From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2] KVM: APIC: avoid instruction emulation for EOI writes Date: Tue, 30 Aug 2011 13:57:09 +0300 Message-ID: <4E5CC205.9020806@redhat.com> References: <625BA99ED14B2D499DC4E29D8138F15063045B0F67@shsmsx502.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "kvm@vger.kernel.org" , "Nakajima, Jun" , "Dong, Eddie" , Marcelo Tosatti , Jan Kiszka , Sasha Levin To: "Tian, Kevin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8803 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753006Ab1H3K5Q (ORCPT ); Tue, 30 Aug 2011 06:57:16 -0400 In-Reply-To: <625BA99ED14B2D499DC4E29D8138F15063045B0F67@shsmsx502.ccr.corp.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/30/2011 04:15 AM, Tian, Kevin wrote: > v2 changes: > define exit qualification fields for APIC-Access in vmx.h > use apic_reg_write instead of apic_set_eoi, to avoid breaking tracing > add fasteoi option to allow disabling this acceleration > > ---- > > commit 2a66a12cb6928c962d24907e6d39b6eb9ac94b4b > Author: Kevin Tian > Date: Mon Aug 29 13:08:28 2011 +0800 > > KVM: APIC: avoid instruction emulation for EOI writes > > Instruction emulation for EOI writes can be skipped, since sane > guest simply uses MOV instead of string operations. This is a nice > improvement when guest doesn't support x2apic or hyper-V EOI > support. > > a single VM bandwidth is observed with ~8% bandwidth improvement > (7.4Gbps->8Gbps), by saving ~5% cycles from EOI emulation. > > Thanks, applied. Please use git format-patch (and git send-email) instead of git show in the future. -- error compiling committee.c: too many arguments to function