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