From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id E59B2199B6 for ; Wed, 6 Dec 2017 09:33:58 +0100 (CET) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4366CC04AC4F; Wed, 6 Dec 2017 08:33:58 +0000 (UTC) Received: from [10.36.112.55] (ovpn-112-55.ams2.redhat.com [10.36.112.55]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 249607837F; Wed, 6 Dec 2017 08:33:52 +0000 (UTC) To: Jiayu Hu , dev@dpdk.org Cc: yliu@fridaylinux.org, jianfeng.tan@intel.com References: <1511846913-72414-1-git-send-email-jiayu.hu@intel.com> From: Maxime Coquelin Message-ID: <720f198e-7e6c-7f5a-fc2d-cf303b97f24d@redhat.com> Date: Wed, 6 Dec 2017 09:33:43 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1511846913-72414-1-git-send-email-jiayu.hu@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Wed, 06 Dec 2017 08:33:58 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH] vhost: support Generic Segmentation Offload X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Dec 2017 08:33:59 -0000 Hi Jiayu, On 11/28/2017 06:28 AM, Jiayu Hu wrote: > In virtio, Generic Segmentation Offload (GSO) is the feature for the > backend, which means the backend can receive packets with any GSO > type. > > Virtio-net enables the GSO feature by default, and vhost-net supports it. > To make live migration from vhost-net to vhost-user possible, this patch > enables GSO for vhost-user. Please note that the application relying on Vhost library may disable some features, breaking the migration from vhost-net to vhost-user even if all features are supported in the vhost-user lib. For example, ovs-dpdk disables the following features: err = rte_vhost_driver_disable_features(dev->vhost_id, 1ULL << VIRTIO_NET_F_HOST_TSO4 | 1ULL << VIRTIO_NET_F_HOST_TSO6 | 1ULL << VIRTIO_NET_F_CSUM); > Signed-off-by: Jiayu Hu > --- > lib/librte_vhost/vhost.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > index 1cc81c1..04f54cb 100644 > --- a/lib/librte_vhost/vhost.h > +++ b/lib/librte_vhost/vhost.h > @@ -204,6 +204,7 @@ struct vhost_msg { > (1ULL << VIRTIO_F_VERSION_1) | \ > (1ULL << VHOST_F_LOG_ALL) | \ > (1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \ > + (1ULL << VIRTIO_NET_F_GSO) | \ This feature is also enabled by default in QEMU, and seems also to be acked by default in the virtio-net kernel driver. Does it have an impact on performance? Be it good or bad. How to test it? > (1ULL << VIRTIO_NET_F_HOST_TSO4) | \ > (1ULL << VIRTIO_NET_F_HOST_TSO6) | \ > (1ULL << VIRTIO_NET_F_CSUM) | \ > Thanks, Maxime