[Python-Dev] Removing the GIL (Me, not you!) (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Thu Sep 13 06:42:18 CEST 2007

What do you think?

I think what you are describing is the situation of today, except in a less-performant way. The kernel already implements such a "synchronization server", except that all CPUs can act as such. You write

"Since we are guaranteeing that synchronized code is running on a single core, it is the equivalent of a lock at the cost of a context switch."

This is precisely what a lock costs today: a context switch.

Since the Python interpreter is synchronized all of the time, it would completely run on the synchronization server all of the time. As you identify, that single CPU might get overloaded, so your scheme would give no benefits (since Python code could never run in parallel), and only disadvantages (since multiple Python interpreters today can run on multiple CPUs, but could not anymore under your scheme).

Regards, Martin

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