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Revision 1.2 by root, Tue Jun 30 01:01:34 2015 UTC vs.
Revision 1.3 by root, Wed Jul 1 22:53:37 2015 UTC

… …
7 7
8 # or, if you want it disabled by default (e.g. to use it from a module) 8 # or, if you want it disabled by default (e.g. to use it from a module)
9 use Coro::Multicore (); 9 use Coro::Multicore ();
10 10
11DESCRIPTION 11DESCRIPTION
12 EXPERIMENTAL WARNING: This module is in its early stages of development.
13 It's fine to try out, but it didn't receive the normal amount of testing
14 and real-world usage that my other modules have gone through.
15
12 While Coro threads (unlike ithreads) provide real threads similar to 16 While Coro threads (unlike ithreads) provide real threads similar to
13 pthreads, python threads and so on, they do not run in parallel to each 17 pthreads, python threads and so on, they do not run in parallel to each
14 other even on machines with multiple CPUs or multiple CPU cores. 18 other even on machines with multiple CPUs or multiple CPU cores.
15 19
16 This module lifts this restriction under two very specific but useful 20 This module lifts this restriction under two very specific but useful
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86 Coro::Multicore::scoped_disable 90 Coro::Multicore::scoped_disable
87 The opposite of "Coro::Multicore::scope_disable": instructs 91 The opposite of "Coro::Multicore::scope_disable": instructs
88 Coro::Multicore to *not* handle the next multicore-enabled request. 92 Coro::Multicore to *not* handle the next multicore-enabled request.
89 93
90INTERACTION WITH OTHER SOFTWARE 94INTERACTION WITH OTHER SOFTWARE
91 TODO 95 This module is very similar to other environments where perl
96 interpreters are moved between threads, such as mod_perl2, and the same
97 caveats apply.
98
99 I want to spell out the most important ones:
100
101 pthreads usage
102 Any creation of pthreads make it impossible to fork portably from a
103 perl program, as forking from within a threaded program will leave
104 the program in a state similar to a signal handler. While it might
105 work on some platforms (as an extension), this might also result in
106 silent data corruption. It also seems to work most of the time, so
107 it's hard to test for this.
108
109 I recommend using something like AnyEvent::Fork, which can create
110 subprocesses safely (via Proc::FastSpawn).
111
112 Similar issues exist for signal handlers, although this module works
113 hard to keep safe perl signals safe.
114
115 module support
116 This module moves the same perl interpreter between different
117 threads. Some modules might get confused by that (although this can
118 usually be considered a bug). This is a rare case though.
119
120 event loop reliance
121 To be able to wake up programs waiting for results, this module
122 relies on an active event loop (via AnyEvent). This is used to
123 notify the perl interpreter when the asynchronous task is done.
124
125 Since event loops typically fail to work properly after a fork, this
126 means that some operations that were formerly working will now hang
127 after fork.
128
129 A workaround is to call "Coro::Multicore::enable 0" after a fork to
130 disable the module.
131
132 Future versions of this module might do this automatically.
92 133
93BUGS 134BUGS
94 (OS-) threads are never released 135 (OS-) threads are never released
95 At the moment, threads that were created once will never be freed. 136 At the moment, threads that were created once will never be freed.
96 They will be reused for asynchronous requests, though, so a slong as 137 They will be reused for asynchronous requests, though, so a slong as
97 you limit the maximum number of concurrent asynchronous tasks, this 138 you limit the maximum number of concurrent asynchronous tasks, this
98 will also limit the maximum number of threads created. 139 will also limit the maximum number of threads created.
99 140
100 Future versions will likely lift this limitation. 141 Future versions will likely lift this limitation.
101 142
102 AnyEvent is initalised on module load 143 AnyEvent is initalised at module load time
103 AnyEvent is initialised on module load, as opposed to at a later 144 AnyEvent is initialised on module load, as opposed to at a later
104 time. 145 time.
105 146
106 Future versions will likely change this. 147 Future versions will likely change this.
107 148

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