Re: amd ryzen PR 52966

[Maxime Villard <max%m00nbsd.net@localhost>]

Le 08/08/2018 à 10:31, Lars Reichardt a écrit :
> I've run an updated kernel yesterday with the new (AMD) errata fixes.
> (src/sys/arch/x86/x86/errata.c rev 1.24)
> No patches got applied at least nothing was indicated via dmesg I
> assume the firmware did apply those fixes or the zen+ has them fixed.

To see the messages you need to boot with "boot netbsd -v -x". Not all
errata can be fixed by the bios, some are marked in the spec as "no
fix planned".

> src/sys/arch/x86/x86/identcpu.c got patched to use FPU_SAVE_XSAVEOPT if
> present and if present switch to eager fpu context switching.
>
> With this change present I run the stream benchmark noted in
> PR port-amd64/52966
> without any problems on a Ryzen 2700.
> Several runs while doing a release build as well as on an otherwise
> idle machine. (All resulting in: "Solution validates")

Can you test with EagerFPU disabled? Originally, in the PR, Michael was
using !EagerFPU.