The armv8pmu_enable_event_counter function issues an isb instruction
after enabling a pair of counters - this doesn't provide any value
and is inconsistent with the armv8pmu_disable_event_counter.
In any case armv8pmu_enable_event_counter is always called with the
PMU stopped. Starting the PMU with armv8pmu_start results in an isb
instruction being issued prior to writing to PMCR_EL0.
Let's remove the unnecessary isb instruction.
Signed-off-by: Andrew Murray <andrew.mur...@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poul...@arm.com>
Acked-by: Mark Rutland <mark.rutl...@arm.com>
---
arch/arm64/kernel/perf_event.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 8e38d52..de564ae 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -652,7 +652,6 @@ static inline void armv8pmu_enable_event_counter(struct
perf_event *event)
armv8pmu_enable_counter(idx);
if (armv8pmu_event_is_chained(event))
armv8pmu_enable_counter(idx - 1);
- isb();
}
static inline int armv8pmu_disable_counter(int idx)
--
2.7.4
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