From 649bccd7fac98225525c79cf4b1cecc4bafdfc54 Mon Sep 17 00:00:00 2001 From: Like Xu Date: Tue, 14 Feb 2023 13:07:48 +0800 Subject: [PATCH] KVM: x86/pmu: Rewrite reprogram_counters() to improve performance 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 Link: https://lore.kernel.org/r/20230214050757.9623-4-likexu@tencent.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/pmu_intel.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index c45bd10..eb291df 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -76,13 +76,13 @@ 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) { 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) -- 2.7.4