From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966645AbeBNCri (ORCPT ); Tue, 13 Feb 2018 21:47:38 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56370 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S966497AbeBNCrg (ORCPT ); Tue, 13 Feb 2018 21:47:36 -0500 Date: Wed, 14 Feb 2018 04:47:34 +0200 From: "Michael S. Tsirkin" To: Jason Wang Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, wexu@redhat.com, jfreimann@redhat.com, tiwei.bie@intel.com Subject: Re: [PATCH RFC 0/2] Packed ring for vhost Message-ID: <20180214044634-mutt-send-email-mst@kernel.org> References: <1518575829-1431-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1518575829-1431-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 14, 2018 at 10:37:07AM +0800, Jason Wang wrote: > Hi all: > > This RFC implement a subset of packed ring which was described at > https://github.com/oasis-tcs/virtio-docs/blob/master/virtio-v1.1-packed-wd07.pdf > . The code were tested with pmd implement by Jens at > http://dpdk.org/ml/archives/dev/2018-January/089417.html. Minor > change was needed for pmd codes to kick virtqueue since it assumes a > busy polling backend. > > Test were done between localhost and guest. Testpmd (rxonly) in guest > reports 2.4Mpps. Testpmd (txonly) repots about 2.1Mpps. How does this compare with the split ring design? > It's not a complete implemention, here's what were missed: > > - Device Area > - Driver Area > - Descriptor indirection > - Zerocopy may not be functional > - Migration path is not tested > - Vhost devices except for net > - vIOMMU can not work (mainly because the metadata prefetch is not > implemented). > - See FIXME/TODO in the codes for more details > - No batching or other optimizations were implemented ioeventfd for PIO/mmio/s390. > For a quick prototype, this series open code the tracking of warp > counter and descriptor index at net device. This will be addressed in > the future by: > > - Move get_rx_bufs() from net.c to vhost.c > - Let vhost_get_vq_desc() returns vring_used_elem instad of head id > > With the above, we can hide the internal (at least part of) vring > layout from specific device. > > Please review. > > Thanks > > Jason Wang (2): > virtio: introduce packed ring defines > vhost: packed ring support > > drivers/vhost/net.c | 14 +- > drivers/vhost/vhost.c | 351 ++++++++++++++++++++++++++++++++++--- > drivers/vhost/vhost.h | 6 +- > include/uapi/linux/virtio_config.h | 9 + > include/uapi/linux/virtio_ring.h | 17 ++ > 5 files changed, 369 insertions(+), 28 deletions(-) > > -- > 2.7.4