* [PATCH] perf/x86/amd: Use faster rdpmc instruction when waiting for overflow
@ 2021-11-16 17:07 Kim Phillips
0 siblings, 0 replies; only message in thread
From: Kim Phillips @ 2021-11-16 17:07 UTC (permalink / raw)
To: Borislav Petkov, Borislav Petkov, Peter Zijlstra, Ingo Molnar,
Ingo Molnar, Thomas Gleixner, kim.phillips
Cc: linux-kernel
The relatively new amd_pmu_wait_on_overflow uses rdmsr.
Update it to use the faster rdpmc instruction.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/events/amd/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 9687a8aef01c..c36cb0c6f9e1 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -587,6 +587,8 @@ static void amd_pmu_cpu_dead(int cpu)
static void amd_pmu_wait_on_overflow(int idx)
{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ struct hw_perf_event *hwc = &cpuc->events[idx]->hw;
unsigned int i;
u64 counter;
@@ -596,7 +598,7 @@ static void amd_pmu_wait_on_overflow(int idx)
* forever...
*/
for (i = 0; i < OVERFLOW_WAIT_COUNT; i++) {
- rdmsrl(x86_pmu_event_addr(idx), counter);
+ rdpmcl(hwc->event_base_rdpmc, counter);
if (counter & (1ULL << (x86_pmu.cntval_bits - 1)))
break;
--
2.32.0
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