You're all right. The Python interpreter can't multiprocess, but Python threads are true operating system threads. So all you need to do is call down from Python into C or some other language, free up the global interpreter lock, and presto, you get *real* multiprocessing without every having to write a single line of platform-specific threading code.
Virtually every API call in PyMOL goes through this cycle, which means that PyMOL rendering is indeed much faster on multi-cpu systems. Also, multithreaded Python programs (such as GUIs) can run concurrently with PyMOL in the same process on multi-cpu systems. The best speed-up I've seen so far was on a 12-cpu Altix with 12 threads, where PyMOL rendering was about 9X faster. Of course, for the money, you should just by a Linux cluster and split your multi-frame rendering job over many dual-CPU nodes. Cheers, Warren -- Warren L. DeLano, Ph.D. Principal Scientist . DeLano Scientific LLC . 400 Oyster Point Blvd., Suite 213 . South San Francisco, CA 94080 . Biz:(650)-872-0942 Tech:(650)-872-0834 . Fax:(650)-872-0273 Cell:(650)-346-1154 . mailto:war...@delsci.com > -----Original Message----- > From: pymol-users-ad...@lists.sourceforge.net > [mailto:pymol-users-ad...@lists.sourceforge.net] On Behalf Of > Kristoffer Winther Sørensen > Sent: Wednesday, April 20, 2005 4:49 AM > To: Serge Cohen > Cc: EPF (Esben Peter Friis); Neil Ranson; > PyMOL-users@lists.sourceforge.net > Subject: Re: [PyMOL] multi cpu rendering > > Dear Serge, > > I suggest you simply make a test. > > > Indeed if you read the documentation of Python, you'll see that the > > python byte-code interpreter is not able to run multiple > thread at any > > given time > > I don't think the PyMOL raytracer is written in Python. > Furtermore, when I raytrace in PyMOL on my dual CPU Athlon MP > both CPU's are utilized (top shows 93% under linux). So it > does multithread. > > Regards, > > ./ Kristoffer > > > > > > ------------------------------------------------------- > This SF.Net email is sponsored by: New Crystal Reports XI. > Version 11 adds new functionality designed to reduce time > involved in creating, integrating, and deploying reporting > solutions. Free runtime info, new features, or free trial, > at: http://www.businessobjects.com/devxi/728 > _______________________________________________ > PyMOL-users mailing list > PyMOL-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/pymol-users >
