diff options
| author | Wanpeng Li <wanpengli@tencent.com> | 2020-02-26 05:41:02 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-16 19:57:39 +0300 |
| commit | 4abaffce4d25aa41392d2e81835592726d757857 (patch) | |
| tree | 320b25cf896492063edcab40c3173e7a3e967bfb /arch/x86/kvm/lapic.h | |
| parent | 49f933d445b611a237a4687ec7135b57b6b2cfba (diff) | |
| download | linux-4abaffce4d25aa41392d2e81835592726d757857.tar.xz | |
KVM: LAPIC: Recalculate apic map in batch
In the vCPU reset and set APIC_BASE MSR path, the apic map will be recalculated
several times, each time it will consume 10+ us observed by ftrace in my
non-overcommit environment since the expensive memory allocate/mutex/rcu etc
operations. This patch optimizes it by recaluating apic map in batch, I hope
this can benefit the serverless scenario which can frequently create/destroy
VMs.
Before patch:
kvm_lapic_reset ~27us
After patch:
kvm_lapic_reset ~14us
Observed by ftrace, improve ~48%.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/lapic.h')
| -rw-r--r-- | arch/x86/kvm/lapic.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index ec6fbfe325cf..7581bc2dcd47 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -78,6 +78,7 @@ void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8); void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu); void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value); u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu); +void kvm_recalculate_apic_map(struct kvm *kvm); void kvm_apic_set_version(struct kvm_vcpu *vcpu); int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val); int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len, |