From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2 0/22] KVM: optimize for MMIO handled Date: Wed, 29 Jun 2011 12:23:53 +0300 Message-ID: <4E0AEF29.7080706@redhat.com> References: <4E01FBC9.3020009@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , LKML , KVM To: Xiao Guangrong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55255 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752312Ab1F2JX7 (ORCPT ); Wed, 29 Jun 2011 05:23:59 -0400 In-Reply-To: <4E01FBC9.3020009@cn.fujitsu.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/22/2011 05:27 PM, Xiao Guangrong wrote: > In this version, we fix the bugs in the v1: > - fix broken read emulation spans a page boundary > - fix invalid spte point is got if we walk shadow page table > out of the mmu lock > > And, we also introduce some rules to modify spte in this version, > then it does not need to atomically clear/set spte on x86_32 host > anymore, the performance report of x86_32 host is in the later section > > Avi, > > I have sampled the operation of lockless shadow page walking as below steps: > - mark walk_shadow_page_get_mmio_spte as 'noinline' > - do the netperf test, the client is on the guest(NIC is e1000) and the server > is on the host, it can generate large press of mmio access > - using perf to sample it, and the result of 'perf report' is attached > > The ratio of walk_shadow_page_get_mmio_spte is 0.09%, the ratio of handle_ept_misconfig > is 0.11%, the ratio of handle_mmio_page_fault_common is 0.07% > > I think it is acceptable, your opinion? > Yes. The patchset scares me, but it is nice work! Good optimization and good clean up. -- error compiling committee.c: too many arguments to function