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Commit a9ab13ff authored by Wanpeng Li's avatar Wanpeng Li Committed by Paolo Bonzini
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KVM: X86: Improve latency for single target IPI fastpath



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>
parent 873e1da1
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