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 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
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
