From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756933Ab2GFKc5 (ORCPT ); Fri, 6 Jul 2012 06:32:57 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:48719 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756599Ab2GFKc4 (ORCPT ); Fri, 6 Jul 2012 06:32:56 -0400 X-AuditID: b753bd60-9b4f4ba000000f6c-df-4ff6bed5e951 X-AuditID: b753bd60-9b4f4ba000000f6c-df-4ff6bed5e951 Message-ID: <4FF6BEDC.8040207@hitachi.com> Date: Fri, 06 Jul 2012 19:33:00 +0900 From: Tomoki Sekiyama User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: avi@redhat.com Cc: jan.kiszka@siemens.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, yrl.pp-manager.tt@hitachi.com Subject: Re: [RFC PATCH 00/18] KVM: x86: CPU isolation and direct interrupts handling by guests References: <20120628060719.19298.43879.stgit@localhost.localdomain> <4FEC8D31.3070406@redhat.com> <4FEC93BD.2070809@siemens.com> <4FEC95BC.200@redhat.com> <4FED7495.30707@hitachi.com> <4FEDC22F.9070406@redhat.com> In-Reply-To: <4FEDC22F.9070406@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2012/06/29 23:56, Avi Kivity wrote: >> On 2012/06/29 2:34, Avi Kivity wrote: >>> On 06/28/2012 08:26 PM, Jan Kiszka wrote: >>>>> This is both impressive and scary. What is the target scenario here? >>>>> Partitioning? I don't see this working for generic consolidation. >>>> >>>> From my POV, partitioning - including hard realtime partitions - would >>>> provide some use cases. >> >> Exactly this is for partitioning that requires bare-metal performance >> with low latency and realtime. > > It's hard for me to evaluate how large that segment is. Since the > patchset is so intrusive, it needs a large potential user set to > justify, or a large reduction in complexity, or both. Low latency or realtime is often required on high-end systems like trading, automated control, HPC and so on, or for multimedias. Those who want to run MRG as a guest, or to fully utilize high-speed NIC are also worth using this. And not all of such applications does not use up every CPU, so partitioning is becoming reasonable as a number of cores in a server is increasing. Anyway, I will try to make the patch as simple as possible. >> I think it is also useful for workload >> like HPC with MPI, that is CPU intensive and that needs low latency. > > I keep hearing about people virtualizing these types of workloads, but I > haven't yet understood why. One reason is ease of deployment of applications to nodes. Especially in IaaS environment like Amazon EC2 Cluster Compute Instances, virtualization is often introduced as a simple way to move applications around flexibly among nodes shared by many users. Thanks, -- Tomoki Sekiyama Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory