Re: Ethernet bridge performance

[Felix Radensky <felix@xxxxxxxxx>]

Thanks for your help, Ben. What is skb-recycle patch
and where can I find it ?

Felix.

Ben Greear wrote:

> Felix Radensky wrote:
>
> > Hi,
> >
> > I'm evaluating a performance of a dual port ethernet bridge, and the
> > results are a bit disappointing. I would appreciate any hints on 
> > improving
> > the results.
>
> > c01a13ac 7983     12.5065     eth_type_trans
> > c01a1590 7629     11.9519     qdisc_restart
> > c0197720 7365     11.5383     skb_release_data
> > c010c170 5962      9.3403     do_gettimeofday
>
> If that do_gettimeofday is happening in the skb rx code, then
> you could gain ~10% by disabling it somehow..as it should not
> matter for a bridge.  I bet Robert's skb-recycle patch would
> help here too, especially if you allowed the NICs to save up a large
> number of skbs so that alloc was less likely to fail.
>
> Btw, I've considered saving, say, 10k skbs on a list in my module,
> allocated by GFP_KERNEL at module load time, and using them when
> GFP_ATOMIC skb_alloc fails in the IRQ handling portion of the code....
>
> Anyone think that's a good idea? :)
>
> Ben