From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [kvm-devel] performance with guests running 2.4 kernels (specifically RHEL3) Date: Thu, 29 May 2008 14:49:37 +0300 Message-ID: <483E9851.2040306@qumranet.com> References: <482C1633.5070302@qumranet.com> <482E5F9C.6000207@cisco.com> <482FCEE1.5040306@qumranet.com> <4830F90A.1020809@cisco.com> <4830FE8D.6010006@cisco.com> <48318E64.8090706@qumranet.com> <4832DDEB.4000100@qumranet.com> <4835EEF5.9010600@cisco.com> <483D391F.7050007@qumranet.com> <483D6898.2050605@cisco.com> <20080528144850.GX27375@duo.random> <483D72D1.7080803@qumranet.com> <483D7CC6.5000708@cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Andrea Arcangeli , kvm@vger.kernel.org To: "David S. Ahern" Return-path: Received: from bzq-179-150-194.static.bezeqint.net ([212.179.150.194]:29855 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752109AbYE2Ltl (ORCPT ); Thu, 29 May 2008 07:49:41 -0400 In-Reply-To: <483D7CC6.5000708@cisco.com> Sender: kvm-owner@vger.kernel.org List-ID: David S. Ahern wrote: > I've been instrumenting the guest kernel as well. It's the scanning of > the active lists that triggers a lot of calls to paging64_prefetch_page, > and, as you guys know, correlates with the number of direct pages in the > list. Earlier in this thread I traced the kvm cycles to > paging64_prefetch_page(). See > I optimized this function a bit, hopefully it will relieve some of the pain. We still need to reduce the number of times it is called. -- error compiling committee.c: too many arguments to function