stress.py uses multiprocessing if it is present, circumventing the GIL; we ran the tests with python 2.6.5.
David Schoonover On Jul 19, 2010, at 1:51 PM, Peter Schuller wrote: >>> One with 50 threads; it is remote from the cluster but within the same >>> DC in both cases. I also run the test with multiple clients and saw >>> similar results when summing the reqs/sec. >> >> Multiple client processes, or multiple client machines? > > In particular, note that the way CPython works, if you're CPU bound > across many threads, you're constantly hitting the worst possible > scenario with respect to wasting CPU cycles on multiple cores (due to > the extremely contended GIL). While I'd still expect to see an > increase in throughput from running multiple separate processes on the > same (multi-core) machine, I really wouldn't be too sure. Even with > supposedly idle CPU you may still be bottlenecking on the client > depending on scheduling decisions in the kernel. > > -- > / Peter Schuller
