From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx144.postini.com [74.125.245.144]) by kanga.kvack.org (Postfix) with SMTP id 8D59B6B0030 for ; Tue, 29 Jan 2013 05:45:17 -0500 (EST) Date: Tue, 29 Jan 2013 12:45:14 +0200 From: Gleb Natapov Subject: Re: [PATCH 0/11] ksm: NUMA trees and page migration Message-ID: <20130129104513.GA15004@redhat.com> References: <20130128155452.16882a6e.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Andrew Morton , Marcelo Tosatti , Petr Holasek , Andrea Arcangeli , Izik Eidus , Rik van Riel , David Rientjes , Anton Arapov , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org On Mon, Jan 28, 2013 at 05:07:15PM -0800, Hugh Dickins wrote: > On Mon, 28 Jan 2013, Andrew Morton wrote: > > On Fri, 25 Jan 2013 17:53:10 -0800 (PST) > > Hugh Dickins wrote: > > > > > Here's a KSM series > > > > Sanity check: do you have a feeling for how useful KSM is? > > Performance/space improvements for typical (or atypical) workloads? > > Are people using it? Successfully? > > > > IOW, is it justifying itself? > > I have no idea! To me it's simply a technical challenge - and I agree > with your implication that that's not a good enough justification. > > I've added Marcelo and Gleb and the KVM list to the Cc: > my understanding is that it's the KVM guys who really appreciate KSM. > KSM is used on all RH kvm deployments for memory overcommit. I asked around for numbers and got the answer that it allows to squeeze anywhere between 10% and 100% more VMs on the same machine depends on a type of a guest OS and how similar workloads of VMs are. And management tries to keep VMs with similar OSes/workloads on the same host to gain more from KSM. -- Gleb. -- 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