Gilectomy is Larry Hastings’s project to attempt to remove the GIL from CPython. It a fork on CPython which uses lock per object rather than using a Global Interpreter Lock (GIL).

Gilectomy has multiple issues, but the two main issues are:

  • The current C API: “CPython doesn’t use multiple cores and Gilectomy 1.0 is not high performance, which leads him to consider breaking the C API”.

  • Reference counting: “With his complicated buffered-reference-count approach he was able to get his “gilectomized” interpreter to reach performance parity with CPython—except that his interpreter was running on around seven cores to keep up with CPython on one.”

For “Gilectomy 2.0”, Hastings will be looking at using a tracing garbage collector (GC), rather than the CPython GC that is based on reference counts. Tracing GCs are more multi-core friendly, but he doesn’t know anything about them. He also would rather not write his own GC.