From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer via iovisor-dev Subject: Re: [PATCH RFC 11/11] net/mlx5e: XDP TX xmit more Date: Wed, 7 Sep 2016 20:22:34 +0200 Message-ID: <20160907202234.55e18ef3@redhat.com> References: <1473252152-11379-1-git-send-email-saeedm@mellanox.com> <1473252152-11379-12-git-send-email-saeedm@mellanox.com> <1473259302.10725.31.camel@edumazet-glaptop3.roam.corp.google.com> <1473262379.10725.42.camel@edumazet-glaptop3.roam.corp.google.com> Reply-To: Jesper Dangaard Brouer Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , Linux Netdev List , iovisor-dev , Jamal Hadi Salim , Saeed Mahameed , Eric Dumazet , Tom Herbert To: Saeed Mahameed Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iovisor-dev-bounces-9jONkmmOlFHEE9lA1F8Ukti2O/JbrIOy@public.gmane.org Errors-To: iovisor-dev-bounces-9jONkmmOlFHEE9lA1F8Ukti2O/JbrIOy@public.gmane.org List-Id: netdev.vger.kernel.org On Wed, 7 Sep 2016 19:57:19 +0300 Saeed Mahameed wrote: > On Wed, Sep 7, 2016 at 6:32 PM, Eric Dumazet wrote: > > On Wed, 2016-09-07 at 18:08 +0300, Saeed Mahameed wrote: > >> On Wed, Sep 7, 2016 at 5:41 PM, Eric Dumazet wrote: > >> > On Wed, 2016-09-07 at 15:42 +0300, Saeed Mahameed wrote: [...] > > > > Only if a qdisc is present and pressure is high enough. > > > > But in a forwarding setup, we likely receive at a lower rate than the > > NIC can transmit. Yes, I can confirm this happens in my experiments. > > > > Jesper has a similar Idea to make the qdisc think it is under > pressure, when the device TX ring is idle most of the time, i think > his idea can come in handy here. I am not fully involved in the > details, maybe he can elaborate more. > > But if it works, it will be transparent to napi, and xmit more will > happen by design. Yes. I have some ideas around getting more bulking going from the qdisc layer, by having the drivers provide some feedback to the qdisc layer indicating xmit_more should be possible. This will be a topic at the Network Performance Workshop[1] at NetDev 1.2, I have will hopefully challenge people to come up with a good solution ;-) -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer [1] http://netdevconf.org/1.2/session.html?jesper-performance-workshop