Re: AMD Athlon bogus performance value causing RCU stalls?

[Rob Prowel]

On 09/23/18 17:19, Thomas Gleixner wrote:
> > Other than RTFM, or please build a bunch of kernels from source on your slow
> > machine, using differing config options to help track down the cause of
> > this...any thoughts about a solution?
>
> Yes. This was decoded recently as an issue on 32bit due to a calculation
> which is based on 'unsigned long' but requires to be 64bit wide.
>
> It's in the 4.18.8 stable kernel, which should be available from your
> fedora repo anytime soon.

OK.  Followup on AMD performance counter problem in 4.18.7

The Dell machine I was experiencing the problem on had a lot of ACPI
issues.  One of the invalid ACPI entries was for a system timer.
dmesg suggests that the broken timer was used in calculating the
Athlon performance value.  So no, 32/64 bit math was not the issue.

ACPI=off in the kernel boot line fixed the issue completely. Machine
still functions well as a file/web/postgresql dev server so it's all
good.

tanks!