Re: [PATCH v2 1/2] lib/raid6: skip benchmark of non-chosen xor_syndrome functions
From: Song Liu <song@kernel.org>
Date: 2022-01-05 18:55:37
On Wed, Jan 5, 2022 at 8:39 AM Dirk Müller [off-list ref] wrote:
In commit fe5cbc6e06c7 ("md/raid6 algorithms: delta syndrome functions")
a xor_syndrome() benchmarking was added also to the raid6_choose_gen()
function. However, the results of that benchmarking were intentionally
discarded and did not influence the choice. It picked the
xor_syndrome() variant related to the best performing gen_syndrome().
Reduce runtime of raid6_choose_gen() without modifying its outcome by
only benchmarking the xor_syndrome() of the best gen_syndrome() variant.
For a HZ=250 x86_64 system with avx2 and without avx512 this removes
5 out of 6 xor() benchmarks, saving 340ms of raid6 initialization time.
Signed-off-by: Dirk Müller <redacted>Applied both patches to md-next. Thanks, Song