diff options
Diffstat (limited to 'meta-arm/meta-arm-bsp/recipes-kernel/linux/linux-arm64-ack-5.15/tc/0021-perf-arm-cmn-Optimise-DTM-counter-reads.patch')
| -rw-r--r-- | meta-arm/meta-arm-bsp/recipes-kernel/linux/linux-arm64-ack-5.15/tc/0021-perf-arm-cmn-Optimise-DTM-counter-reads.patch | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/meta-arm/meta-arm-bsp/recipes-kernel/linux/linux-arm64-ack-5.15/tc/0021-perf-arm-cmn-Optimise-DTM-counter-reads.patch b/meta-arm/meta-arm-bsp/recipes-kernel/linux/linux-arm64-ack-5.15/tc/0021-perf-arm-cmn-Optimise-DTM-counter-reads.patch new file mode 100644 index 0000000000..07e0484318 --- /dev/null +++ b/meta-arm/meta-arm-bsp/recipes-kernel/linux/linux-arm64-ack-5.15/tc/0021-perf-arm-cmn-Optimise-DTM-counter-reads.patch @@ -0,0 +1,56 @@ +From 2919ec562ca976a0ae5f70b264379b3d45abdaf5 Mon Sep 17 00:00:00 2001 +From: Robin Murphy <robin.murphy@arm.com> +Date: Fri, 3 Dec 2021 11:44:56 +0000 +Subject: [PATCH 21/40] perf/arm-cmn: Optimise DTM counter reads + +When multiple nodes of the same type are connected to the same XP +(particularly in CAL configurations), it seems that they are likely +to be consecutive in logical ID. Therefore, we're likely to gain a +small benefit from an easy tweak to optimise out consecutive reads +of the same set of DTM counters for an aggregated event. + +Signed-off-by: Robin Murphy <robin.murphy@arm.com> +Link: https://lore.kernel.org/r/7777d77c2df17693cd3dabb6e268906e15238d82.1638530442.git.robin.murphy@arm.com +Signed-off-by: Will Deacon <will@kernel.org> + +Upstream-Status: Backport [https://lore.kernel.org/r/7777d77c2df17693cd3dabb6e268906e15238d82.1638530442.git.robin.murphy@arm.com] +Signed-off-by: Rupinderjit Singh <rupinderjit.singh@arm.com> +--- + drivers/perf/arm-cmn.c | 17 +++++++++-------- + 1 file changed, 9 insertions(+), 8 deletions(-) + +diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c +index 8b98ca9666d0..005a0d83bcac 100644 +--- a/drivers/perf/arm-cmn.c ++++ b/drivers/perf/arm-cmn.c +@@ -690,18 +690,19 @@ static void arm_cmn_pmu_disable(struct pmu *pmu) + static u64 arm_cmn_read_dtm(struct arm_cmn *cmn, struct arm_cmn_hw_event *hw, + bool snapshot) + { ++ struct arm_cmn_dtm *dtm = NULL; + struct arm_cmn_node *dn; +- unsigned int i, offset; +- u64 count = 0; ++ unsigned int i, offset, dtm_idx; ++ u64 reg, count = 0; + + offset = snapshot ? CMN_DTM_PMEVCNTSR : CMN_DTM_PMEVCNT; + for_each_hw_dn(hw, dn, i) { +- struct arm_cmn_dtm *dtm = &cmn->dtms[dn->dtm]; +- int dtm_idx = arm_cmn_get_index(hw->dtm_idx, i); +- u64 reg = readq_relaxed(dtm->base + offset); +- u16 dtm_count = reg >> (dtm_idx * 16); +- +- count += dtm_count; ++ if (dtm != &cmn->dtms[dn->dtm]) { ++ dtm = &cmn->dtms[dn->dtm]; ++ reg = readq_relaxed(dtm->base + offset); ++ } ++ dtm_idx = arm_cmn_get_index(hw->dtm_idx, i); ++ count += (u16)(reg >> (dtm_idx * 16)); + } + return count; + } +-- +2.34.1 + |