On Tue, May 5, 2020 at 6:44 PM Joseph Jenne via Python-Dev <python-dev@python.org> wrote:
I'm seeing a drop in performance of both multiprocess and subinterpreter based runs in the 8-CPU case, where performance drops by about half despite having enough logical CPUs, while the other cases scale quite well. Is there some issue with python multiprocessing/subinterpreters on the same logical core?
This is not a Python issue at all, but a limitation of logical cores. The logical cores still share the same physical resources, so the logical cores are contending for the same execution resources. Actually it would probably be bad if Python *didn't* scale this way, because that would indicate that a Python process that should be running full-blast isn't actually utilizing all the physical resources of a CPU! -Cody