[PATCH] Add benchmarking-only mode to the test suite

Yi Kong kongy.dev at gmail.com
Wed Jun 4 02:13:47 PDT 2014


Hi Hal Finkel,

I've been running the benchmarking mode for almost two weeks and
didn't seem to miss any performance regression compared to full run. I
think you should commit the patch.

-Yi

On 23 May 2014 18:22, Yi Kong <kongy.dev at gmail.com> wrote:
> On 23 May 2014 17:38, Tobias Grosser <tobias at grosser.es> wrote:
>> So what do these numbers tell us? We have a lot more cache misses in the
>> first run. however, the ratio (66%) remains identical. Does this mean we
>> load values in generally a lot more often? That seems surprising.
>
> L1 cache misses count varies greatly, which means once L1d cache is
> full, the behaviour becomes really unpredictable.
>
>>
>>> Hal, can you add -DSMALL_DATASET to Makefile or change the array size
>>> for STANDARD_DATASET to avoid filling up L1d cache?
>>
>>
>> The interesting optimization problem here is exactly cache behavior. By
>> using -DSMALL_DATASET we just avoid it and can measure it any more. That
>> would be unfortunate.
>
> Otherwise they produce lots of false positives, especially on systems
> with small cache. We could revert it once Polly is capable of
> optimizing these code to a decent state for benchmarking.
>
>> Cheers,
>> Tobias



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