Messages in this thread | | | Date | Mon, 15 Jun 2009 14:30:55 +1000 | From | Paul Mackerras <> | Subject | Re: [PATCH 1/2] lib: Provide generic atomic64_t implementation |
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Roland Dreier writes:
> FWIW, Nehalem EX actually goes to 8 cores/16 threads per socket. But > worrying about 32-bit performance on Nehalem is a little silly -- this > simplest solution is simply to run a 64-bit kernel.
I'm not worried about ANY x86 processor, 32-bit or 64-bit, in fact, since x86 already has an atomic64_t implementation for both 32-bit and 64-bit.
It is interesting, though, that arch/x86/include/asm/atomic_32.h unconditionally uses cmpxchg8b to implement atomic64_t, but I thought that cmpxchg8b didn't exist in processors prior to the Pentium. Presumably you can't use perf_counters on a 386 or 486.
Paul.
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