[PATCH 1/2] benchtests: Memory walking benchmark for memcpy
Carlos O'Donell
carlos@redhat.com
Thu Sep 21 18:29:00 GMT 2017
On 09/18/2017 11:40 AM, Siddhesh Poyarekar wrote:
> This benchmark is an attempt to eliminate cache effects from string
> benchmarks. The benchmark walks both ways through a large memory area
> and copies different sizes of memory and alignments one at a time
> instead of looping around in the same memory area. This is a good
> metric to have alongside the other memcpy benchmarks, especially for
> larger sizes where the likelihood of the call being done only once is
> pretty high.
>
> The benchmark is unlike other string benchmarks in that it prints the
> total data rate achieved during a walk across the memory and not the
> time taken per execution.
>
> * benchtests/bench-memcpy-walk.c: New file.
> * benchtests/Makefile (string-benchset): Add it.
I like the idea, and the point that the other benchmark eventually degrades
into measuring L1 performance an interesting insight.
I do not like that it produces total data rate not time taken per execution.
Why the change? If time taken per execution was OK before, why not here?
--
Cheers,
Carlos.
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