• Wanpeng Li's avatar
    KVM: X86: Narrow down the IPI fastpath to single target IPI · e1be9ac8
    Wanpeng Li authored
    The original single target IPI fastpath patch forgot to filter the
    ICR destination shorthand field. Multicast IPI is not suitable for
    this feature since wakeup the multiple sleeping vCPUs will extend
    the interrupt disabled time, it especially worse in the over-subscribe
    and VM has a little bit more vCPUs scenario. Let's narrow it down to
    single target IPI.
    
    Two VMs, each is 76 vCPUs, one running 'ebizzy -M', the other
    running cyclictest on all vCPUs, w/ this patch, the avg score
    of cyclictest can improve more than 5%. (pv tlb, pv ipi, pv
    sched yield are disabled during testing to avoid the disturb).
    Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
    Message-Id: <1585189202-1708-3-git-send-email-wanpengli@tencent.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    e1be9ac8
x86.c 274 KB