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