Re: [PATCH 09/15] x86, amd: add accessor for number of cores per compute unit

Peter Zijlstra
2015-08-31T13:38:15Z

On Mon, Aug 31, 2015 at 06:26:00AM -0700, Guenter Roeck wrote:
> On 08/31/2015 01:38 AM, Peter Zijlstra wrote:
> >On Sun, Aug 30, 2015 at 05:53:22PM +0200, Borislav Petkov wrote:
> >>On Sat, Aug 29, 2015 at 11:19:14AM +0200, Ingo Molnar wrote:
> >>>So let me withdraw my ack: the much more important question that I
> >>>missed first time around, why is this reporting feature living in
> >>>hwmon, not in perf? We have energy reporting facilities in perf that
> >>>this should be synced to.
> >>
> >>Because there's already fam15h_power driver which is exactly for that.
> >>Making it part of perf is then a question of cat-ting the same sysfs
> >>file twice, at the beginning and at the end of the trace, which is
> >>trivial.
> >
> >That don't make sense.
> >
> >Looking at the BKDG Fam 15h 60h-6Fh these MSRs are per compute unit.
> >This means you can do much finer grained measurements than system wide
> >-- which is all hwmon seems capable of.
> >
>
> Is it ? Why ?

Dunno, because there's that big old loop iterating all cpus?