From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [RFC PATCH net-next 0/3] virtio_net: add aRFS support Date: Thu, 23 Jan 2014 16:26:09 +0200 Message-ID: <20140123142609.GD21572@redhat.com> References: <1389795654-28381-1-git-send-email-zwu.kernel@gmail.com> <52D75EA5.1050000@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jason Wang , Linux Netdev List , Tom Herbert , Eric Dumazet , "David S. Miller" , Zhi Yong Wu , Stefan Hajnoczi , Rusty Russell To: Zhi Yong Wu Return-path: Received: from mx1.redhat.com ([209.132.183.28]:41110 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932095AbaAWOVb (ORCPT ); Thu, 23 Jan 2014 09:21:31 -0500 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Jan 16, 2014 at 04:48:43PM +0800, Zhi Yong Wu wrote: > On Thu, Jan 16, 2014 at 12:23 PM, Jason Wang wrote: > > On 01/15/2014 10:20 PM, Zhi Yong Wu wrote: > >> > >> From: Zhi Yong Wu > >> > >> HI, folks > >> > >> The patchset is trying to integrate aRFS support to virtio_net. In this > >> case, > >> aRFS will be used to select the RX queue. To make sure that it's going > >> ahead > >> in the correct direction, although it is still one RFC and isn't tested, > >> it's > >> post out ASAP. Any comment are appreciated, thanks. > >> > >> If anyone is interested in playing with it, you can get this patchset from > >> my > >> dev git on github: > >> git://github.com/wuzhy/kernel.git virtnet_rfs > >> > >> Zhi Yong Wu (3): > >> virtio_pci: Introduce one new config api vp_get_vq_irq() > >> virtio_net: Introduce one dummy function virtnet_filter_rfs() > >> virtio-net: Add accelerated RFS support > >> > >> drivers/net/virtio_net.c | 67 > >> ++++++++++++++++++++++++++++++++++++++++- > >> drivers/virtio/virtio_pci.c | 11 +++++++ > >> include/linux/virtio_config.h | 12 +++++++ > >> 3 files changed, 89 insertions(+), 1 deletions(-) > >> > > > > Please run get_maintainter.pl before sending the patch. You'd better at > > least cc virtio maintainer/list for this. > Is this one must for virtio stuff? See Documentation/SubmittingPatches > > > > The core aRFS method is a noop in this RFC which make this series no much > > sense to discuss. You should at least mention the big picture here in the > > cover letter. I suggest you should post a RFC which can run and has expected > > result or you can just raise a thread for the design discussion. > Yes, it currently miss some important stuff as i said in another mail > of this series. > > > > > And this method has been discussed before, you can search "[net-next RFC > > PATCH 5/5] virtio-net: flow director support" in netdev archive for a very > > old prototype implemented by me. It can work and looks like most of this RFC > > have already done there. > ah? Can you let me know the result of your discussion? Will checked > it, thanks for your pointer. > > > > A basic question is whether or not we need this, not all the mq cards use > > aRFS (see ixgbe ATR). And whether or not it can bring extra overheads? For > > virtio, we want to reduce the vmexits as much as possible but this aRFS > Good question, i also have concern about this, and don't know if Tom > has good explanation. > > seems introduce a lot of more of this. Making a complex interfaces just for > > an virtual device may not be good, simple method may works for most of the > > cases. > > > > We really should consider to offload this to real nic. VMDq and L2 > > forwarding offload may help in this case. > > By the way, Stefan, can you let us know your concerns here? as we > talked in irc channel. :) > > > -- > Regards, > > Zhi Yong Wu