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 B3BAA5934 for ; Mon, 17 Oct 2016 16:14:49 +0200 (CEST) Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 23EA0C057FA6; Mon, 17 Oct 2016 14:14:49 +0000 (UTC) Received: from [10.36.5.44] (vpn1-5-44.ams2.redhat.com [10.36.5.44]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u9HEEkfa005360 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 17 Oct 2016 10:14:47 -0400 To: Yuanhan Liu References: <1474619303-16709-1-git-send-email-maxime.coquelin@redhat.com> <1474965769-24782-1-git-send-email-maxime.coquelin@redhat.com> <8F6C2BD409508844A0EFC19955BE09414E7CE6D1@SHSMSX103.ccr.corp.intel.com> <70cc3b89-d680-1519-add3-f38b228e65b5@redhat.com> <20161017132121.GG16751@yliu-dev.sh.intel.com> Cc: "Wang, Zhihong" , "Xie, Huawei" , "dev@dpdk.org" , "vkaplans@redhat.com" , "mst@redhat.com" , "stephen@networkplumber.org" From: Maxime Coquelin Message-ID: Date: Mon, 17 Oct 2016 16:14:45 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20161017132121.GG16751@yliu-dev.sh.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 17 Oct 2016 14:14:49 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to the TX path X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Oct 2016 14:14:50 -0000 On 10/17/2016 03:21 PM, Yuanhan Liu wrote: > On Mon, Oct 17, 2016 at 01:23:23PM +0200, Maxime Coquelin wrote: >>> On my side, I just setup 2 Windows 2016 VMs, and confirm the issue. >>> I'll continue the investigation early next week. >> >> The root cause is identified. >> When INDIRECT_DESC feature is negotiated, Windows guest uses indirect >> for both Tx and Rx descriptors, whereas Linux guests (Virtio PMD & >> virtio-net kernel driver) use indirect only for Tx. >> I'll implement indirect support for the Rx path in vhost lib, but the >> change will be too big for -rc release. >> I propose in the mean time to disable INDIRECT_DESC feature in vhost >> lib, we can still enable it locally for testing. >> >> Yuanhan, is it ok for you? > > That's okay. I'll send a patch to disable it then. > >> >>> Has anyone already tested Windows guest with vhost-net, which also has >>> indirect descs support? >> >> I tested and confirm it works with vhost-net. > > I'm a bit confused then. IIRC, vhost-net also doesn't support indirect > for Rx path, right? No, it does support it actually. I thought it didn't support too, I misread the Kernel implementation of vhost-net and virtio-net. Acutally, virtio-net makes use of indirect in Rx path when mergeable buffers is disabled. The confusion certainly comes from me, sorry about that. Maxime