Messages in this thread | | | Date | Mon, 31 Aug 2015 10:38:21 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 09/15] x86, amd: add accessor for number of cores per compute unit |
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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.
Not to mention the proposed code is horrible, who in their right mind does two rdmsrl_safe_on_cpu() back to back.
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