• Wanpeng Li's avatar
    KVM: X86: Improve latency for single target IPI fastpath · a9ab13ff
    Wanpeng Li authored
    IPI and Timer cause the main MSRs write vmexits in cloud environment
    observation, let's optimize virtual IPI latency more aggressively to
    inject target IPI as soon as possible.
    
    Running kvm-unit-tests/vmexit.flat IPI testing on SKX server, disable
    adaptive advance lapic timer and adaptive halt-polling to avoid the
    interference, this patch can give another 7% improvement.
    
    w/o fastpath   -> x86.c fastpath      4238 -> 3543  16.4%
    x86.c fastpath -> vmx.c fastpath      3543 -> 3293     7%
    w/o fastpath   -> vmx.c fastpath      4238 -> 3293  22.3%
    
    Cc: Haiwei Li <lihaiwei@tencent.com>
    Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
    Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
    Message-Id: <20200410174703.1138-3-sean.j.christopherson@intel.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    a9ab13ff
x86.c 276 KB