linux-kernel - [PATCH 0/3] KVM: lapic: optimize injection of already-expired timer

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Date:   Thu, 29 Jun 2017 18:58:18 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     rkrcmar@...hat.com, wanpeng.li@...mail.com
Subject: [PATCH 0/3] KVM: lapic: optimize injection of already-expired timer

This is my take on Wanpeng's optimization, whose effect I've now measured
with vmexit.flat.  Indeed, without patch 3 the new tscdeadline_immed
benchmark is 50% slower with preemption_timer=1 than with preemption_timer=0.

Patch 1 refactors start_hv_timer to prepare for the next one and to
simplify Wanpeng's patch (a lot).  Patch 2 avoids a bug that I didn't
catch in my earlier review: kvm_x86_ops->set_timer must not be called
directly when the TSC goes backwards.

Paolo

Paolo Bonzini (2):
  KVM: lapic: reorganize start_hv_timer
  KVM: lapic: reorganize restart_apic_timer

Wanpeng Li (1):
  KVM: LAPIC: Fix lapic timer injection delay

 arch/x86/kvm/lapic.c | 116 ++++++++++++++++++++++++++++-----------------------
 arch/x86/kvm/lapic.h |   2 +-
 arch/x86/kvm/vmx.c   |   3 +-
 arch/x86/kvm/x86.c   |   8 ++--
 4 files changed, 71 insertions(+), 58 deletions(-)

-- 
1.8.3.1