From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuanhan Liu Subject: Re: [PATCH v4] vhost: Add indirect descriptors support to the TX path Date: Tue, 27 Sep 2016 20:18:38 +0800 Message-ID: <20160927121838.GO25823@yliu-dev.sh.intel.com> References: <1474619303-16709-1-git-send-email-maxime.coquelin@redhat.com> <1474965769-24782-1-git-send-email-maxime.coquelin@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: huawei.xie@intel.com, dev@dpdk.org, vkaplans@redhat.com, mst@redhat.com, stephen@networkplumber.org To: Maxime Coquelin Return-path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 2D62612A8 for ; Tue, 27 Sep 2016 14:18:11 +0200 (CEST) Content-Disposition: inline In-Reply-To: <1474965769-24782-1-git-send-email-maxime.coquelin@redhat.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 Tue, Sep 27, 2016 at 10:42:49AM +0200, Maxime Coquelin wrote: > Indirect descriptors are usually supported by virtio-net devices, > allowing to dispatch a larger number of requests. > > When the virtio device sends a packet using indirect descriptors, > only one slot is used in the ring, even for large packets. > > The main effect is to improve the 0% packet loss benchmark. > A PVP benchmark using Moongen (64 bytes) on the TE, and testpmd > (fwd io for host, macswap for VM) on DUT shows a +50% gain for > zero loss. > > On the downside, micro-benchmark using testpmd txonly in VM and > rxonly on host shows a loss between 1 and 4%.i But depending on > the needs, feature can be disabled at VM boot time by passing > indirect_desc=off argument to vhost-user device in Qemu. > > Signed-off-by: Maxime Coquelin Applied to dpdk-next-virtio. Thanks. --yliu