Re: [REDO PATCH v7] perf/x86/amd/power: Add AMD accumulated power reporting mechanism

From: Vince Weaver
Date: Fri Jun 17 2016 - 11:54:29 EST


On Fri, 17 Jun 2016, Huang Rui wrote:

> Can you try to read the MSR value two times with the same core
> (rdmsrl_on_cpu)?

I'm reading from userspace using the /dev/cpu/0/msr device so it should
always be reading from cpu0.

I guess I could code up a custom kernel module to debug this if necessary.

It does look that for some reason the 0xc0010280 MSR is only returning the
lower 24 bits of the PTSC, rather than the 40 bits that
cpuid 80000008:ecx seems to think it should have.

Vince