Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754644Ab0HCIsS (ORCPT ); Tue, 3 Aug 2010 04:48:18 -0400 Received: from mga01.intel.com ([192.55.52.88]:30962 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752171Ab0HCIsP convert rfc822-to-8bit (ORCPT ); Tue, 3 Aug 2010 04:48:15 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.55,308,1278313200"; d="scan'208";a="824197826" From: "Xin, Xiaohui" To: Shirley Ma CC: "netdev@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "mst@redhat.com" , "mingo@elte.hu" , "davem@davemloft.net" , "herbert@gondor.apana.org.au" , "jdike@linux.intel.com" Date: Tue, 3 Aug 2010 16:48:08 +0800 Subject: RE: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net. Thread-Topic: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net. Thread-Index: AcsvbdP2So8Wpr8uSbuirl5Bo+pEOQDeh58g Message-ID: References: <1280402088-5849-1-git-send-email-xiaohui.xin@intel.com> <1280442682.9058.15.camel@localhost.localdomain> In-Reply-To: <1280442682.9058.15.camel@localhost.localdomain> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2280 Lines: 58 >-----Original Message----- >From: Shirley Ma [mailto:mashirle@us.ibm.com] >Sent: Friday, July 30, 2010 6:31 AM >To: Xin, Xiaohui >Cc: netdev@vger.kernel.org; kvm@vger.kernel.org; linux-kernel@vger.kernel.org; >mst@redhat.com; mingo@elte.hu; davem@davemloft.net; herbert@gondor.apana.org.au; >jdike@linux.intel.com >Subject: Re: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net. > >Hello Xiaohui, > >On Thu, 2010-07-29 at 19:14 +0800, xiaohui.xin@intel.com wrote: >> The idea is simple, just to pin the guest VM user space and then >> let host NIC driver has the chance to directly DMA to it. >> The patches are based on vhost-net backend driver. We add a device >> which provides proto_ops as sendmsg/recvmsg to vhost-net to >> send/recv directly to/from the NIC driver. KVM guest who use the >> vhost-net backend may bind any ethX interface in the host side to >> get copyless data transfer thru guest virtio-net frontend. > >Since vhost-net already supports macvtap/tun backends, do you think >whether it's better to implement zero copy in macvtap/tun than inducing >a new media passthrough device here? > >> Our goal is to improve the bandwidth and reduce the CPU usage. >> Exact performance data will be provided later. > >I did some vhost performance measurement over 10Gb ixgbe, and found that >in order to get consistent BW results, netperf/netserver, qemu, vhost >threads smp affinities are required. > >Looking forward to these results for small message size comparison. For >large message size 10Gb ixgbe BW already reached by doing vhost smp >affinity w/i offloading support, we will see how much CPU utilization it >can be reduced. > >Please provide latency results as well. I did some experimental on >macvtap zero copy sendmsg, what I have found that get_user_pages latency >pretty high. > May you share me with your performance results (including BW and latency)on vhost-net and how you get them(your configuration and especially with the affinity settings)? Thanks Xiaohui >Thanks >Shirley > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/