Subject: Re: [PATCH v10 12/12] bpf: add sample for xdp forwarding and rewrite

From: Jesper Dangaard Brouer <[email-masked]>
Date: Wed, 27 Jul 2016 20:25:48 +0200

On Tue, 19 Jul 2016 15:05:37 -0700
Alexei Starovoitov <[email-masked]> wrote:

> On Tue, Jul 19, 2016 at 12:16:57PM -0700, Brenden Blanco wrote:
> > Add a sample that rewrites and forwards packets out on the same
> > interface. Observed single core forwarding performance of ~10Mpps.
> > 
> > Since the mlx4 driver under test recycles every single packet page, the
> > perf output shows almost exclusively just the ring management and bpf
> > program work. Slowdowns are likely occurring due to cache misses.  
> 
> long term we need to resurrect your prefetch patch. sux to leave
> so much performance on the table.

I will do some (more) attempts at getting prefetching working, also in
a way that benefit the normal stack (when I'm back from vacation, and
when net-next opens again).

I think Rana is also looking into this for the mlx5 driver (based on
some patches I send to her).

-- 
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