Do Docker containers share a single Python GIL?

Question

When I run a Python script inside a Docker container, it completes one execution loop in ~1 minute. Now as I spin up 2 more containers from same image, and run Python scripts inside them, everything slow down to a crawl and start requiring 5-6 minutes per loop.

None of the scripts are resource bound; there is plenty of RAM and CPU cores sitting around idle. This happens when running 3 containers on a 64-core Xeon Phi system.

So does Docker share a common Python GIL lock among all containers? What are my options to separate the GILs, so each process will run at its full potential speed?

Thank you!

Answer 1

So does Docker share a common Python GIL lock among all containers?

NO.

The GIL is per Python process, a Docker container may have 1 or many Python processes, each with it's own GIL.

If you are not multi-threading, you should not even be aware of the GIL. Are you using threads at all?