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| author |   Mark Rutland <mark.rutland@arm.com> | 2016-09-09 14:08:30 +0100 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2016-09-09 14:51:51 +0100 |
| commit | 48538b5863d8e8f8d567fc9a1d27a68623e0a0ff (patch) | |
| tree | bf2feca2a3cd582ed4d0f52b16ed83e1350321f5 /include/linux/perf | |
| parent | drivers/perf: arm_pmu: only use common attr_groups (diff) | |
| download | linux-dev-48538b5863d8e8f8d567fc9a1d27a68623e0a0ff.tar.xz linux-dev-48538b5863d8e8f8d567fc9a1d27a68623e0a0ff.zip | |
drivers/perf: arm_pmu: expose a cpumask in sysfs
In systems with heterogeneous CPUs, there are multiple logical CPU PMUs,
each of which covers a subset of CPUs in the system. In some cases
userspace needs to know which CPUs a given logical PMU covers, so we'd
like to expose a cpumask under sysfs, similar to what is done for uncore
PMUs.
Unfortunately, prior to commit 00e727bb389359c8 ("perf stat: Balance
opening and reading events"), perf stat only correctly handled a cpumask
holding a single CPU, and only when profiling in system-wide mode. In
other cases, the presence of a cpumask file could cause perf stat to
behave erratically.
Thus, exposing a cpumask file would break older perf binaries in cases
where they would otherwise work.
To avoid this issue while still providing userspace with the information
it needs, this patch exposes a differently-named file (cpus) under
sysfs. New tools can look for this and operate correctly, while older
tools will not be adversely affected by its presence.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'include/linux/perf')
| -rw-r--r-- | include/linux/perf/arm_pmu.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 268bc63f1358..dc1f2f30c961 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -78,6 +78,7 @@ struct pmu_hw_events { }; enum armpmu_attr_groups { + ARMPMU_ATTR_GROUP_COMMON, ARMPMU_ATTR_GROUP_EVENTS, ARMPMU_ATTR_GROUP_FORMATS, ARMPMU_NR_ATTR_GROUPS |