On Dec 29, 2010, at 8:17 AM, Victor Stinner wrote: > Hi, > > FreeBSD 7.2 3.x buildbot is red since some weeks (or months?) because of > a concurrent.futures failure. The problem is that > test_concurrent_futures uses many (multiprocessing) POSIX semaphores, > whereas POSIX semaphores support in FreeBSD is recent and limited. We > have to use SysV semaphores (ftok, semget, semop, semctl, ...) instead > of POSIX semaphores (sem_open, sem_getvalue, sem_unlink, ...). See: > > * http://bugs.python.org/issue10348 > * "Too many open files" errors on "x86 FreeBSD 7.2 3.x" buildbot > ^-- thread in python-dev opened last month > > I would like to know if it should be considered as a release blocker. > Georg Brandl said yes on IRC. Does anyone know SysV API? I tried to > write a patch, but I never used semaphores (POSIX or SysV). > > There is a third party module which looks complete and stable: > http://semanchuk.com/philip/sysv_ipc/ > > It is released under the BSD license. It supports semaphores, but also > shared memory and message queues. We don't need all of those, semaphores > would be enough. I added its author (Philip Semanchuk) to this thread.
Hi all, What Victor says above is correct, although I wasn't aware that POSIX IPC under FreeBSD 7.2 was still having problems. Prior to 7.2 it was broken but 7.2 worked OK in my limited testing. In any case, the sysv_ipc module is mine and it's mature and you're welcome to pillage it in whole or in part. > I don't know how we should decide to use POSIX or SysV semaphores. It > looks like SysV is preferred on FreeBSD and Darwin (and maybe all BSD > based OSes), and POSIX is preferred on Linux. Hmmm, "preferred" is a tricky word here. I would phrase it slightly differently: POSIX IPC is preferred everywhere (by me, at least) because it's a more modern API. However, SysV IPC is fully supported everywhere while the same can't be said about POSIX IPC. Speaking of POSIX IPC, I also have a posix_ipc module that's quite similar to sysv_ipc and the platform notes in the documentation tell one what support to expect for POSIX IPC under various platforms: http://semanchuk.com/philip/posix_ipc/#platforms Cheers Philip _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
