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Mon, 27 Apr 2020 20:45:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726257AbgD1ApY (ORCPT ); Mon, 27 Apr 2020 20:45:24 -0400 Received: from mail-ot1-x343.google.com (mail-ot1-x343.google.com [IPv6:2607:f8b0:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9AF6C03C1A8; Mon, 27 Apr 2020 17:45:24 -0700 (PDT) Received: by mail-ot1-x343.google.com with SMTP id i27so29722536ota.7; Mon, 27 Apr 2020 17:45:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Cb11Hz0A50XPcbceB5dfVGRAlvbIEBuFr97ApgK/EIk=; b=dfX+cUxbNOS4J9ZCOwQpOqI92SoKUcnor4d3XsnJ4WIy7r01vyToWMna64GFtWnLCP AcutTza8nkh1hyhiRFV/7y/d+8Ff6tIfVKG59Fmmwbd4PDDpZ+3nk5lKyowA5pfJbrQt 6ixen0G9HUIfyDcex4mza/kOS45Pa5YaQFcLG+7ujYI8zcw7FHyW/DfLCeoPZs50Yruw dQhr9GnCPBQ6y2e7S84+LA1YY+Z+YiKk1llyLUTWaEG9ME4sMHd4cRBirvdGmwZgRquk s22MNyb83XKAzJIv/wSFqMpjcm8LDat4o4nlpaH0/w78pyPtWV0ZJMTIIFnzD3NrV6yS Sidg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Cb11Hz0A50XPcbceB5dfVGRAlvbIEBuFr97ApgK/EIk=; b=beAod2YoRdU6UieqYW6ZvZH0K9zw8s8R0iRhW7mLhEKB0BolU6cetS+atBjSsIXwZe CVFgabPt+wYWDeU0b/XQ8mrWXu3RBD3XuxkfPzY7cY2PgUUce5V0ngDH5hpfaGWhnllq 1a5pWZFzvQtYrKE9hwvCe18EtiXMeKuDxJBwYIcSmVS/t2tmH2ICyDaWrZs5ewrHsqyo lGK0fIVA9mGe6vL//ha13AqFpbCoJQSsnspsUsd1CY+aagrx+YUJ/cVEatvJZRiwwImj TWUZ/QKWxjZ5tKHUTVebVlVkdB4hnIzq/WpMi1Q/IKWPMpV7UgxZ4CccmE92FqYHnn01 M2YQ== X-Gm-Message-State: AGi0PuaWyqwD5RB1xLyN3j63KrQOlH7FrYvYh6TMsc16CIV979x4v53H vNT+BMaio2/F2XpUkIthJW7KFlSbu9OcozSe4R0= X-Google-Smtp-Source: APiQypIYhx+Tjrfud5bCA777zLf4UxvF2A1uz559fKwaXGVCs30bAwIoZRpiDrVm0IZl58QX359yfiaIn8N6PIXHX/0= X-Received: by 2002:a9d:7f04:: with SMTP id j4mr21498257otq.185.1588034724101; Mon, 27 Apr 2020 17:45:24 -0700 (PDT) MIME-Version: 1.0 References: <1587709364-19090-1-git-send-email-wanpengli@tencent.com> <1587709364-19090-6-git-send-email-wanpengli@tencent.com> <20200427184253.GR14870@linux.intel.com> In-Reply-To: <20200427184253.GR14870@linux.intel.com> From: Wanpeng Li Date: Tue, 28 Apr 2020 08:45:13 +0800 Message-ID: Subject: Re: [PATCH v3 5/5] KVM: VMX: Handle preemption timer fastpath To: Sean Christopherson Cc: LKML , kvm , Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Haiwei Li Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 28 Apr 2020 at 02:42, Sean Christopherson wrote: > > On Fri, Apr 24, 2020 at 02:22:44PM +0800, Wanpeng Li wrote: > > From: Wanpeng Li > > > > This patch implements handle preemption timer fastpath, after timer fire > > due to VMX-preemption timer counts down to zero, handle it as soon as > > possible and vmentry immediately without checking various kvm stuff when > > possible. > > > > Testing on SKX Server. > > > > cyclictest in guest(w/o mwait exposed, adaptive advance lapic timer is default -1): > > > > 5540.5ns -> 4602ns 17% > > > > kvm-unit-test/vmexit.flat: > > > > w/o avanced timer: > > tscdeadline_immed: 2885 -> 2431.25 15.7% > > tscdeadline: 5668.75 -> 5188.5 8.4% > > > > w/ adaptive advance timer default -1: > > tscdeadline_immed: 2965.25 -> 2520 15.0% > > tscdeadline: 4663.75 -> 4537 2.7% > > > > Tested-by: Haiwei Li > > Cc: Haiwei Li > > Signed-off-by: Wanpeng Li > > --- > > arch/x86/kvm/vmx/vmx.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > > index d21b66b..028967a 100644 > > --- a/arch/x86/kvm/vmx/vmx.c > > +++ b/arch/x86/kvm/vmx/vmx.c > > @@ -6560,12 +6560,28 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) > > } > > } > > > > +static enum exit_fastpath_completion handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu) > > Somewhat offtopic, would it make sense to add a fastpath_t typedef? These > enum lines are a bit long... > > > +{ > > + struct vcpu_vmx *vmx = to_vmx(vcpu); > > + > > + if (!vmx->req_immediate_exit && > > + !unlikely(vmx->loaded_vmcs->hv_timer_soft_disabled)) { > > Bad indentation. > > Also, this is is identical to handle_preemption_timer(), why not something > like: > > static bool __handle_preemption_timer(struct vcpu) > { > struct vcpu_vmx *vmx = to_vmx(vcpu); > > if (!vmx->req_immediate_exit && > !unlikely(vmx->loaded_vmcs->hv_timer_soft_disabled)) { > kvm_lapic_expired_hv_timer(vcpu); > return true; > } > > return false; > } > > static enum exit_fastpath_completion handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu) > { > if (__handle_preemption_timer(vcpu)) > return EXIT_FASTPATH_CONT_RUN; > return EXIT_FASTPATH_NONE; > } > > static int handle_preemption_timer(struct kvm_vcpu *vcpu) > { > __handle_preemption_timer(vcpu); > return 1; > } > Great! Thanks for making this nicer. Wanpeng