On Wed, 7 Sep 2016 19:57:19 +0300 Saeed Mahameed <sae...@dev.mellanox.co.il> wrote: > On Wed, Sep 7, 2016 at 6:32 PM, Eric Dumazet <eric.duma...@gmail.com> wrote: > > On Wed, 2016-09-07 at 18:08 +0300, Saeed Mahameed wrote: > >> On Wed, Sep 7, 2016 at 5:41 PM, Eric Dumazet <eric.duma...@gmail.com> > >> 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
