From: Wanpeng Li <kernellwp@gmail.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kvm <kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
Yunhong Jiang <yunhong.jiang@intel.com>,
Wanpeng Li <wanpeng.li@hotmail.com>
Subject: Re: [PATCH v3 5/5] KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support
Date: Tue, 25 Oct 2016 07:33:02 +0800 [thread overview]
Message-ID: <CANRm+Cxz5GAQXKKZzc86ey6qXEVqxraZvsmQPAzK8Gx_3GYPFw@mail.gmail.com> (raw)
In-Reply-To: <20161024145016.GA2247@potion>
2016-10-24 22:50 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>:
> 2016-10-24 18:23+0800, Wanpeng Li:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> Most windows guests still utilize APIC Timer periodic/oneshot mode
>> instead of tsc-deadline mode, and the APIC Timer periodic/oneshot
>> mode are still emulated by high overhead hrtimer on host. This patch
>> converts the expected expire time of the periodic/oneshot mode to
>> guest deadline tsc in order to leverage VMX preemption timer logic
>> for APIC Timer tsc-deadline mode. After each preemption timer vmexit
>> preemption timer is restarted to emulate LVTT current-count register
>> is automatically reloaded from the initial-count register when the
>> count reaches 0. This patch reduces ~5600 cycles for each APIC Timer
>> periodic mode operation virtualization.
>>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim Krčmář <rkrcmar@redhat.com>
>> Cc: Yunhong Jiang <yunhong.jiang@intel.com>
>> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
>> ---
>> arch/x86/kvm/lapic.c | 117 ++++++++++++++++++++++++++++++++++++++-------------
>> arch/x86/kvm/lapic.h | 1 +
>> 2 files changed, 89 insertions(+), 29 deletions(-)
>>
>> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
>> @@ -2005,8 +2060,12 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
>>
>> if (atomic_read(&apic->lapic_timer.pending) > 0) {
>> kvm_apic_local_deliver(apic, APIC_LVTT);
>> - if (apic_lvtt_tscdeadline(apic))
>> + if (apic_lvtt_period(apic))
>
> This should remain apic_lvtt_tscdeadline(). I can change that when
> applying to kvm/queue.
Thanks Radim, I make a mistake here.
Regards,
Wanpeng Li
>
>> + apic->lapic_timer.tscdeadline = 0;
>> + if (apic_lvtt_oneshot(apic)) {
>> apic->lapic_timer.tscdeadline = 0;
>> + apic->lapic_timer.target_expiration = ktime_set(0, 0);
>> + }
>> atomic_set(&apic->lapic_timer.pending, 0);
>> }
>> }
next prev parent reply other threads:[~2016-10-24 23:33 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-24 10:23 [PATCH v3 0/5] KVM: LAPIC: Add APIC Timer periodic/oneshot mode VMX preemption timer support Wanpeng Li
2016-10-24 10:23 ` [PATCH v3 1/5] KVM: LAPIC: extract start_sw_period() to handle periodic/oneshot mode Wanpeng Li
2016-10-24 10:23 ` [PATCH v3 2/5] KVM: LAPIC: guarantee the timer is in tsc-deadline mode Wanpeng Li
2016-10-24 10:23 ` [PATCH v3 3/5] KVM: LAPIC: introduce kvm_get_lapic_target_expiration_tsc() Wanpeng Li
2016-10-24 10:23 ` [PATCH v3 4/5] KVM: LAPIC: rename start/cancel_hv_tscdeadline to start/cancel_hv_timer Wanpeng Li
2016-10-24 10:23 ` [PATCH v3 5/5] KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support Wanpeng Li
2016-10-24 14:50 ` Radim Krčmář
2016-10-24 23:33 ` Wanpeng Li [this message]
2016-10-24 15:03 ` [PATCH 6/5] KVM: x86: fix periodic lapic timer with hrtimers Radim Krčmář
2016-10-24 15:09 ` Paolo Bonzini
2016-10-24 15:27 ` Radim Krčmář
2016-10-24 23:39 ` Wanpeng Li
2016-10-25 11:43 ` Radim Krčmář
2016-10-25 11:55 ` Paolo Bonzini
2016-10-26 6:02 ` Wanpeng Li
2016-10-26 6:08 ` Wanpeng Li
2016-10-26 14:01 ` Radim Krčmář
2016-10-27 2:33 ` Wanpeng Li
2016-10-26 13:32 ` Radim Krčmář
2016-10-27 2:11 ` Wanpeng Li
2016-10-26 10:23 ` Wanpeng Li
2016-10-26 11:15 ` Paolo Bonzini
2016-10-26 11:26 ` Wanpeng Li
[not found] ` <SG2PR02MB1550E0FF04F2614BE0E262BC80A80@SG2PR02MB1550.apcprd02.prod.outlook.com>
2016-10-25 13:03 ` Radim Krčmář
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