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authorKan Liang <kan.liang@linux.intel.com>2024-07-08 12:33:36 -0700
committerPeter Zijlstra <peterz@infradead.org>2024-07-09 13:26:39 +0200
commite5f32ad56b22ebe384a6e7ddad6e9520c5495563 (patch)
treeddc98776788318bca8a68b58f541342698364600 /Documentation/admin-guide/pm/cpufreq.rst
parent556a7c039a52c21da33eaae9269984a1ef59189b (diff)
perf/x86/intel/ds: Fix non 0 retire latency on Raptorlake
A non-0 retire latency can be observed on a Raptorlake which doesn't support the retire latency feature. By design, the retire latency shares the PERF_SAMPLE_WEIGHT_STRUCT sample type with other types of latency. That could avoid adding too many different sample types to support all kinds of latency. For the machine which doesn't support some kind of latency, 0 should be returned. Perf doesn’t clear/init all the fields of a sample data for the sake of performance. It expects the later perf_{prepare,output}_sample() to update the uninitialized field. However, the current implementation doesn't touch the field of the retire latency if the feature is not supported. The memory garbage is dumped into the perf data. Clear the retire latency if the feature is not supported. Fixes: c87a31093c70 ("perf/x86: Support Retire Latency") Reported-by: "Bayduraev, Alexey V" <alexey.v.bayduraev@intel.com> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: "Bayduraev, Alexey V" <alexey.v.bayduraev@intel.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20240708193336.1192217-4-kan.liang@linux.intel.com
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