From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751386Ab0IFJOy (ORCPT ); Mon, 6 Sep 2010 05:14:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23775 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824Ab0IFJOw (ORCPT ); Mon, 6 Sep 2010 05:14:52 -0400 Message-ID: <4C84B103.7020603@redhat.com> Date: Mon, 06 Sep 2010 12:14:43 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.8) Gecko/20100806 Fedora/3.1.2-1.fc13 Lightning/1.0b2pre Thunderbird/3.1.2 MIME-Version: 1.0 To: Alexander Graf CC: Xiao Guangrong , Marcelo Tosatti , LKML , KVM Subject: Re: [PATCH] KVM: don't sent IPI if the vcpu is not online References: <4C807593.1050903@cn.fujitsu.com> <4C83445B.4020103@redhat.com> <4C844887.9090802@cn.fujitsu.com> <4C84801F.9060803@redhat.com> <4C84AC6B.4090306@redhat.com> <633F01D5-D6AD-40F3-8864-C3AE4D314E30@suse.de> <4C84AEF5.2070309@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/06/2010 12:09 PM, Alexander Graf wrote: > >> It can also be running host kernel or user code. > In that case it's the same as running guest code, no? We'll pass by the vcpu entry check asap. Sure, but the IPI is wasted. If you spend 10% of your time in host code, you can avoid 10% of the IPIs. (actually less, since the atomic part of the guest switch has guest_mode enabled) -- error compiling committee.c: too many arguments to function