Subject: Re: [PATCH bpf-next v4 1/2] bpf, xdp: make bpf_redirect_map() a map operation

From: Jesper Dangaard Brouer <[email-masked]>
Date: Fri, 26 Feb 2021 15:28:27 +0100

On Fri, 26 Feb 2021 13:26:22 +0100
Toke Høiland-Jørgensen <[email-masked]> wrote:

> Björn Töpel <[email-masked]> writes:
> 
> > On 2021-02-26 12:40, Björn Töpel wrote:  
> >> On 2021-02-26 12:37, Toke Høiland-Jørgensen wrote:  
> >
> > [...]
> >  
> >>>
> >>> (That last paragraph above is why I asked if you updated the performance
> >>> numbers in the cover letter; removing an additional function call should
> >>> affect those, right?)
> >>>  
> >> 
> >> Yeah, it should. Let me spend some more time benchmarking on the DEVMAP
> >> scenario.
> >>  
> >
> > I did a re-measure using samples/xdp_redirect_map.
> >
> > The setup is 64B packets blasted to an i40e. As a baseline,
> >
> >    # xdp_rxq_info --dev ens801f1 --action XDP_DROP
> >
> > gives 24.8 Mpps.
> >
> >
> > Now, xdp_redirect_map. Same NIC, two ports, receive from port A,
> > redirect to port B:
> >
> > baseline:    14.3 Mpps
> > this series: 15.4 Mpps
> >
> > which is almost 8%!  
> 
> Or 5 ns difference:
> 
> 10**9/(14.3*10**6) - 10**9/(15.4*10**6)
> 4.995004995005004
> 
> Nice :)

Yes, this is a very significant improvement at this zoom-in
benchmarking level :-)

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer