On Mar 2, 12:59 pm, Tim Arnold <a_j...@bellsouth.net> wrote: > On Mar 2, 11:52 am, Philip Semanchuk <phi...@semanchuk.com> wrote: > > On Mar 2, 2010, at 11:31 AM, Tim Arnold wrote: > > > > Hi, > > > I'm intending to use multiprocessing on a freebsd machine (6.3 > > > release, quad core, 8cpus, amd64). I see in the doc that on this > > > platform I can't use synchronize: > > > > ImportError: This platform lacks a functioning sem_open > > > implementation, therefore, the required synchronization primitives > > > needed will not function, see issue 3770. > > > > As far as I can tell, I have no need to synchronize the processes--I > > > have several processes run separately and I need to know when they're > > > all finished; there's no communication between them and each owns its > > > own log file for output. > > > > Is anyone using multiprocessing on FreeBSD and run into any other > > > gotchas? > > > Hi Tim, > > I don't use multiprocessing but I've written two low-level IPC > > packages, one for SysV IPC and the other for POSIX IPC. > > > I think that multiprocessing prefers POSIX IPC (which is where > > sem_open() comes from). I don't know what it uses if that's not > > available, but SysV IPC seems a likely alternative. I must emphasize, > > however, that that's a guess on my part. > > > FreeBSD didn't have POSIX IPC support until 7.0, and that was sort of > > broken until 7.2. As it happens, I was testing my POSIX IPC code > > against 7.2 last night and it works just fine. > > > SysV IPC works under FreeBSD 6 (and perhaps earlier versions; 6 is the > > oldest I've tested). ISTR that by default each message queue is > > limited to 2048 bytes in total size. 'sysctl kern.ipc' can probably > > tell you that and may even let you change it. Other than that I can't > > think of any SysV limitations that might bite you. > > > HTH > > Philip > > Hi Philip, > Thanks for that information. I wish I could upgrade the machine to > 7.2! alas, out of my power. I get the following results from sysctl: > % sysctl kern.ipc | grep msg > kern.ipc.msgseg: 2048 > kern.ipc.msgssz: 8 > kern.ipc.msgtql: 40 > kern.ipc.msgmnb: 2048 > kern.ipc.msgmni: 40 > kern.ipc.msgmax: 16384 > > I'll write some test programs using multiprocessing and see how they > go before committing to rewrite my current code. I've also been > looking at 'parallel python' although it may have the same > issues.http://www.parallelpython.com/ > > thanks again, > --Tim
Well that didn't work out well. I can't import either Queue or Pool from multiprocessing, so I'm back to the drawing board. I'll see now how parallel python does on freebsd. --Tim -- http://mail.python.org/mailman/listinfo/python-list
