lkml.org 
[lkml]   [2006]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] Add memcpy_cachebypass, a copy routine that tries to keep cache pressure down
From
Date
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>


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-07-11 22:59    [W:0.067 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site