On 19 juin, 19:13, s...@pobox.com wrote: > Olivier> what do you mean ? > > Olivier> Cpython can't benefit from multi-core without multiple > Olivier> processes. > > It can, precisely as Martin indicated. Only one thread at a time can hold > the GIL. That doesn't mean that multiple threads can't execute. Suppose
I don't say multiple threads can't execute....(?). I say that with the Python library, I don't see (yet) benefit with multiple threads *on* multiple CPU/core. Ever seen this recent video/presentation ? : http://blip.tv/file/2232410 http://www.dabeaz.com/python/GIL.pdf > you have two threads, one of which winds up executing some bit of C code > which doesn't mess with the Python run-time at all (say, a matrix multiply). I don't know how to do that with common Python operations... Only one thread will be really running at a time in memory (meanwhile other thread are waiting). Are you refering to a specialized code ? > Before launching into the matrix multiply, the extension module releases the > GIL then performs the multiply. With the GIL released another thread can > acquire it. Once the multiply finishes the first thread needs to reacquire > the GIL before executing any calls into the Python runtime or returning. I don't see such improvement in the Python library, or maybe you can indicate us some meaningfull example...? I currently only use CPython, with PIL, Reportlab...etc. I don't see improvement on a Core2duo CPU and Python. How to proceed (following what you wrote) ? A contrario, I saw *real* improvement on parallel computing with the Py 2.6 multiprocessing module. Olivier -- http://mail.python.org/mailman/listinfo/python-list
