linux-kernel - Re: [PATCH v3] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

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Message-ID: <ZtmC8hhpUvQTXFDn@gmail.com>
Date: Thu, 5 Sep 2024 12:07:46 +0200
From: Ingo Molnar <mingo@...nel.org>
To: "Liang, Kan" <kan.liang@...ux.intel.com>
Cc: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>, peterz@...radead.org,
	mingo@...hat.com, acme@...nel.org, namhyung@...nel.org,
	mark.rutland@....com, alexander.shishkin@...ux.intel.com,
	jolsa@...nel.org, irogers@...gle.com, adrian.hunter@...el.com,
	tglx@...utronix.de, bp@...en8.de, dave.hansen@...ux.intel.com,
	x86@...nel.org, hpa@...or.com, gautham.shenoy@....com,
	ravi.bangoria@....com, linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs


* Liang, Kan <kan.liang@...ux.intel.com> wrote:

> 
> 
> On 2024-09-04 6:09 a.m., Dhananjay Ugwekar wrote:
> > After commit ("x86/cpu/topology: Add support for the AMD 0x80000026 leaf"),
> > on AMD processors that support extended CPUID leaf 0x80000026, the
> > topology_die_cpumask() and topology_logical_die_id() macros, no longer
> > return the package cpumask and package id, instead they return the CCD
> > (Core Complex Die) mask and id respectively. This leads to the energy-pkg
> > event scope to be modified to CCD instead of package.
> > 
> > So, change the PMU scope for AMD and Hygon back to package.
> > 
> > On a 12 CCD 1 Package AMD Zen4 Genoa machine:
> > 
> > Before:
> > $ cat /sys/devices/power/cpumask
> > 0,8,16,24,32,40,48,56,64,72,80,88.
> > 
> > The expected cpumask here is supposed to be just "0", as it is a package
> > scope event, only one CPU will be collecting the event for all the CPUs in
> > the package.
> > 
> > After:
> > $ cat /sys/devices/power/cpumask
> > 0
> > 
> > Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
> 
> Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>

Note that I just merged the older v2 version into perf/urgent, because it's 
a regression fix, and to not create a backporting complication. I added 
your Reviewed-by to it if that's fine with you.

Your hotplug series can essentially revert this:

  8d72eba1cf8c ("perf/x86/rapl: Fix the energy-pkg event for AMD CPUs")

and apply the v3 patch to gain the simpler version.

Thanks,

	Ingo