Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH v2 2/2] x86: add prefetching to do_csum | Date | Wed, 06 Nov 2013 12:19:52 -0800 |
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Neil Horman <nhorman@tuxdriver.com> writes:
> do_csum was identified via perf recently as a hot spot when doing > receive on ip over infiniband workloads. After alot of testing and > ideas, we found the best optimization available to us currently is to > prefetch the entire data buffer prior to doing the checksum
On what CPU? Most modern CPUs should not have any trouble at all prefetching a linear access.
Also for large buffers it is unlikely that all the prefetches are actually executed, there is usually some limit.
As a minimum you would need: - run it with a range of buffer sizes - run this on a range of different CPUs and show no major regressions - describe all of this actually in the description
But I find at least this patch very dubious.
-Andi
-- ak@linux.intel.com -- Speaking for myself only
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