From de73708915adc1b3f05e617a86da6b2d68fae141 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 21 Jun 2018 10:43:59 +0100 Subject: KVM: arm/arm64: Enable adaptative WFE trapping Trapping blocking WFE is extremely beneficial in situations where the system is oversubscribed, as it allows another thread to run while being blocked. In a non-oversubscribed environment, this is the complete opposite, and trapping WFE is just unnecessary overhead. Let's only enable WFE trapping if the CPU has more than a single task to run (that is, more than just the vcpu thread). Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- virt/kvm/arm/arm.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'virt/kvm') diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index 04e554cae3a2..8e66b89a3db2 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -380,6 +381,11 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) kvm_timer_vcpu_load(vcpu); kvm_vcpu_load_sysregs(vcpu); kvm_arch_vcpu_load_fp(vcpu); + + if (single_task_running()) + vcpu_clear_wfe_traps(vcpu); + else + vcpu_set_wfe_traps(vcpu); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) -- cgit v1.2.3