Good to know it works for you.  Keep in mind TIME_QUANTUM_USEC=1000 is
very low and may cause problems on some systems, too.

My gut feeling is 100ms (default) is too high, but 10ms is too low
(based on kosaki's comment).  Maybe 20ms - 50ms is acceptable.  There is
a wide variety of configuration we must work with (even just on Linux).

Can you try 20-50ms?


About GVL:
Replacing GVL with fine-grained locks is possible (and ko1 tried it),
but performance suffered for single-thread cases.
It should be possible to do with lock-free techniques, but that is
difficult to get right.