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| author | Athira Rajeev <atrajeev@linux.vnet.ibm.com> | 2022-02-02 07:18:37 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:23:27 +0300 |
| commit | 94fd8a2a47c8fd52ff67fe3a55cb80489e02a476 (patch) | |
| tree | 732bf4b17df76fc392939c916a35fb657d3933c2 /arch/powerpc | |
| parent | 0dc750479a5ffe32149a5212ca349c9392af62d3 (diff) | |
| download | linux-94fd8a2a47c8fd52ff67fe3a55cb80489e02a476.tar.xz | |
powerpc/perf: Don't use perf_hw_context for trace IMC PMU
[ Upstream commit 0198322379c25215b2778482bf1221743a76e2b5 ]
Trace IMC (In-Memory collection counters) in powerpc is useful for
application level profiling.
For trace_imc, presently task context (task_ctx_nr) is set to
perf_hw_context. But perf_hw_context should only be used for CPU PMU.
See commit 26657848502b ("perf/core: Verify we have a single
perf_hw_context PMU").
So for trace_imc, even though it is per thread PMU, it is preferred to
use sw_context in order to be able to do application level monitoring.
Hence change the task_ctx_nr to use perf_sw_context.
Fixes: 012ae244845f ("powerpc/perf: Trace imc PMU functions")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Update subject & incorporate notes into change log, reflow comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220202041837.65968-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/perf/imc-pmu.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c index e106909ff9c3..e7583fbcc8fa 100644 --- a/arch/powerpc/perf/imc-pmu.c +++ b/arch/powerpc/perf/imc-pmu.c @@ -1457,7 +1457,11 @@ static int trace_imc_event_init(struct perf_event *event) event->hw.idx = -1; - event->pmu->task_ctx_nr = perf_hw_context; + /* + * There can only be a single PMU for perf_hw_context events which is assigned to + * core PMU. Hence use "perf_sw_context" for trace_imc. + */ + event->pmu->task_ctx_nr = perf_sw_context; event->destroy = reset_global_refc; return 0; } |