linux-hardening - [PATCH 0/2] Fix energy-pkg event for AMD CPUs

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Date: Thu, 2 May 2024 15:21:13 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: <tglx@...utronix.de>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>
CC: <peterz@...radead.org>, <mingo@...hat.com>, <ananth.narayan@....com>,
	<gautham.shenoy@....com>, <linux-perf-users@...r.kernel.org>,
	<linux-hardening@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<sandipan.das@....com>, <alexander.shishkin@...ux.intel.com>,
	<irogers@...gle.com>, <gustavoars@...nel.org>, <kprateek.nayak@....com>,
	<ravi.bangoria@....com>, Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Subject: [PATCH 0/2] Fix energy-pkg event for AMD CPUs

After commit 63edbaa48a57 ("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(), no longer return 
the package cpumask and package id, instead they return the CCD (Core 
Complex Die) mask and CCD id respectively. This leads to the energy-pkg 
event scope to be modified to CCD instead of package.

This is functionally incorrect as the AMD energy-pkg is a package scope 
event.

On a 12 CCD 1 Package AMD Zen4 Genoa machine:

$ cat /sys/devices/power/cpumask
0,8,16,24,32,40,48,56,64,72,80,88.

Expected cpumask for 1 Package AMD CPUs energy-pkg event is supposed to 
be just "0".

This in turn leads to incorrect values of package energy consumption.

$ perf stat -C 100 -e power/energy-pkg/ sleep 1

 Performance counter stats for 'CPU(s) 100':

             36.60 Joules power/energy-pkg/

       1.005821050 seconds time elapsed

$ perf stat -a -e power/energy-pkg/ sleep 1

 Performance counter stats for 'system wide':

            414.03 Joules power/energy-pkg/

       1.005252132 seconds time elapsed

In both cases the energy consumption values should have been the same,
but instead, due to the incorrect cpumask, the values are being
aggregated at a CCD level in the second case.

Replacing the die macros with the package macros(for AMD CPUs) fixes 
this issue. 

This patch cleanly applies on top of tip/master after
commit acf68d98cae8 ("perf/x86/rapl: Add support for Intel Lunar Lake"),
but not on Linus' tree.

Dhananjay Ugwekar (2):
  perf/x86/rapl: Rename maxdie to nr_rapl_pmu and dieid to rapl_pmu_idx
  perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

 arch/x86/events/rapl.c | 44 +++++++++++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 11 deletions(-)

-- 
2.34.1