Re: [PATCH v5 07/14] perf bench mem: Allow chunking on a memory region

[Ankur Arora <ankur.a.arora@oracle.com>]

Namhyung Kim <namhyung@kernel.org> writes:

> On Wed, Jul 09, 2025 at 05:59:19PM -0700, Ankur Arora wrote:
>> There can be a significant gap in memset/memcpy performance depending
>> on the size of the region being operated on.
>>
>> With chunk-size=4kb:
>>
>>   $ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
>>
>>   $ perf bench mem memset -p 4kb -k 4kb -s 4gb -l 10 -f x86-64-stosq
>>   # Running 'mem/memset' benchmark:
>>   # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S)
>>   # Copying 4gb bytes ...
>>
>>       13.011655 GB/sec
>>
>> With chunk-size=1gb:
>>
>>   $ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
>>
>>   $ perf bench mem memset -p 4kb -k 1gb -s 4gb -l 10 -f x86-64-stosq
>>   # Running 'mem/memset' benchmark:
>>   # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S)
>>   # Copying 4gb bytes ...
>>
>>       21.936355 GB/sec
>>
>> So, allow the user to specify the chunk-size.
>>
>> The default value is identical to the total size of the region, which
>> preserves current behaviour.
>>
>> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
>
> Again, please update the documentation.  With that,
>
> Reviewed-by: Namhyung Kim <namhyung@kernel.org>
>
Thanks! Will do.

--
ankur