Re: [PATCH] Add memcpy_nc, a copy routine that tries to keep cachepressure down

From: Arjan van de Ven
Date: Sat Jul 01 2006 - 04:27:20 EST


On Fri, 2006-06-30 at 21:56 -0700, Bryan O'Sullivan wrote:
> This copy routine is memcpy-compatible, but on some architectures will use
> cache-bypassing loads to avoid bringing the source data into the cache.
>
> One case where this is useful is when a device issues a DMA to a memory
> region, and the CPU must copy the DMAed data elsewhere before doing any
> work with it. Since the source data is read-once, write-never from the
> CPU's perspective, caching those addresses can only evict potentially
> useful data.
>
> We provide an x86_64 implementation that uses SSE non-temporal loads,
> and a generic version that falls back to plain memcpy.

Hi,

can we give this a more descriptive name please? Say
memcpy_cachebypass() or something? "_nc" doesn't say a lot of things to
many people... which means it'll either not get used when it should, or
it gets used when it shouldn't....

Greetings,
Arjan van de Ven

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