Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] Add memcpy_cachebypass, a copy routine that tries to keep cache pressure down | From | Arjan van de Ven <> | Date | Tue, 11 Jul 2006 22:56:38 +0200 |
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On Tue, 2006-07-11 at 13:50 -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. > > Implementors for other arches should not use cache-bypassing stores to > the destination, as in most cases, the destination is accessed almost > immediately after a copy finishes. > > Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com> > Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Acked-by: Arjan van de Ven <arjan@Linux.intel.com>
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