On 09.02.2012 20:05, Guido van Rossum wrote: > I'm curious about the module loader problem. Did someone ever analyze > the cause and come up with a fix? Is it the import lock? Maybe it's > something for the bug tracker. See this: http://mail.scipy.org/pipermail/numpy-discussion/2012-January/059801.html The offender is actually imp.find_module, which results in huge number of failed open() calls when used concurrently from many processes. So a solution is to have one process locate the modules and then broadcast their location to the other processes. There is even a paper on the issue. Here they suggest importing from ramdisk might work on IBM blue gene, but not on Cray. http://www.cs.uoregon.edu/Research/paracomp/papers/iccs11/iccs_paper_final.pdf Another solution might be to use sys.meta_path to bypass imp.find_module: http://mail.scipy.org/pipermail/numpy-discussion/2012-January/059813.html The best solution would of course be to fix imp.find_module so it scales properly. Sturla