[pypy-issue] [issue1644] FreeBSD: test_multiprocessing hangs

[Tobias Oberstein]

Tobias Oberstein <tobias.oberstein at gmail.com> added the comment:

This _might_ be related to Posix semaphores (whcih apparently are used by the
multiprocessing module and hence the tests) on FreeBSD. Probably max number,
probably anyonymous shared (in SHM), probably named shared cross-process. I'm
not sure. I dump a couple of infos here for reference:

http://bugs.python.org/issue10348

"sysctl p1003_1b.sem_nsems_max" gives the maximum number of POSIX semaphores
(per process? system wide?).

Since FreeBSD 8.1, "sudo sysctl -w p1003_1b.sem_nsems_max=256" can be used to
change this limit at runtime.

http://www.freebsd.org/cgi/man.cgi?query=sem_init&apropos=0&sektion=0&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html
http://www.freebsd.org/cgi/man.cgi?query=sem_open&apropos=0&sektion=0&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html

==

p1003_1b.sem_nsems_max is currently set to 0 on the FreeBSD buildslave. I don't
know what that means: a) unlimited, b) kernel source default max? I don't think
it literally means 0.

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