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Date:   Sat, 03 Apr 2021 12:49:32 +0000
To:     Borislav Petkov <bp@alien8.de>, Paul Menzel <pmenzel@molgen.mpg.de>
From:   Thomas Backlund <tmb@tmb.nu>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, x86@kernel.org,
        LKML <linux-kernel@vger.kernel.org>, Song Liu <song@kernel.org>,
        linux-raid@vger.kernel.org, it+linux-x86@molgen.mpg.de
Reply-To: Thomas Backlund <tmb@tmb.nu>
Subject: =?utf-8?Q?Re:_[regression_5.4.97_=E2=86=92_5.10.24]:_raid6_avx2x4_speed_drops_from_18429_MB/s_to_6155_MB/s?=
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Den 2021-04-02 kl. 17:05, skrev Borislav Petkov:
> On Fri, Apr 02, 2021 at 10:33:51AM +0200, Paul Menzel wrote:
>> Dear Linux folks,
>>
>>
>> On an two socket AMD EPYC 7601, we noticed a decrease in raid6 avx2x4 sp=
eed
>> shown at the beginning of the boot.
>>
>>                         5.4.95        5.10.24
>> ----------------------------------------------
>> raid6: avx2x4 gen()   18429 MB/s     6155 MB/s
>> raid6: avx2x4 xor()    6644 MB/s     4274 MB/s
>> raid6: avx2x2 gen()   17894 MB/s    18744 MB/s
>> raid6: avx2x2 xor()   11642 MB/s    11950 MB/s
>> raid6: avx2x1 gen()   13992 MB/s    17112 MB/s
>> raid6: avx2x1 xor()   10855 MB/s    11143 MB/s
>
> Looks like those two might help:
>

That would mean only this is missing:
> 49200d17d27d x86/fpu/64: Don't FNINIT in kernel_fpu_begin()


as this one landed in 5.10.11:
> e45122893a98 x86/fpu: Add kernel_fpu_begin_mask() to selectively initiali=
ze state
>

--
Thomas