diff options
| author | Ilkka Koskinen <ilkka@os.amperecomputing.com> | 2024-09-06 21:15:39 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2024-09-09 16:28:02 +0200 |
| commit | 5967a19f1c2ffb530f5d4589ddc4b4afbb6c7bd4 (patch) | |
| tree | de72cb3e9e4afd3256290b28d0101174ec97b1a7 /drivers/perf | |
| parent | MAINTAINERS: List Arm interconnect PMUs as supported (diff) | |
| download | linux-5967a19f1c2ffb530f5d4589ddc4b4afbb6c7bd4.tar.xz linux-5967a19f1c2ffb530f5d4589ddc4b4afbb6c7bd4.zip | |
perf: arm_pmuv3: Use BR_RETIRED for HW branch event if enabled
The PMU driver attempts to use PC_WRITE_RETIRED for the HW branch event,
if enabled. However, PC_WRITE_RETIRED counts only taken branches,
whereas BR_RETIRED counts also non-taken ones.
Furthermore, perf uses HW branch event to calculate branch misses ratio,
implying BR_RETIRED is the correct event to count.
We keep PC_WRITE_RETIRED still as an option in case BR_RETIRED isn't
implemented.
Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20240906191539.4847-1-ilkka@os.amperecomputing.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/perf')
| -rw-r--r-- | drivers/perf/arm_pmuv3.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 4d000532a07f..0afe02f879b4 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -1086,14 +1086,14 @@ static int __armv8_pmuv3_map_event_id(struct arm_pmu *armpmu, if (event->attr.type == PERF_TYPE_HARDWARE && event->attr.config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) { - if (test_bit(ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED, - armpmu->pmceid_bitmap)) - return ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED; - if (test_bit(ARMV8_PMUV3_PERFCTR_BR_RETIRED, armpmu->pmceid_bitmap)) return ARMV8_PMUV3_PERFCTR_BR_RETIRED; + if (test_bit(ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED, + armpmu->pmceid_bitmap)) + return ARMV8_PMUV3_PERFCTR_PC_WRITE_RETIRED; + return HW_OP_UNSUPPORTED; } |