; |
70 | package Coro; |
65 | |
71 | |
66 | use strict qw(vars subs); |
72 | use common::sense; |
67 | no warnings "uninitialized"; |
73 | |
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74 | use Carp (); |
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75 | |
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76 | use Guard (); |
68 | |
77 | |
69 | use Coro::State; |
78 | use Coro::State; |
70 | |
79 | |
71 | use base qw(Coro::State Exporter); |
80 | use base qw(Coro::State Exporter); |
72 | |
81 | |
73 | our $idle; # idle handler |
82 | our $idle; # idle handler |
74 | our $main; # main coroutine |
83 | our $main; # main coro |
75 | our $current; # current coroutine |
84 | our $current; # current coro |
76 | |
85 | |
77 | our $VERSION = "5.0"; |
86 | our $VERSION = 5.26; |
78 | |
87 | |
79 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
88 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait); |
80 | our %EXPORT_TAGS = ( |
89 | our %EXPORT_TAGS = ( |
81 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
90 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
82 | ); |
91 | ); |
83 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
92 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
84 | |
93 | |
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… | |
86 | |
95 | |
87 | =over 4 |
96 | =over 4 |
88 | |
97 | |
89 | =item $Coro::main |
98 | =item $Coro::main |
90 | |
99 | |
91 | This variable stores the coroutine object that represents the main |
100 | This variable stores the Coro object that represents the main |
92 | program. While you cna C<ready> it and do most other things you can do to |
101 | program. While you cna C<ready> it and do most other things you can do to |
93 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
102 | coro, it is mainly useful to compare again C<$Coro::current>, to see |
94 | whether you are running in the main program or not. |
103 | whether you are running in the main program or not. |
95 | |
104 | |
96 | =cut |
105 | =cut |
97 | |
106 | |
98 | # $main is now being initialised by Coro::State |
107 | # $main is now being initialised by Coro::State |
99 | |
108 | |
100 | =item $Coro::current |
109 | =item $Coro::current |
101 | |
110 | |
102 | The coroutine object representing the current coroutine (the last |
111 | The Coro object representing the current coro (the last |
103 | coroutine that the Coro scheduler switched to). The initial value is |
112 | coro that the Coro scheduler switched to). The initial value is |
104 | C<$Coro::main> (of course). |
113 | C<$Coro::main> (of course). |
105 | |
114 | |
106 | This variable is B<strictly> I<read-only>. You can take copies of the |
115 | This variable is B<strictly> I<read-only>. You can take copies of the |
107 | value stored in it and use it as any other coroutine object, but you must |
116 | value stored in it and use it as any other Coro object, but you must |
108 | not otherwise modify the variable itself. |
117 | not otherwise modify the variable itself. |
109 | |
118 | |
110 | =cut |
119 | =cut |
111 | |
120 | |
112 | sub current() { $current } # [DEPRECATED] |
121 | sub current() { $current } # [DEPRECATED] |
113 | |
122 | |
114 | =item $Coro::idle |
123 | =item $Coro::idle |
115 | |
124 | |
116 | This variable is mainly useful to integrate Coro into event loops. It is |
125 | This variable is mainly useful to integrate Coro into event loops. It is |
117 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
126 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
118 | pretty low-level functionality. |
127 | pretty low-level functionality. |
119 | |
128 | |
120 | This variable stores a callback that is called whenever the scheduler |
129 | This variable stores a Coro object that is put into the ready queue when |
121 | finds no ready coroutines to run. The default implementation prints |
130 | there are no other ready threads (without invoking any ready hooks). |
122 | "FATAL: deadlock detected" and exits, because the program has no other way |
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123 | to continue. |
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124 | |
131 | |
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132 | The default implementation dies with "FATAL: deadlock detected.", followed |
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133 | by a thread listing, because the program has no other way to continue. |
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134 | |
125 | This hook is overwritten by modules such as C<Coro::Timer> and |
135 | This hook is overwritten by modules such as C<Coro::EV> and |
126 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
136 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
127 | coroutine so the scheduler can run it. |
137 | coro so the scheduler can run it. |
128 | |
138 | |
129 | Note that the callback I<must not>, under any circumstances, block |
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130 | the current coroutine. Normally, this is achieved by having an "idle |
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131 | coroutine" that calls the event loop and then blocks again, and then |
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132 | readying that coroutine in the idle handler. |
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133 | |
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134 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
139 | See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique. |
135 | technique. |
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136 | |
140 | |
137 | Please note that if your callback recursively invokes perl (e.g. for event |
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138 | handlers), then it must be prepared to be called recursively itself. |
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139 | |
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140 | =cut |
141 | =cut |
141 | |
142 | |
142 | $idle = sub { |
143 | # ||= because other modules could have provided their own by now |
143 | require Carp; |
144 | $idle ||= new Coro sub { |
144 | Carp::croak ("FATAL: deadlock detected"); |
145 | require Coro::Debug; |
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146 | die "FATAL: deadlock detected.\n" |
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147 | . Coro::Debug::ps_listing (); |
145 | }; |
148 | }; |
146 | |
149 | |
147 | # this coroutine is necessary because a coroutine |
150 | # this coro is necessary because a coro |
148 | # cannot destroy itself. |
151 | # cannot destroy itself. |
149 | our @destroy; |
152 | our @destroy; |
150 | our $manager; |
153 | our $manager; |
151 | |
154 | |
152 | $manager = new Coro sub { |
155 | $manager = new Coro sub { |
153 | while () { |
156 | while () { |
154 | Coro::_cancel shift @destroy |
157 | Coro::State::cancel shift @destroy |
155 | while @destroy; |
158 | while @destroy; |
156 | |
159 | |
157 | &schedule; |
160 | &schedule; |
158 | } |
161 | } |
159 | }; |
162 | }; |
160 | $manager->{desc} = "[coro manager]"; |
163 | $manager->{desc} = "[coro manager]"; |
161 | $manager->prio (PRIO_MAX); |
164 | $manager->prio (PRIO_MAX); |
162 | |
165 | |
163 | =back |
166 | =back |
164 | |
167 | |
165 | =head1 SIMPLE COROUTINE CREATION |
168 | =head1 SIMPLE CORO CREATION |
166 | |
169 | |
167 | =over 4 |
170 | =over 4 |
168 | |
171 | |
169 | =item async { ... } [@args...] |
172 | =item async { ... } [@args...] |
170 | |
173 | |
171 | Create a new coroutine and return it's coroutine object (usually |
174 | Create a new coro and return its Coro object (usually |
172 | unused). The coroutine will be put into the ready queue, so |
175 | unused). The coro will be put into the ready queue, so |
173 | it will start running automatically on the next scheduler run. |
176 | it will start running automatically on the next scheduler run. |
174 | |
177 | |
175 | The first argument is a codeblock/closure that should be executed in the |
178 | The first argument is a codeblock/closure that should be executed in the |
176 | coroutine. When it returns argument returns the coroutine is automatically |
179 | coro. When it returns argument returns the coro is automatically |
177 | terminated. |
180 | terminated. |
178 | |
181 | |
179 | The remaining arguments are passed as arguments to the closure. |
182 | The remaining arguments are passed as arguments to the closure. |
180 | |
183 | |
181 | See the C<Coro::State::new> constructor for info about the coroutine |
184 | See the C<Coro::State::new> constructor for info about the coro |
182 | environment in which coroutines are executed. |
185 | environment in which coro are executed. |
183 | |
186 | |
184 | Calling C<exit> in a coroutine will do the same as calling exit outside |
187 | Calling C<exit> in a coro will do the same as calling exit outside |
185 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
188 | the coro. Likewise, when the coro dies, the program will exit, |
186 | just as it would in the main program. |
189 | just as it would in the main program. |
187 | |
190 | |
188 | If you do not want that, you can provide a default C<die> handler, or |
191 | If you do not want that, you can provide a default C<die> handler, or |
189 | simply avoid dieing (by use of C<eval>). |
192 | simply avoid dieing (by use of C<eval>). |
190 | |
193 | |
191 | Example: Create a new coroutine that just prints its arguments. |
194 | Example: Create a new coro that just prints its arguments. |
192 | |
195 | |
193 | async { |
196 | async { |
194 | print "@_\n"; |
197 | print "@_\n"; |
195 | } 1,2,3,4; |
198 | } 1,2,3,4; |
196 | |
199 | |
197 | =cut |
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198 | |
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199 | sub async(&@) { |
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200 | my $coro = new Coro @_; |
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201 | $coro->ready; |
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202 | $coro |
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203 | } |
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204 | |
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205 | =item async_pool { ... } [@args...] |
200 | =item async_pool { ... } [@args...] |
206 | |
201 | |
207 | Similar to C<async>, but uses a coroutine pool, so you should not call |
202 | Similar to C<async>, but uses a coro pool, so you should not call |
208 | terminate or join on it (although you are allowed to), and you get a |
203 | terminate or join on it (although you are allowed to), and you get a |
209 | coroutine that might have executed other code already (which can be good |
204 | coro that might have executed other code already (which can be good |
210 | or bad :). |
205 | or bad :). |
211 | |
206 | |
212 | On the plus side, this function is about twice as fast as creating (and |
207 | On the plus side, this function is about twice as fast as creating (and |
213 | destroying) a completely new coroutine, so if you need a lot of generic |
208 | destroying) a completely new coro, so if you need a lot of generic |
214 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
209 | coros in quick successsion, use C<async_pool>, not C<async>. |
215 | |
210 | |
216 | The code block is executed in an C<eval> context and a warning will be |
211 | The code block is executed in an C<eval> context and a warning will be |
217 | issued in case of an exception instead of terminating the program, as |
212 | issued in case of an exception instead of terminating the program, as |
218 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
213 | C<async> does. As the coro is being reused, stuff like C<on_destroy> |
219 | will not work in the expected way, unless you call terminate or cancel, |
214 | will not work in the expected way, unless you call terminate or cancel, |
220 | which somehow defeats the purpose of pooling (but is fine in the |
215 | which somehow defeats the purpose of pooling (but is fine in the |
221 | exceptional case). |
216 | exceptional case). |
222 | |
217 | |
223 | The priority will be reset to C<0> after each run, tracing will be |
218 | The priority will be reset to C<0> after each run, tracing will be |
224 | disabled, the description will be reset and the default output filehandle |
219 | disabled, the description will be reset and the default output filehandle |
225 | gets restored, so you can change all these. Otherwise the coroutine will |
220 | gets restored, so you can change all these. Otherwise the coro will |
226 | be re-used "as-is": most notably if you change other per-coroutine global |
221 | be re-used "as-is": most notably if you change other per-coro global |
227 | stuff such as C<$/> you I<must needs> revert that change, which is most |
222 | stuff such as C<$/> you I<must needs> revert that change, which is most |
228 | simply done by using local as in: C<< local $/ >>. |
223 | simply done by using local as in: C<< local $/ >>. |
229 | |
224 | |
230 | The idle pool size is limited to C<8> idle coroutines (this can be |
225 | The idle pool size is limited to C<8> idle coros (this can be |
231 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
226 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
232 | coros as required. |
227 | coros as required. |
233 | |
228 | |
234 | If you are concerned about pooled coroutines growing a lot because a |
229 | If you are concerned about pooled coros growing a lot because a |
235 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
230 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
236 | { terminate }> once per second or so to slowly replenish the pool. In |
231 | { terminate }> once per second or so to slowly replenish the pool. In |
237 | addition to that, when the stacks used by a handler grows larger than 32kb |
232 | addition to that, when the stacks used by a handler grows larger than 32kb |
238 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
233 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
239 | |
234 | |
… | |
… | |
256 | =back |
251 | =back |
257 | |
252 | |
258 | =head1 STATIC METHODS |
253 | =head1 STATIC METHODS |
259 | |
254 | |
260 | Static methods are actually functions that implicitly operate on the |
255 | Static methods are actually functions that implicitly operate on the |
261 | current coroutine. |
256 | current coro. |
262 | |
257 | |
263 | =over 4 |
258 | =over 4 |
264 | |
259 | |
265 | =item schedule |
260 | =item schedule |
266 | |
261 | |
267 | Calls the scheduler. The scheduler will find the next coroutine that is |
262 | Calls the scheduler. The scheduler will find the next coro that is |
268 | to be run from the ready queue and switches to it. The next coroutine |
263 | to be run from the ready queue and switches to it. The next coro |
269 | to be run is simply the one with the highest priority that is longest |
264 | to be run is simply the one with the highest priority that is longest |
270 | in its ready queue. If there is no coroutine ready, it will clal the |
265 | in its ready queue. If there is no coro ready, it will call the |
271 | C<$Coro::idle> hook. |
266 | C<$Coro::idle> hook. |
272 | |
267 | |
273 | Please note that the current coroutine will I<not> be put into the ready |
268 | Please note that the current coro will I<not> be put into the ready |
274 | queue, so calling this function usually means you will never be called |
269 | queue, so calling this function usually means you will never be called |
275 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
270 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
276 | thus waking you up. |
271 | thus waking you up. |
277 | |
272 | |
278 | This makes C<schedule> I<the> generic method to use to block the current |
273 | This makes C<schedule> I<the> generic method to use to block the current |
279 | coroutine and wait for events: first you remember the current coroutine in |
274 | coro and wait for events: first you remember the current coro in |
280 | a variable, then arrange for some callback of yours to call C<< ->ready |
275 | a variable, then arrange for some callback of yours to call C<< ->ready |
281 | >> on that once some event happens, and last you call C<schedule> to put |
276 | >> on that once some event happens, and last you call C<schedule> to put |
282 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
277 | yourself to sleep. Note that a lot of things can wake your coro up, |
283 | so you need to check whether the event indeed happened, e.g. by storing the |
278 | so you need to check whether the event indeed happened, e.g. by storing the |
284 | status in a variable. |
279 | status in a variable. |
285 | |
280 | |
286 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
281 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
287 | |
282 | |
288 | =item cede |
283 | =item cede |
289 | |
284 | |
290 | "Cede" to other coroutines. This function puts the current coroutine into |
285 | "Cede" to other coros. This function puts the current coro into |
291 | the ready queue and calls C<schedule>, which has the effect of giving |
286 | the ready queue and calls C<schedule>, which has the effect of giving |
292 | up the current "timeslice" to other coroutines of the same or higher |
287 | up the current "timeslice" to other coros of the same or higher |
293 | priority. Once your coroutine gets its turn again it will automatically be |
288 | priority. Once your coro gets its turn again it will automatically be |
294 | resumed. |
289 | resumed. |
295 | |
290 | |
296 | This function is often called C<yield> in other languages. |
291 | This function is often called C<yield> in other languages. |
297 | |
292 | |
298 | =item Coro::cede_notself |
293 | =item Coro::cede_notself |
299 | |
294 | |
300 | Works like cede, but is not exported by default and will cede to I<any> |
295 | Works like cede, but is not exported by default and will cede to I<any> |
301 | coroutine, regardless of priority. This is useful sometimes to ensure |
296 | coro, regardless of priority. This is useful sometimes to ensure |
302 | progress is made. |
297 | progress is made. |
303 | |
298 | |
304 | =item terminate [arg...] |
299 | =item terminate [arg...] |
305 | |
300 | |
306 | Terminates the current coroutine with the given status values (see L<cancel>). |
301 | Terminates the current coro with the given status values (see L<cancel>). |
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302 | |
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303 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
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304 | |
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305 | These function install enter and leave winders in the current scope. The |
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306 | enter block will be executed when on_enter is called and whenever the |
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307 | current coro is re-entered by the scheduler, while the leave block is |
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308 | executed whenever the current coro is blocked by the scheduler, and |
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309 | also when the containing scope is exited (by whatever means, be it exit, |
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310 | die, last etc.). |
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311 | |
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312 | I<Neither invoking the scheduler, nor exceptions, are allowed within those |
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313 | BLOCKs>. That means: do not even think about calling C<die> without an |
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314 | eval, and do not even think of entering the scheduler in any way. |
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315 | |
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316 | Since both BLOCKs are tied to the current scope, they will automatically |
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317 | be removed when the current scope exits. |
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318 | |
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319 | These functions implement the same concept as C<dynamic-wind> in scheme |
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320 | does, and are useful when you want to localise some resource to a specific |
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321 | coro. |
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322 | |
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323 | They slow down thread switching considerably for coros that use them |
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324 | (about 40% for a BLOCK with a single assignment, so thread switching is |
|
|
325 | still reasonably fast if the handlers are fast). |
|
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326 | |
|
|
327 | These functions are best understood by an example: The following function |
|
|
328 | will change the current timezone to "Antarctica/South_Pole", which |
|
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329 | requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>, |
|
|
330 | which remember/change the current timezone and restore the previous |
|
|
331 | value, respectively, the timezone is only changed for the coro that |
|
|
332 | installed those handlers. |
|
|
333 | |
|
|
334 | use POSIX qw(tzset); |
|
|
335 | |
|
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336 | async { |
|
|
337 | my $old_tz; # store outside TZ value here |
|
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338 | |
|
|
339 | Coro::on_enter { |
|
|
340 | $old_tz = $ENV{TZ}; # remember the old value |
|
|
341 | |
|
|
342 | $ENV{TZ} = "Antarctica/South_Pole"; |
|
|
343 | tzset; # enable new value |
|
|
344 | }; |
|
|
345 | |
|
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346 | Coro::on_leave { |
|
|
347 | $ENV{TZ} = $old_tz; |
|
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348 | tzset; # restore old value |
|
|
349 | }; |
|
|
350 | |
|
|
351 | # at this place, the timezone is Antarctica/South_Pole, |
|
|
352 | # without disturbing the TZ of any other coro. |
|
|
353 | }; |
|
|
354 | |
|
|
355 | This can be used to localise about any resource (locale, uid, current |
|
|
356 | working directory etc.) to a block, despite the existance of other |
|
|
357 | coros. |
|
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358 | |
|
|
359 | Another interesting example implements time-sliced multitasking using |
|
|
360 | interval timers (this could obviously be optimised, but does the job): |
|
|
361 | |
|
|
362 | # "timeslice" the given block |
|
|
363 | sub timeslice(&) { |
|
|
364 | use Time::HiRes (); |
|
|
365 | |
|
|
366 | Coro::on_enter { |
|
|
367 | # on entering the thread, we set an VTALRM handler to cede |
|
|
368 | $SIG{VTALRM} = sub { cede }; |
|
|
369 | # and then start the interval timer |
|
|
370 | Time::HiRes::setitimer &Time::HiRes::ITIMER_VIRTUAL, 0.01, 0.01; |
|
|
371 | }; |
|
|
372 | Coro::on_leave { |
|
|
373 | # on leaving the thread, we stop the interval timer again |
|
|
374 | Time::HiRes::setitimer &Time::HiRes::ITIMER_VIRTUAL, 0, 0; |
|
|
375 | }; |
|
|
376 | |
|
|
377 | &{+shift}; |
|
|
378 | } |
|
|
379 | |
|
|
380 | # use like this: |
|
|
381 | timeslice { |
|
|
382 | # The following is an endless loop that would normally |
|
|
383 | # monopolise the process. Since it runs in a timesliced |
|
|
384 | # environment, it will regularly cede to other threads. |
|
|
385 | while () { } |
|
|
386 | }; |
|
|
387 | |
307 | |
388 | |
308 | =item killall |
389 | =item killall |
309 | |
390 | |
310 | Kills/terminates/cancels all coroutines except the currently running |
391 | Kills/terminates/cancels all coros except the currently running one. |
311 | one. This is useful after a fork, either in the child or the parent, as |
|
|
312 | usually only one of them should inherit the running coroutines. |
|
|
313 | |
392 | |
314 | Note that while this will try to free some of the main programs resources, |
393 | Note that while this will try to free some of the main interpreter |
|
|
394 | resources if the calling coro isn't the main coro, but one |
315 | you cannot free all of them, so if a coroutine that is not the main |
395 | cannot free all of them, so if a coro that is not the main coro |
316 | program calls this function, there will be some one-time resource leak. |
396 | calls this function, there will be some one-time resource leak. |
317 | |
397 | |
318 | =cut |
398 | =cut |
319 | |
399 | |
320 | sub killall { |
400 | sub killall { |
321 | for (Coro::State::list) { |
401 | for (Coro::State::list) { |
… | |
… | |
324 | } |
404 | } |
325 | } |
405 | } |
326 | |
406 | |
327 | =back |
407 | =back |
328 | |
408 | |
329 | =head1 COROUTINE OBJECT METHODS |
409 | =head1 CORO OBJECT METHODS |
330 | |
410 | |
331 | These are the methods you can call on coroutine objects (or to create |
411 | These are the methods you can call on coro objects (or to create |
332 | them). |
412 | them). |
333 | |
413 | |
334 | =over 4 |
414 | =over 4 |
335 | |
415 | |
336 | =item new Coro \&sub [, @args...] |
416 | =item new Coro \&sub [, @args...] |
337 | |
417 | |
338 | Create a new coroutine and return it. When the sub returns, the coroutine |
418 | Create a new coro and return it. When the sub returns, the coro |
339 | automatically terminates as if C<terminate> with the returned values were |
419 | automatically terminates as if C<terminate> with the returned values were |
340 | called. To make the coroutine run you must first put it into the ready |
420 | called. To make the coro run you must first put it into the ready |
341 | queue by calling the ready method. |
421 | queue by calling the ready method. |
342 | |
422 | |
343 | See C<async> and C<Coro::State::new> for additional info about the |
423 | See C<async> and C<Coro::State::new> for additional info about the |
344 | coroutine environment. |
424 | coro environment. |
345 | |
425 | |
346 | =cut |
426 | =cut |
347 | |
427 | |
348 | sub _terminate { |
428 | sub _coro_run { |
349 | terminate &{+shift}; |
429 | terminate &{+shift}; |
350 | } |
430 | } |
351 | |
431 | |
352 | =item $success = $coroutine->ready |
432 | =item $success = $coro->ready |
353 | |
433 | |
354 | Put the given coroutine into the end of its ready queue (there is one |
434 | Put the given coro into the end of its ready queue (there is one |
355 | queue for each priority) and return true. If the coroutine is already in |
435 | queue for each priority) and return true. If the coro is already in |
356 | the ready queue, do nothing and return false. |
436 | the ready queue, do nothing and return false. |
357 | |
437 | |
358 | This ensures that the scheduler will resume this coroutine automatically |
438 | This ensures that the scheduler will resume this coro automatically |
359 | once all the coroutines of higher priority and all coroutines of the same |
439 | once all the coro of higher priority and all coro of the same |
360 | priority that were put into the ready queue earlier have been resumed. |
440 | priority that were put into the ready queue earlier have been resumed. |
361 | |
441 | |
|
|
442 | =item $coro->suspend |
|
|
443 | |
|
|
444 | Suspends the specified coro. A suspended coro works just like any other |
|
|
445 | coro, except that the scheduler will not select a suspended coro for |
|
|
446 | execution. |
|
|
447 | |
|
|
448 | Suspending a coro can be useful when you want to keep the coro from |
|
|
449 | running, but you don't want to destroy it, or when you want to temporarily |
|
|
450 | freeze a coro (e.g. for debugging) to resume it later. |
|
|
451 | |
|
|
452 | A scenario for the former would be to suspend all (other) coros after a |
|
|
453 | fork and keep them alive, so their destructors aren't called, but new |
|
|
454 | coros can be created. |
|
|
455 | |
|
|
456 | =item $coro->resume |
|
|
457 | |
|
|
458 | If the specified coro was suspended, it will be resumed. Note that when |
|
|
459 | the coro was in the ready queue when it was suspended, it might have been |
|
|
460 | unreadied by the scheduler, so an activation might have been lost. |
|
|
461 | |
|
|
462 | To avoid this, it is best to put a suspended coro into the ready queue |
|
|
463 | unconditionally, as every synchronisation mechanism must protect itself |
|
|
464 | against spurious wakeups, and the one in the Coro family certainly do |
|
|
465 | that. |
|
|
466 | |
362 | =item $is_ready = $coroutine->is_ready |
467 | =item $is_ready = $coro->is_ready |
363 | |
468 | |
364 | Return whether the coroutine is currently the ready queue or not, |
469 | Returns true iff the Coro object is in the ready queue. Unless the Coro |
|
|
470 | object gets destroyed, it will eventually be scheduled by the scheduler. |
365 | |
471 | |
|
|
472 | =item $is_running = $coro->is_running |
|
|
473 | |
|
|
474 | Returns true iff the Coro object is currently running. Only one Coro object |
|
|
475 | can ever be in the running state (but it currently is possible to have |
|
|
476 | multiple running Coro::States). |
|
|
477 | |
|
|
478 | =item $is_suspended = $coro->is_suspended |
|
|
479 | |
|
|
480 | Returns true iff this Coro object has been suspended. Suspended Coros will |
|
|
481 | not ever be scheduled. |
|
|
482 | |
366 | =item $coroutine->cancel (arg...) |
483 | =item $coro->cancel (arg...) |
367 | |
484 | |
368 | Terminates the given coroutine and makes it return the given arguments as |
485 | Terminates the given Coro and makes it return the given arguments as |
369 | status (default: the empty list). Never returns if the coroutine is the |
486 | status (default: the empty list). Never returns if the Coro is the |
370 | current coroutine. |
487 | current Coro. |
371 | |
488 | |
372 | =cut |
489 | =cut |
373 | |
490 | |
374 | sub cancel { |
491 | sub cancel { |
375 | my $self = shift; |
492 | my $self = shift; |
376 | |
493 | |
377 | if ($current == $self) { |
494 | if ($current == $self) { |
378 | terminate @_; |
495 | terminate @_; |
379 | } else { |
496 | } else { |
380 | $self->{_status} = [@_]; |
497 | $self->{_status} = [@_]; |
381 | $self->_cancel; |
498 | Coro::State::cancel $self; |
382 | } |
499 | } |
383 | } |
500 | } |
384 | |
501 | |
385 | =item $coroutine->schedule_to |
502 | =item $coro->schedule_to |
386 | |
503 | |
387 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
504 | Puts the current coro to sleep (like C<Coro::schedule>), but instead |
388 | of continuing with the next coro from the ready queue, always switch to |
505 | of continuing with the next coro from the ready queue, always switch to |
389 | the given coroutine object (regardless of priority etc.). The readyness |
506 | the given coro object (regardless of priority etc.). The readyness |
390 | state of that coroutine isn't changed. |
507 | state of that coro isn't changed. |
391 | |
508 | |
392 | This is an advanced method for special cases - I'd love to hear about any |
509 | This is an advanced method for special cases - I'd love to hear about any |
393 | uses for this one. |
510 | uses for this one. |
394 | |
511 | |
395 | =item $coroutine->cede_to |
512 | =item $coro->cede_to |
396 | |
513 | |
397 | Like C<schedule_to>, but puts the current coroutine into the ready |
514 | Like C<schedule_to>, but puts the current coro into the ready |
398 | queue. This has the effect of temporarily switching to the given |
515 | queue. This has the effect of temporarily switching to the given |
399 | coroutine, and continuing some time later. |
516 | coro, and continuing some time later. |
400 | |
517 | |
401 | This is an advanced method for special cases - I'd love to hear about any |
518 | This is an advanced method for special cases - I'd love to hear about any |
402 | uses for this one. |
519 | uses for this one. |
403 | |
520 | |
404 | =item $coroutine->throw ([$scalar]) |
521 | =item $coro->throw ([$scalar]) |
405 | |
522 | |
406 | If C<$throw> is specified and defined, it will be thrown as an exception |
523 | If C<$throw> is specified and defined, it will be thrown as an exception |
407 | inside the coroutine at the next convenient point in time. Otherwise |
524 | inside the coro at the next convenient point in time. Otherwise |
408 | clears the exception object. |
525 | clears the exception object. |
409 | |
526 | |
410 | Coro will check for the exception each time a schedule-like-function |
527 | Coro will check for the exception each time a schedule-like-function |
411 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
528 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
412 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
529 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
… | |
… | |
414 | |
531 | |
415 | The exception object will be thrown "as is" with the specified scalar in |
532 | The exception object will be thrown "as is" with the specified scalar in |
416 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
533 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
417 | (unlike with C<die>). |
534 | (unlike with C<die>). |
418 | |
535 | |
419 | This can be used as a softer means than C<cancel> to ask a coroutine to |
536 | This can be used as a softer means than C<cancel> to ask a coro to |
420 | end itself, although there is no guarantee that the exception will lead to |
537 | end itself, although there is no guarantee that the exception will lead to |
421 | termination, and if the exception isn't caught it might well end the whole |
538 | termination, and if the exception isn't caught it might well end the whole |
422 | program. |
539 | program. |
423 | |
540 | |
424 | You might also think of C<throw> as being the moral equivalent of |
541 | You might also think of C<throw> as being the moral equivalent of |
425 | C<kill>ing a coroutine with a signal (in this case, a scalar). |
542 | C<kill>ing a coro with a signal (in this case, a scalar). |
426 | |
543 | |
427 | =item $coroutine->join |
544 | =item $coro->join |
428 | |
545 | |
429 | Wait until the coroutine terminates and return any values given to the |
546 | Wait until the coro terminates and return any values given to the |
430 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
547 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
431 | from multiple coroutines, and all will be resumed and given the status |
548 | from multiple coro, and all will be resumed and given the status |
432 | return once the C<$coroutine> terminates. |
549 | return once the C<$coro> terminates. |
433 | |
550 | |
434 | =cut |
551 | =cut |
435 | |
552 | |
436 | sub join { |
553 | sub join { |
437 | my $self = shift; |
554 | my $self = shift; |
… | |
… | |
448 | } |
565 | } |
449 | |
566 | |
450 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
567 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
451 | } |
568 | } |
452 | |
569 | |
453 | =item $coroutine->on_destroy (\&cb) |
570 | =item $coro->on_destroy (\&cb) |
454 | |
571 | |
455 | Registers a callback that is called when this coroutine gets destroyed, |
572 | Registers a callback that is called when this coro thread gets destroyed, |
456 | but before it is joined. The callback gets passed the terminate arguments, |
573 | but before it is joined. The callback gets passed the terminate arguments, |
457 | if any, and I<must not> die, under any circumstances. |
574 | if any, and I<must not> die, under any circumstances. |
458 | |
575 | |
|
|
576 | There can be any number of C<on_destroy> callbacks per coro. |
|
|
577 | |
459 | =cut |
578 | =cut |
460 | |
579 | |
461 | sub on_destroy { |
580 | sub on_destroy { |
462 | my ($self, $cb) = @_; |
581 | my ($self, $cb) = @_; |
463 | |
582 | |
464 | push @{ $self->{_on_destroy} }, $cb; |
583 | push @{ $self->{_on_destroy} }, $cb; |
465 | } |
584 | } |
466 | |
585 | |
467 | =item $oldprio = $coroutine->prio ($newprio) |
586 | =item $oldprio = $coro->prio ($newprio) |
468 | |
587 | |
469 | Sets (or gets, if the argument is missing) the priority of the |
588 | Sets (or gets, if the argument is missing) the priority of the |
470 | coroutine. Higher priority coroutines get run before lower priority |
589 | coro thread. Higher priority coro get run before lower priority |
471 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
590 | coros. Priorities are small signed integers (currently -4 .. +3), |
472 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
591 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
473 | to get then): |
592 | to get then): |
474 | |
593 | |
475 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
594 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
476 | 3 > 1 > 0 > -1 > -3 > -4 |
595 | 3 > 1 > 0 > -1 > -3 > -4 |
477 | |
596 | |
478 | # set priority to HIGH |
597 | # set priority to HIGH |
479 | current->prio(PRIO_HIGH); |
598 | current->prio (PRIO_HIGH); |
480 | |
599 | |
481 | The idle coroutine ($Coro::idle) always has a lower priority than any |
600 | The idle coro thread ($Coro::idle) always has a lower priority than any |
482 | existing coroutine. |
601 | existing coro. |
483 | |
602 | |
484 | Changing the priority of the current coroutine will take effect immediately, |
603 | Changing the priority of the current coro will take effect immediately, |
485 | but changing the priority of coroutines in the ready queue (but not |
604 | but changing the priority of a coro in the ready queue (but not running) |
486 | running) will only take effect after the next schedule (of that |
605 | will only take effect after the next schedule (of that coro). This is a |
487 | coroutine). This is a bug that will be fixed in some future version. |
606 | bug that will be fixed in some future version. |
488 | |
607 | |
489 | =item $newprio = $coroutine->nice ($change) |
608 | =item $newprio = $coro->nice ($change) |
490 | |
609 | |
491 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
610 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
492 | higher values mean lower priority, just as in unix). |
611 | higher values mean lower priority, just as in UNIX's nice command). |
493 | |
612 | |
494 | =item $olddesc = $coroutine->desc ($newdesc) |
613 | =item $olddesc = $coro->desc ($newdesc) |
495 | |
614 | |
496 | Sets (or gets in case the argument is missing) the description for this |
615 | Sets (or gets in case the argument is missing) the description for this |
497 | coroutine. This is just a free-form string you can associate with a |
616 | coro thread. This is just a free-form string you can associate with a |
498 | coroutine. |
617 | coro. |
499 | |
618 | |
500 | This method simply sets the C<< $coroutine->{desc} >> member to the given |
619 | This method simply sets the C<< $coro->{desc} >> member to the given |
501 | string. You can modify this member directly if you wish. |
620 | string. You can modify this member directly if you wish, and in fact, this |
|
|
621 | is often preferred to indicate major processing states that cna then be |
|
|
622 | seen for example in a L<Coro::Debug> session: |
|
|
623 | |
|
|
624 | sub my_long_function { |
|
|
625 | local $Coro::current->{desc} = "now in my_long_function"; |
|
|
626 | ... |
|
|
627 | $Coro::current->{desc} = "my_long_function: phase 1"; |
|
|
628 | ... |
|
|
629 | $Coro::current->{desc} = "my_long_function: phase 2"; |
|
|
630 | ... |
|
|
631 | } |
502 | |
632 | |
503 | =cut |
633 | =cut |
504 | |
634 | |
505 | sub desc { |
635 | sub desc { |
506 | my $old = $_[0]{desc}; |
636 | my $old = $_[0]{desc}; |
… | |
… | |
519 | |
649 | |
520 | =over 4 |
650 | =over 4 |
521 | |
651 | |
522 | =item Coro::nready |
652 | =item Coro::nready |
523 | |
653 | |
524 | Returns the number of coroutines that are currently in the ready state, |
654 | Returns the number of coro that are currently in the ready state, |
525 | i.e. that can be switched to by calling C<schedule> directory or |
655 | i.e. that can be switched to by calling C<schedule> directory or |
526 | indirectly. The value C<0> means that the only runnable coroutine is the |
656 | indirectly. The value C<0> means that the only runnable coro is the |
527 | currently running one, so C<cede> would have no effect, and C<schedule> |
657 | currently running one, so C<cede> would have no effect, and C<schedule> |
528 | would cause a deadlock unless there is an idle handler that wakes up some |
658 | would cause a deadlock unless there is an idle handler that wakes up some |
529 | coroutines. |
659 | coro. |
530 | |
660 | |
531 | =item my $guard = Coro::guard { ... } |
661 | =item my $guard = Coro::guard { ... } |
532 | |
662 | |
533 | This creates and returns a guard object. Nothing happens until the object |
663 | This function still exists, but is deprecated. Please use the |
534 | gets destroyed, in which case the codeblock given as argument will be |
664 | C<Guard::guard> function instead. |
535 | executed. This is useful to free locks or other resources in case of a |
|
|
536 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
537 | guard block will be executed. The guard object supports only one method, |
|
|
538 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
539 | |
665 | |
540 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
541 | or the function returns: |
|
|
542 | |
|
|
543 | sub do_something { |
|
|
544 | my $guard = Coro::guard { $busy = 0 }; |
|
|
545 | $busy = 1; |
|
|
546 | |
|
|
547 | # do something that requires $busy to be true |
|
|
548 | } |
|
|
549 | |
|
|
550 | =cut |
666 | =cut |
551 | |
667 | |
552 | sub guard(&) { |
668 | BEGIN { *guard = \&Guard::guard } |
553 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
554 | } |
|
|
555 | |
|
|
556 | sub Coro::guard::cancel { |
|
|
557 | ${$_[0]} = sub { }; |
|
|
558 | } |
|
|
559 | |
|
|
560 | sub Coro::guard::DESTROY { |
|
|
561 | ${$_[0]}->(); |
|
|
562 | } |
|
|
563 | |
|
|
564 | |
669 | |
565 | =item unblock_sub { ... } |
670 | =item unblock_sub { ... } |
566 | |
671 | |
567 | This utility function takes a BLOCK or code reference and "unblocks" it, |
672 | This utility function takes a BLOCK or code reference and "unblocks" it, |
568 | returning a new coderef. Unblocking means that calling the new coderef |
673 | returning a new coderef. Unblocking means that calling the new coderef |
569 | will return immediately without blocking, returning nothing, while the |
674 | will return immediately without blocking, returning nothing, while the |
570 | original code ref will be called (with parameters) from within another |
675 | original code ref will be called (with parameters) from within another |
571 | coroutine. |
676 | coro. |
572 | |
677 | |
573 | The reason this function exists is that many event libraries (such as the |
678 | The reason this function exists is that many event libraries (such as |
574 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
679 | the venerable L<Event|Event> module) are not thread-safe (a weaker form |
575 | of thread-safety). This means you must not block within event callbacks, |
680 | of reentrancy). This means you must not block within event callbacks, |
576 | otherwise you might suffer from crashes or worse. The only event library |
681 | otherwise you might suffer from crashes or worse. The only event library |
577 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
682 | currently known that is safe to use without C<unblock_sub> is L<EV> (but |
|
|
683 | you might still run into deadlocks if all event loops are blocked). |
|
|
684 | |
|
|
685 | Coro will try to catch you when you block in the event loop |
|
|
686 | ("FATAL:$Coro::IDLE blocked itself"), but this is just best effort and |
|
|
687 | only works when you do not run your own event loop. |
578 | |
688 | |
579 | This function allows your callbacks to block by executing them in another |
689 | This function allows your callbacks to block by executing them in another |
580 | coroutine where it is safe to block. One example where blocking is handy |
690 | coro where it is safe to block. One example where blocking is handy |
581 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
691 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
582 | disk, for example. |
692 | disk, for example. |
583 | |
693 | |
584 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
694 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
585 | creating event callbacks that want to block. |
695 | creating event callbacks that want to block. |
586 | |
696 | |
587 | If your handler does not plan to block (e.g. simply sends a message to |
697 | If your handler does not plan to block (e.g. simply sends a message to |
588 | another coroutine, or puts some other coroutine into the ready queue), |
698 | another coro, or puts some other coro into the ready queue), there is |
589 | there is no reason to use C<unblock_sub>. |
699 | no reason to use C<unblock_sub>. |
590 | |
700 | |
591 | Note that you also need to use C<unblock_sub> for any other callbacks that |
701 | Note that you also need to use C<unblock_sub> for any other callbacks that |
592 | are indirectly executed by any C-based event loop. For example, when you |
702 | are indirectly executed by any C-based event loop. For example, when you |
593 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
703 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
594 | provides callbacks that are the result of some event callback, then you |
704 | provides callbacks that are the result of some event callback, then you |
… | |
… | |
624 | unshift @unblock_queue, [$cb, @_]; |
734 | unshift @unblock_queue, [$cb, @_]; |
625 | $unblock_scheduler->ready; |
735 | $unblock_scheduler->ready; |
626 | } |
736 | } |
627 | } |
737 | } |
628 | |
738 | |
629 | =item $cb = Coro::rouse_cb |
739 | =item $cb = rouse_cb |
630 | |
740 | |
631 | Create and return a "rouse callback". That's a code reference that, when |
741 | Create and return a "rouse callback". That's a code reference that, |
632 | called, will save its arguments and notify the owner coroutine of the |
742 | when called, will remember a copy of its arguments and notify the owner |
633 | callback. |
743 | coro of the callback. |
634 | |
744 | |
635 | See the next function. |
745 | See the next function. |
636 | |
746 | |
637 | =item @args = Coro::rouse_wait [$cb] |
747 | =item @args = rouse_wait [$cb] |
638 | |
748 | |
639 | Wait for the specified rouse callback (or the last one tht was created in |
749 | Wait for the specified rouse callback (or the last one that was created in |
640 | this coroutine). |
750 | this coro). |
641 | |
751 | |
642 | As soon as the callback is invoked (or when the calback was invoked before |
752 | As soon as the callback is invoked (or when the callback was invoked |
643 | C<rouse_wait>), it will return a copy of the arguments originally passed |
753 | before C<rouse_wait>), it will return the arguments originally passed to |
644 | to the rouse callback. |
754 | the rouse callback. In scalar context, that means you get the I<last> |
|
|
755 | argument, just as if C<rouse_wait> had a C<return ($a1, $a2, $a3...)> |
|
|
756 | statement at the end. |
645 | |
757 | |
646 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
758 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
647 | |
759 | |
648 | =back |
760 | =back |
649 | |
761 | |
650 | =cut |
762 | =cut |
651 | |
763 | |
|
|
764 | for my $module (qw(Channel RWLock Semaphore SemaphoreSet Signal Specific)) { |
|
|
765 | my $old = defined &{"Coro::$module\::new"} && \&{"Coro::$module\::new"}; |
|
|
766 | |
|
|
767 | *{"Coro::$module\::new"} = sub { |
|
|
768 | require "Coro/$module.pm"; |
|
|
769 | |
|
|
770 | # some modules have their new predefined in State.xs, some don't |
|
|
771 | *{"Coro::$module\::new"} = $old |
|
|
772 | if $old; |
|
|
773 | |
|
|
774 | goto &{"Coro::$module\::new"}; |
|
|
775 | }; |
|
|
776 | } |
|
|
777 | |
652 | 1; |
778 | 1; |
653 | |
779 | |
654 | =head1 HOW TO WAIT FOR A CALLBACK |
780 | =head1 HOW TO WAIT FOR A CALLBACK |
655 | |
781 | |
656 | It is very common for a coroutine to wait for some callback to be |
782 | It is very common for a coro to wait for some callback to be |
657 | called. This occurs naturally when you use coroutines in an otherwise |
783 | called. This occurs naturally when you use coro in an otherwise |
658 | event-based program, or when you use event-based libraries. |
784 | event-based program, or when you use event-based libraries. |
659 | |
785 | |
660 | These typically register a callback for some event, and call that callback |
786 | These typically register a callback for some event, and call that callback |
661 | when the event occured. In a coroutine, however, you typically want to |
787 | when the event occured. In a coro, however, you typically want to |
662 | just wait for the event, simplyifying things. |
788 | just wait for the event, simplyifying things. |
663 | |
789 | |
664 | For example C<< AnyEvent->child >> registers a callback to be called when |
790 | For example C<< AnyEvent->child >> registers a callback to be called when |
665 | a specific child has exited: |
791 | a specific child has exited: |
666 | |
792 | |
667 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
793 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
668 | |
794 | |
669 | But from withina coroutine, you often just want to write this: |
795 | But from within a coro, you often just want to write this: |
670 | |
796 | |
671 | my $status = wait_for_child $pid; |
797 | my $status = wait_for_child $pid; |
672 | |
798 | |
673 | Coro offers two functions specifically designed to make this easy, |
799 | Coro offers two functions specifically designed to make this easy, |
674 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
800 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
675 | |
801 | |
676 | The first function, C<rouse_cb>, generates and returns a callback that, |
802 | The first function, C<rouse_cb>, generates and returns a callback that, |
677 | when invoked, will save it's arguments and notify the coroutine that |
803 | when invoked, will save its arguments and notify the coro that |
678 | created the callback. |
804 | created the callback. |
679 | |
805 | |
680 | The second function, C<rouse_wait>, waits for the callback to be called |
806 | The second function, C<rouse_wait>, waits for the callback to be called |
681 | (by calling C<schedule> to go to sleep) and returns the arguments |
807 | (by calling C<schedule> to go to sleep) and returns the arguments |
682 | originally passed to the callback. |
808 | originally passed to the callback. |
… | |
… | |
697 | you can roll your own, using C<schedule>: |
823 | you can roll your own, using C<schedule>: |
698 | |
824 | |
699 | sub wait_for_child($) { |
825 | sub wait_for_child($) { |
700 | my ($pid) = @_; |
826 | my ($pid) = @_; |
701 | |
827 | |
702 | # store the current coroutine in $current, |
828 | # store the current coro in $current, |
703 | # and provide result variables for the closure passed to ->child |
829 | # and provide result variables for the closure passed to ->child |
704 | my $current = $Coro::current; |
830 | my $current = $Coro::current; |
705 | my ($done, $rstatus); |
831 | my ($done, $rstatus); |
706 | |
832 | |
707 | # pass a closure to ->child |
833 | # pass a closure to ->child |
… | |
… | |
723 | |
849 | |
724 | =item fork with pthread backend |
850 | =item fork with pthread backend |
725 | |
851 | |
726 | When Coro is compiled using the pthread backend (which isn't recommended |
852 | When Coro is compiled using the pthread backend (which isn't recommended |
727 | but required on many BSDs as their libcs are completely broken), then |
853 | but required on many BSDs as their libcs are completely broken), then |
728 | coroutines will not survive a fork. There is no known workaround except to |
854 | coro will not survive a fork. There is no known workaround except to |
729 | fix your libc and use a saner backend. |
855 | fix your libc and use a saner backend. |
730 | |
856 | |
731 | =item perl process emulation ("threads") |
857 | =item perl process emulation ("threads") |
732 | |
858 | |
733 | This module is not perl-pseudo-thread-safe. You should only ever use this |
859 | This module is not perl-pseudo-thread-safe. You should only ever use this |
734 | module from the same thread (this requirement might be removed in the |
860 | module from the first thread (this requirement might be removed in the |
735 | future to allow per-thread schedulers, but Coro::State does not yet allow |
861 | future to allow per-thread schedulers, but Coro::State does not yet allow |
736 | this). I recommend disabling thread support and using processes, as having |
862 | this). I recommend disabling thread support and using processes, as having |
737 | the windows process emulation enabled under unix roughly halves perl |
863 | the windows process emulation enabled under unix roughly halves perl |
738 | performance, even when not used. |
864 | performance, even when not used. |
739 | |
865 | |
740 | =item coroutine switching not signal safe |
866 | =item coro switching is not signal safe |
741 | |
867 | |
742 | You must not switch to another coroutine from within a signal handler |
868 | You must not switch to another coro from within a signal handler (only |
743 | (only relevant with %SIG - most event libraries provide safe signals). |
869 | relevant with %SIG - most event libraries provide safe signals), I<unless> |
|
|
870 | you are sure you are not interrupting a Coro function. |
744 | |
871 | |
745 | That means you I<MUST NOT> call any function that might "block" the |
872 | That means you I<MUST NOT> call any function that might "block" the |
746 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
873 | current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
747 | anything that calls those. Everything else, including calling C<ready>, |
874 | anything that calls those. Everything else, including calling C<ready>, |
748 | works. |
875 | works. |
749 | |
876 | |
750 | =back |
877 | =back |
751 | |
878 | |
752 | |
879 | |
|
|
880 | =head1 WINDOWS PROCESS EMULATION |
|
|
881 | |
|
|
882 | A great many people seem to be confused about ithreads (for example, Chip |
|
|
883 | Salzenberg called me unintelligent, incapable, stupid and gullible, |
|
|
884 | while in the same mail making rather confused statements about perl |
|
|
885 | ithreads (for example, that memory or files would be shared), showing his |
|
|
886 | lack of understanding of this area - if it is hard to understand for Chip, |
|
|
887 | it is probably not obvious to everybody). |
|
|
888 | |
|
|
889 | What follows is an ultra-condensed version of my talk about threads in |
|
|
890 | scripting languages given on the perl workshop 2009: |
|
|
891 | |
|
|
892 | The so-called "ithreads" were originally implemented for two reasons: |
|
|
893 | first, to (badly) emulate unix processes on native win32 perls, and |
|
|
894 | secondly, to replace the older, real thread model ("5.005-threads"). |
|
|
895 | |
|
|
896 | It does that by using threads instead of OS processes. The difference |
|
|
897 | between processes and threads is that threads share memory (and other |
|
|
898 | state, such as files) between threads within a single process, while |
|
|
899 | processes do not share anything (at least not semantically). That |
|
|
900 | means that modifications done by one thread are seen by others, while |
|
|
901 | modifications by one process are not seen by other processes. |
|
|
902 | |
|
|
903 | The "ithreads" work exactly like that: when creating a new ithreads |
|
|
904 | process, all state is copied (memory is copied physically, files and code |
|
|
905 | is copied logically). Afterwards, it isolates all modifications. On UNIX, |
|
|
906 | the same behaviour can be achieved by using operating system processes, |
|
|
907 | except that UNIX typically uses hardware built into the system to do this |
|
|
908 | efficiently, while the windows process emulation emulates this hardware in |
|
|
909 | software (rather efficiently, but of course it is still much slower than |
|
|
910 | dedicated hardware). |
|
|
911 | |
|
|
912 | As mentioned before, loading code, modifying code, modifying data |
|
|
913 | structures and so on is only visible in the ithreads process doing the |
|
|
914 | modification, not in other ithread processes within the same OS process. |
|
|
915 | |
|
|
916 | This is why "ithreads" do not implement threads for perl at all, only |
|
|
917 | processes. What makes it so bad is that on non-windows platforms, you can |
|
|
918 | actually take advantage of custom hardware for this purpose (as evidenced |
|
|
919 | by the forks module, which gives you the (i-) threads API, just much |
|
|
920 | faster). |
|
|
921 | |
|
|
922 | Sharing data is in the i-threads model is done by transfering data |
|
|
923 | structures between threads using copying semantics, which is very slow - |
|
|
924 | shared data simply does not exist. Benchmarks using i-threads which are |
|
|
925 | communication-intensive show extremely bad behaviour with i-threads (in |
|
|
926 | fact, so bad that Coro, which cannot take direct advantage of multiple |
|
|
927 | CPUs, is often orders of magnitude faster because it shares data using |
|
|
928 | real threads, refer to my talk for details). |
|
|
929 | |
|
|
930 | As summary, i-threads *use* threads to implement processes, while |
|
|
931 | the compatible forks module *uses* processes to emulate, uhm, |
|
|
932 | processes. I-threads slow down every perl program when enabled, and |
|
|
933 | outside of windows, serve no (or little) practical purpose, but |
|
|
934 | disadvantages every single-threaded Perl program. |
|
|
935 | |
|
|
936 | This is the reason that I try to avoid the name "ithreads", as it is |
|
|
937 | misleading as it implies that it implements some kind of thread model for |
|
|
938 | perl, and prefer the name "windows process emulation", which describes the |
|
|
939 | actual use and behaviour of it much better. |
|
|
940 | |
753 | =head1 SEE ALSO |
941 | =head1 SEE ALSO |
754 | |
942 | |
755 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
943 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
756 | |
944 | |
757 | Debugging: L<Coro::Debug>. |
945 | Debugging: L<Coro::Debug>. |
758 | |
946 | |
759 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
947 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
760 | |
948 | |
761 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
949 | Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
762 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
950 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
763 | |
951 | |
764 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
952 | I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
765 | |
953 | |
766 | Compatibility: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
954 | Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
767 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
955 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
768 | L<Coro::Select>. |
956 | L<Coro::Select>. |
769 | |
957 | |
770 | XS API: L<Coro::MakeMaker>. |
958 | XS API: L<Coro::MakeMaker>. |
771 | |
959 | |
772 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
960 | Low level Configuration, Thread Environment, Continuations: L<Coro::State>. |
773 | |
961 | |
774 | =head1 AUTHOR |
962 | =head1 AUTHOR |
775 | |
963 | |
776 | Marc Lehmann <schmorp@schmorp.de> |
964 | Marc Lehmann <schmorp@schmorp.de> |
777 | http://home.schmorp.de/ |
965 | http://home.schmorp.de/ |