From: Ilkka Koskinen <ilkka@os.amperecomputing.com> mainline inclusion from mainline-v6.12-rc1 commit 5967a19f1c2ffb530f5d4589ddc4b4afbb6c7bd4 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/9455 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ----------------------------------------------- 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> Signed-off-by: Yushan Wang <wangyushan12@huawei.com> Signed-off-by: Ying Jiang <jiangying44@h-partners.com> --- drivers/perf/arm_pmuv3.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 5d750678a70e..d112d904c8c9 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -1419,14 +1419,14 @@ 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; } -- 2.43.0