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[v4,03/12] KVM: x86/pmu: Rewrite reprogram_counters() to improve performance

Message ID 20230214050757.9623-4-likexu@tencent.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86: Add AMD Guest PerfMonV2 PMU support | expand

Commit Message

Like Xu Feb. 14, 2023, 5:07 a.m. UTC 
From: Like Xu <likexu@tencent.com>

A valid pmc is always tested before using pmu->reprogram_pmi. Eliminate
this part of the redundancy by setting the counter's bitmask directly,
and in addition, trigger KVM_REQ_PMU only once to save more cpu cycles.

Signed-off-by: Like Xu <likexu@tencent.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 6a2f8b4ed061..069e1aae418c 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -73,16 +73,16 @@  static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
 	}
 }
 
-static void reprogram_counters(struct kvm_pmu *pmu, u64 diff)
+static inline void reprogram_counters(struct kvm_pmu *pmu, u64 diff)
 {
 	int bit;
-	struct kvm_pmc *pmc;
 
-	for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX) {
-		pmc = intel_pmc_idx_to_pmc(pmu, bit);
-		if (pmc)
-			kvm_pmu_request_counter_reprogam(pmc);
-	}
+	if (!diff)
+		return;
+
+	for_each_set_bit(bit, (unsigned long *)&diff, X86_PMC_IDX_MAX)
+		set_bit(bit, pmu->reprogram_pmi);
+	kvm_make_request(KVM_REQ_PMU, pmu_to_vcpu(pmu));
 }
 
 static bool intel_hw_event_available(struct kvm_pmc *pmc)