Python subinterpreters with separate GILs

[Cameron Simpson]

On 10Feb2021 21:51, James Lu <jamtlu at gmail.com> wrote:
>Directly removing the Global Interpreter Lock (GIL) would break a lot
>of libraries that implicitly assume it is there. What if Python had
>"realms" that each had separate GILs?
>
>The "realms" (not sure if "subinterpreter" is the correct term here)
>could share objects.

If realms can shared objects then they'd need the same GIL, because 
otherwise objects are not protected from concurrency via different 
realms. CPython code and C code, unless it has itself released the GIL, 
assumes it is the exclusive user of objects - that's what the GIL means.  
Separate GILs would mean different realms' GIL-holding threads could run 
against a shared object at the same time.

Cheers,
Cameron Simpson <cs at cskk.id.au>