Re: unknown NMI on AMD Rome

[Alexander Monakov]

On Tue, 16 Mar 2021, Adam Borowski wrote:

> On Tue, Mar 16, 2021 at 04:45:02PM +0100, Jiri Olsa wrote:
> > hi,
> > when running 'perf top' on AMD Rome (/proc/cpuinfo below)
> > with fedora 33 kernel 5.10.22-200.fc33.x86_64
> > 
> > we got unknown NMI messages:
> > 
> > [  226.700160] Uhhuh. NMI received for unknown reason 3d on CPU 90.
> > [  226.700162] Do you have a strange power saving mode enabled?
> > [  226.700163] Dazed and confused, but trying to continue
> > 
> > also when discussing ths with Borislav, he managed to reproduce easily
> > on his AMD Rome machine
> 
> Likewise, 3c on Pinnacle Ridge.

I've also seen it on Renoir, and it appears related to PMU interrupt racing
against C-state entry/exit. Disabling C2 and C3 via 'cpupower' is enough to
avoid those NMIs in my case.

IIRC there were a few patches related to this area from AMD in the past.

Alexander