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From: Paul Menzel <pmenzel@molgen.mpg.de>
To: Borislav Petkov <bp@alien8.de>
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,
	"Krzysztof Olędzki" <ole@ans.pl>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Krzysztof Mazur" <krzysiek@podlesie.net>
Subject: Re: [regression 5.4.97 → 5.10.24]: raid6 avx2x4 speed drops from 18429 MB/s to 6155 MB/s
Date: Tue, 6 Apr 2021 12:58:15 +0200	[thread overview]
Message-ID: <05dbb237-1d23-df32-e4ed-6bc7b47f42dc@molgen.mpg.de> (raw)
In-Reply-To: <20210402140554.GG28499@zn.tnic>

Dear Borislav,


Am 02.04.21 um 16:05 schrieb Borislav Petkov:
> On Fri, Apr 02, 2021 at 10:33:51AM +0200, Paul Menzel wrote:

>> On an two socket AMD EPYC 7601, we noticed a decrease in raid6 avx2x4 speed
>> 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:
> 
> 49200d17d27d x86/fpu/64: Don't FNINIT in kernel_fpu_begin()
> e45122893a98 x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state

I booted Linux 5.12-rc6, containing these commits, on a Dell OptiPlex 
5055 with AMD Ryzen 5 PRO 1500 Quad-Core Processor, and the regression 
is still present for `avx2x4 xor()`:

                         5.4.95       5.10.24
----------------------------------------------
raid6: avx2x4 gen()    23964 MB/s   24540 MB/s 

raid6: avx2x4 xor()    13101 MB/s    8354 MB/s
raid6: avx2x2 gen()    22746 MB/s   26972 MB/s
raid6: avx2x2 xor()    14917 MB/s   16463 MB/s
raid6: avx2x1 gen()    17519 MB/s   24394 MB/s
raid6: avx2x1 xor()    14091 MB/s   15330 MB/s
raid6: sse2x4 gen()    16867 MB/s   16136 MB/s
raid6: sse2x4 xor()     9667 MB/s    8176 MB/s
raid6: sse2x2 gen()    14996 MB/s   18234 MB/s
raid6: sse2x2 xor()    10765 MB/s   10455 MB/s
raid6: sse2x1 gen()     7667 MB/s   13769 MB/s
raid6: sse2x1 xor()     7818 MB/s    7741 MB/s

What system are you using, and what results do you get with 5.4 and 
5.12-rc6?


Kind regards,

Paul

  reply	other threads:[~2021-04-06 10:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-02  8:33 [regression 5.4.97 → 5.10.24]: raid6 avx2x4 speed drops from 18429 MB/s to 6155 MB/s Paul Menzel
2021-04-02 14:05 ` Borislav Petkov
2021-04-06 10:58   ` Paul Menzel [this message]
2021-04-06 12:41     ` Borislav Petkov
  -- strict thread matches above, loose matches on Subject: below --
2021-04-03 12:49 Thomas Backlund

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