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perf/x86/rapl: fix AMD event handling
The RAPL events exposed under /sys/devices/power/events should only reflect what the underlying hardware actually support. This is how it works on Intel RAPL and Intel core/uncore PMUs in general. But on AMD, this was not the case. All possible RAPL events were advertised. This is what it showed on an AMD Fam17h: $ ls /sys/devices/power/events/ energy-cores energy-gpu energy-pkg energy-psys energy-ram energy-cores.scale energy-gpu.scale energy-pkg.scale energy-psys.scale energy-ram.scale energy-cores.unit energy-gpu.unit energy-pkg.unit energy-psys.unit energy-ram.unit Yet, on AMD Fam17h, only energy-pkg is supported. This patch fixes the problem. Given the way perf_msr_probe() works, the amd_rapl_msrs[] table has to have all entries filled out and in particular the group field, otherwise perf_msr_probe() defaults to making the event visible. With the patch applied, the kernel now only shows was is actually supported: $ ls /sys/devices/power/events/ energy-pkg energy-pkg.scale energy-pkg.unit The patch also uses the RAPL_MSR_MASK because only the 32-bits LSB of the RAPL counters are relevant when reading power consumption. Signed-off-by: Stephane Eranian <eranian@google.com>
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