1999d7c47SAthira RajeevWhat: /sys/bus/event_source/devices/<dev>/caps 2999d7c47SAthira RajeevDate: May 2022 3999d7c47SAthira RajeevKernelVersion: 5.19 4999d7c47SAthira RajeevContact: Linux kernel mailing list <linux-kernel@vger.kernel.org> 5999d7c47SAthira RajeevDescription: 6999d7c47SAthira Rajeev Attribute group to describe the capabilities exposed 7999d7c47SAthira Rajeev for a particular pmu. Each attribute of this group can 8999d7c47SAthira Rajeev expose information specific to a PMU, say pmu_name, so that 9999d7c47SAthira Rajeev userspace can understand some of the feature which the 10999d7c47SAthira Rajeev platform specific PMU supports. 11999d7c47SAthira Rajeev 12999d7c47SAthira Rajeev One of the example available capability in supported platform 13999d7c47SAthira Rajeev like Intel is pmu_name, which exposes underlying CPU name known 14999d7c47SAthira Rajeev to the PMU driver. 15999d7c47SAthira Rajeev 16999d7c47SAthira Rajeev Example output in powerpc: 17999d7c47SAthira Rajeev grep . /sys/bus/event_source/devices/cpu/caps/* 18999d7c47SAthira Rajeev /sys/bus/event_source/devices/cpu/caps/pmu_name:POWER9 19*571d91dcSKan Liang 20*571d91dcSKan Liang The "branch_counter_nr" in the supported platform exposes the 21*571d91dcSKan Liang maximum number of counters which can be shown in the u64 counters 22*571d91dcSKan Liang of PERF_SAMPLE_BRANCH_COUNTERS, while the "branch_counter_width" 23*571d91dcSKan Liang exposes the width of each counter. Both of them can be used by 24*571d91dcSKan Liang the perf tool to parse the logged counters in each branch. 25