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: Mon, 19 May 2008 20:04:50 +0300 Message-ID: <4831B332.9030308@qumranet.com> References: <48054518.3000104@cisco.com> <4805BCF1.6040605@qumranet.com> <4807BD53.6020304@cisco.com> <48085485.3090205@qumranet.com> <480C188F.3020101@cisco.com> <480C5C39.4040300@qumranet.com> <480E492B.3060500@cisco.com> <480EEDA0.3080209@qumranet.com> <480F546C.2030608@cisco.com> <481215DE.3000302@cisco.com> <20080428181550.GA3965@dmt> <4816617F.3080403@cisco.com> <4817F30C.6050308@cisco.com> <48184228.2020701@qumranet.com> <481876A9.1010806@cisco.com> <48187903.2070409@qumranet.com> <4826E744.1080107@qumranet.com> <4826F668.6030305@qumranet.com> <48290FC2.4070505@cisco.com> <48294272.5020801@qumranet.com> <482B4D29.7010202@cisco.com> <482C1633.5070302@qumranet.com> <482E5F9C.6000207@cisco.com> <482FCEE1.5040306@qumranet.com> <4830F90A.1020809@cisco.com> <4830FE8D.6010006@cisco.com> <4 8318E64.8090706@qumranet.com> <4831AA0B.30700@cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: "David S. Ahern" Return-path: Received: from bzq-179-150-194.static.bezeqint.net ([212.179.150.194]:39702 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753947AbYESREv (ORCPT ); Mon, 19 May 2008 13:04:51 -0400 In-Reply-To: <4831AA0B.30700@cisco.com> Sender: kvm-owner@vger.kernel.org List-ID: David S. Ahern wrote: > Does the fact that the hugemem kernel works just fine have any bearing > on your options? Or rather, is there something unique about the way > kscand works in the hugemem kernel that its performance is ok? > > Yes. If your guest has < 4GB of memory, then all of it is lowmem in the hugemem kernel, and the two-step process for modifying a pte is short-circuited into just one step, and everything works fine. -- error compiling committee.c: too many arguments to function