From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Sean Christopherson" <sean.j.christopherson@intel.com>,
"Liran Alon" <liran.alon@oracle.com>
Subject: [PATCH v3 1/5] KVM: LAPIC: Extract adaptive tune timer advancement logic
Date: Thu, 16 May 2019 11:06:16 +0800 [thread overview]
Message-ID: <1557975980-9875-2-git-send-email-wanpengli@tencent.com> (raw)
In-Reply-To: <1557975980-9875-1-git-send-email-wanpengli@tencent.com>
From: Wanpeng Li <wanpengli@tencent.com>
Extract adaptive tune timer advancement logic to a single function.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 57 ++++++++++++++++++++++++++++++----------------------
1 file changed, 33 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index bd13fdd..2f364fe 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1501,11 +1501,40 @@ static inline void __wait_lapic_expire(struct kvm_vcpu *vcpu, u64 guest_cycles)
}
}
-void wait_lapic_expire(struct kvm_vcpu *vcpu)
+static inline void adaptive_tune_timer_advancement(struct kvm_vcpu *vcpu,
+ u64 guest_tsc, u64 tsc_deadline)
{
struct kvm_lapic *apic = vcpu->arch.apic;
u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns;
- u64 guest_tsc, tsc_deadline, ns;
+ u64 ns;
+
+ /* too early */
+ if (guest_tsc < tsc_deadline) {
+ ns = (tsc_deadline - guest_tsc) * 1000000ULL;
+ do_div(ns, vcpu->arch.virtual_tsc_khz);
+ timer_advance_ns -= min((u32)ns,
+ timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
+ } else {
+ /* too late */
+ ns = (guest_tsc - tsc_deadline) * 1000000ULL;
+ do_div(ns, vcpu->arch.virtual_tsc_khz);
+ timer_advance_ns += min((u32)ns,
+ timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
+ }
+
+ if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE)
+ apic->lapic_timer.timer_advance_adjust_done = true;
+ if (unlikely(timer_advance_ns > 5000)) {
+ timer_advance_ns = 0;
+ apic->lapic_timer.timer_advance_adjust_done = true;
+ }
+ apic->lapic_timer.timer_advance_ns = timer_advance_ns;
+}
+
+void wait_lapic_expire(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+ u64 guest_tsc, tsc_deadline;
if (apic->lapic_timer.expired_tscdeadline == 0)
return;
@@ -1521,28 +1550,8 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)
if (guest_tsc < tsc_deadline)
__wait_lapic_expire(vcpu, tsc_deadline - guest_tsc);
- if (!apic->lapic_timer.timer_advance_adjust_done) {
- /* too early */
- if (guest_tsc < tsc_deadline) {
- ns = (tsc_deadline - guest_tsc) * 1000000ULL;
- do_div(ns, vcpu->arch.virtual_tsc_khz);
- timer_advance_ns -= min((u32)ns,
- timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
- } else {
- /* too late */
- ns = (guest_tsc - tsc_deadline) * 1000000ULL;
- do_div(ns, vcpu->arch.virtual_tsc_khz);
- timer_advance_ns += min((u32)ns,
- timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
- }
- if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE)
- apic->lapic_timer.timer_advance_adjust_done = true;
- if (unlikely(timer_advance_ns > 5000)) {
- timer_advance_ns = 0;
- apic->lapic_timer.timer_advance_adjust_done = true;
- }
- apic->lapic_timer.timer_advance_ns = timer_advance_ns;
- }
+ if (unlikely(!apic->lapic_timer.timer_advance_adjust_done))
+ adaptive_tune_timer_advancement(vcpu, guest_tsc, tsc_deadline);
}
static void start_sw_tscdeadline(struct kvm_lapic *apic)
--
2.7.4
next prev parent reply other threads:[~2019-05-16 3:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 3:06 [PATCH v3 0/5] KVM: LAPIC: Optimize timer latency further Wanpeng Li
2019-05-16 3:06 ` Wanpeng Li [this message]
2019-05-16 3:06 ` [PATCH v3 2/5] KVM: LAPIC: Fix lapic_timer_advance_ns parameter overflow Wanpeng Li
2019-05-16 3:06 ` [PATCH v3 3/5] KVM: LAPIC: Expose per-vCPU timer_advance_ns to userspace Wanpeng Li
2019-05-17 20:05 ` Sean Christopherson
2019-05-20 8:43 ` Wanpeng Li
2019-05-16 3:06 ` [PATCH v3 4/5] KVM: LAPIC: Delay trace advance expire delta Wanpeng Li
2019-05-17 19:44 ` Sean Christopherson
2019-05-20 6:38 ` Wanpeng Li
2019-05-20 14:56 ` Sean Christopherson
2019-05-16 3:06 ` [PATCH v3 5/5] KVM: LAPIC: Optimize timer latency further Wanpeng Li
2019-05-17 19:50 ` Sean Christopherson
2019-05-20 8:19 ` Wanpeng Li
2019-05-20 15:08 ` Sean Christopherson
2019-06-12 9:35 [PATCH v3 0/5] " Wanpeng Li
2019-06-12 9:35 ` [PATCH v3 1/5] KVM: LAPIC: Extract adaptive tune timer advancement logic Wanpeng Li
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