1What: /sys/bus/event_source/devices/<dev>/caps 2Date: May 2022 3KernelVersion: 5.19 4Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> 5Description: 6 Attribute group to describe the capabilities exposed 7 for a particular pmu. Each attribute of this group can 8 expose information specific to a PMU, say pmu_name, so that 9 userspace can understand some of the feature which the 10 platform specific PMU supports. 11 12 One of the example available capability in supported platform 13 like Intel is pmu_name, which exposes underlying CPU name known 14 to the PMU driver. 15 16 Example output in powerpc: 17 grep . /sys/bus/event_source/devices/cpu/caps/* 18 /sys/bus/event_source/devices/cpu/caps/pmu_name:POWER9 19 20 The "branch_counter_nr" in the supported platform exposes the 21 maximum number of counters which can be shown in the u64 counters 22 of PERF_SAMPLE_BRANCH_COUNTERS, while the "branch_counter_width" 23 exposes the width of each counter. Both of them can be used by 24 the perf tool to parse the logged counters in each branch. 25