From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuanhan Liu Subject: Re: [PATCH 0/6] vhost: add Tx zero copy support Date: Fri, 23 Sep 2016 12:11:26 +0800 Message-ID: <20160923041126.GO23158@yliu-dev.sh.intel.com> References: <1471939839-29778-1-git-send-email-yuanhan.liu@linux.intel.com> <82F45D86ADE5454A95A89742C8D1410E39110B70@SHSMSX104.ccr.corp.intel.com> <82F45D86ADE5454A95A89742C8D1410E39110BE5@SHSMSX104.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Xu, Qian Q" , Maxime Coquelin To: "dev@dpdk.org" Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 8D50F5921 for ; Fri, 23 Sep 2016 06:11:01 +0200 (CEST) Content-Disposition: inline In-Reply-To: <82F45D86ADE5454A95A89742C8D1410E39110BE5@SHSMSX104.ccr.corp.intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Mon, Aug 29, 2016 at 08:57:52AM +0000, Xu, Qian Q wrote: > Btw, some good news: if I run a simple dequeue workload (running rxonly in vhost-pmd and runnin txonly in guest testpmd), it yields ~50% performance boost for packet size 1518B, but this case is without NIC. > And similar case as vhost<-->virtio loopback, we can see ~10% performance gains at 1518B without NIC. > > Some bad news: If with the patch, I noticed a 3%-7% performance drop if zero-copy=0 compared with current DPDK(e.g: 16.07) at vhost/virtio loopback and vhost RX only + virtio TX only. Seems the patch will > Impact the zero-copy=0 performance a little. There are some follow up discussion internally, the 3%-7% drop reported by Qian when zero-copy is not enabled is acutally due to the fluctuation. So, a false alarm. --yliu