Re: [PATCH 09/10] x86-32: use SSE for atomic64_read/set if available

From: H. Peter Anvin
Date: Thu Feb 18 2010 - 13:28:42 EST


On 02/18/2010 10:14 AM, Luca Barbieri wrote:
>
>> I really feel that without a *strong* use case for this, there is
>> absolutely no point.
> For the specific 32-bit atomic64_t case, it is an improvement, but not
> necessarily significant in the big picture.
> Being able to efficiently use SSE in the kernel might however be more
> broadly useful.
> memcpy/memset/etc. (assuming SSE is the best option for these at least
> on some processors) and checksums come to mind.
> Also non-temporal SSE moves might be useful for things like memory
> compaction without clobbering caches.

We already do that kind of stuff, using
kernel_fpu_begin()..kernel_fpu_end(). We went through some pain a bit
ago to clean up "private hacks" that complicated things substantially.

-hpa
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