From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161108Ab2COQ6v (ORCPT ); Thu, 15 Mar 2012 12:58:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9860 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031844Ab2COQ6s (ORCPT ); Thu, 15 Mar 2012 12:58:48 -0400 Message-ID: <4F621FC0.7050800@redhat.com> Date: Thu, 15 Mar 2012 18:58:40 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120216 Thunderbird/10.0.1 MIME-Version: 1.0 To: Akshay Karle CC: linux-kernel@vger.kernel.org, Dan Magenheimer , konrad.wilk@oracle.com, kvm@vger.kernel.org, ashu tripathi , nishant gulhane , amarmore2006 , Shreyas Mahure , mahesh mohan Subject: Re: [RFC 0/2] kvm: Transcendent Memory (tmem) on KVM References: <1331224181.2585.16.camel@aks> In-Reply-To: <1331224181.2585.16.camel@aks> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/08/2012 06:29 PM, Akshay Karle wrote: > Hi, > > We are undergraduate engineering students of Maharashtra Academy of > Engineering, Pune, India and we are working on a project entitled > 'Transcendent Memory on KVM' as a part of our academics. > The project members are: > 1. Ashutosh Tripathi > 2. Shreyas Mahure > 3. Nishant Gulhane > 4. Akshay Karle > > --- > Project Description: > What is Transcendent Memory(tmem in short)? > Transcendent Memory is a memory optimization technique for the > virtualized environment. It collects the underutilized memory of the > guests and the unassigned(fallow) memory of the host and places it into > a central tmem pool. Indirect access to this pool is then provided to the guests. > For further information on tmem, please refer the article on lwn by Dr. > Dan Magenheimer: > http://lwn.net/Articles/454795/ > > Since kvm is one of the most popular hypervisors available, > we decided to implement this technique for kvm. > > Any comments/feedback would be appreciated and will help us a lot with our work. > One of the potential problems with tmem is reduction in performance when the cache hit rate is low, for example when streaming. Can you test this by creating a large file, for example with dd < /dev/urandom > file bs=1M count=100000 and then measuring the time to stream it, using time dd < file > /dev/null with and without the patch? Should be done on a cleancache enabled guest filesystem backed by a virtio disk with cache=none. It would be interesting to compare kvm_stat during the streaming, with and without the patch. -- error compiling committee.c: too many arguments to function