From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [virtio-dev] packed ring layout proposal - todo list Date: Wed, 1 Mar 2017 03:07:29 +0200 Message-ID: <20170301030235-mutt-send-email-mst@kernel.org> References: <20160915223915.qjlnlvf2w7u37bu3@redhat.com> <20170222054336-mutt-send-email-mst@kernel.org> <20170228042943.GH18844@yliu-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20170228042943.GH18844@yliu-dev.sh.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Yuanhan Liu Cc: virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On Tue, Feb 28, 2017 at 12:29:43PM +0800, Yuanhan Liu wrote: > Hi Michael, > > Again, as usual, sorry for being late :/ > > On Wed, Feb 22, 2017 at 06:27:11AM +0200, Michael S. Tsirkin wrote: > > Stage 2: prototype guest/host drivers > > > > At this stage we need real guest and host drivers > > to be able to test real life performance. > > I suggest dpdk drivers + munimal hack in qemu to > > pass features around. > > > > I have already done that in last Nov. I made a very rough (yet hacky) > version (only with Tx path) in one day while companying my wife in > hospital. Any performance data? > If someone are interested in, I could share the code soon. I could > even cleanup the code a bit if necessary. Especially if you don't have time to benchmark, I think sharing it might help. > > Tasks: > > > > - implement vhost-user support in dpdk > > - implement virtio support in dpdk > > - implement minimal stub in qemu > > I didn't hack the QEMU, instead, I hacked the DPDK virtio-user, yet > another virtio-net emulation. It's simpler and quicker for me. Sure, I merely meant a stub for negotiating new feature bits between host and guest. But I guess an environment set the same way in host and guest would serve too. > And here is my plan on virtio 1.1: > > - Look deeper inside the virtio net performance issues (WIP) > > It's basically a job about digging the DPDK vhost/virtio code > deeper, something like how exactly the cache acts while Tx/Rx > pkts, what can be optimized by implementation, and what could > be improved with the help of spec extension. > > Please note that I often got interrupted on this task: it didn't > go smooth as I would have expected. > > > - Try to accelerate vhost/virtio with vector instructions. That's interesting. What kind of optimizations would you say do vector instructions enable, and why? > Something I will look into when above item is done. Currently, > I thought of two items may help the vector implementation: > > * what kind of vring and desc layout could make the vector > implementation easier. > > * what kind of hint we need from virtio spec for (dynamically) > enabling the vector path. > > Besides that, I don't have too much clue yet. > > --yliu