Ignatios Souvatzis wrote:
>>An immediate drawback is that not all architectures support the cmpxchg
>>instruction.

Out of curiosity, anybody have an idea what fraction of NetBSD
supported MP architectures (maybe weighted by prominence?) have a
cmpxchg instruction (or a loadlinked/storeconditional, lwarx/stwcx
or other feature that can be used to the purpose)?

I notice that the JACK Audio Connection Kit (which it might be nice
to be able to port) likes to do userspace lock-free stuff with shared
memory.

-Chap