From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 4F3455F0001 for ; Mon, 6 Apr 2009 07:20:04 -0400 (EDT) Message-ID: <49D9E53D.5080807@redhat.com> Date: Mon, 06 Apr 2009 14:19:25 +0300 From: Izik Eidus MIME-Version: 1.0 Subject: Re: [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 References: <1238855722-32606-1-git-send-email-ieidus@redhat.com> <200904061704.50052.nickpiggin@yahoo.com.au> In-Reply-To: <200904061704.50052.nickpiggin@yahoo.com.au> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Nick Piggin Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, avi@redhat.com, aarcange@redhat.com, chrisw@redhat.com, mtosatti@redhat.com, hugh@veritas.com, kamezawa.hiroyu@jp.fujitsu.com List-ID: Nick Piggin wrote: > On Sunday 05 April 2009 01:35:18 Izik Eidus wrote: > > >> This driver is very useful for KVM as in cases of runing multiple guests >> operation system of the same type. >> (For desktop work loads we have achived more than x2 memory overcommit >> (more like x3)) >> > > Interesting that it is a desirable workload to have multiple guests each > running MS office. > This numbers are took from such workload, it is some kind of weird script that keep opening Word / Excel and write there like a user... I think in addition it open internet explorer and enter to random sites... I can search for the script if wanted... > I wonder, can windows enter a paravirtualised guest mode for KVM? And can > you detect page allocation/freeing events? > I Dont know. > > >> This driver have found users other than KVM, for example CERN, >> Fons Rademakers: >> "on many-core machines we run one large detector simulation program per core. >> These simulation programs are identical but run each in their own process and >> need about 2 - 2.5 GB RAM. >> We typically buy machines with 2GB RAM per core and so have a problem to run >> one of these programs per core. >> Of the 2 - 2.5 GB about 700MB is identical data in the form of magnetic field >> maps, detector geometry, etc. >> Currently people have been trying to start one program, initialize the geometry >> and field maps and then fork it N times, to have the data shared. >> With KSM this would be done automatically by the system so it sounded extremely >> attractive when Andrea presented it." >> > > They should use a shared memory segment, or MAP_ANONYMOUS|MAP_SHARED etc. > Presumably they will probably want to control it to interleave it over > all numa nodes and use hugepages for it. It would be very little work. > Agree about that, dont know their application to much, i know they had problems to do it. > > >> I am sending another seires of patchs for kvm kernel and kvm-userspace >> that would allow users of kvm to test ksm with it. >> The kvm patchs would apply to Avi git tree. >> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org