Re: [patch] voluntary-preempt-2.6.8.1-P8

Lee Revell
2004-08-24T17:17:41Z

On Tue, 2004-08-24 at 09:48, K.R. Foley wrote:
> Lee Revell wrote:
> > On Tue, 2004-08-24 at 01:41, Ingo Molnar wrote:
> >
> >>* Lee Revell <rlrevell@joe-job.com> wrote:
> >>
> >>
> >>>> - reduce netdev_max_backlog to 8 (Mark H Johnson)
> >>>
> >>>On my system this setting has absolutely no effect on the skb related
> >>>latencies. [...]
> >>
> >>it has an effect on input queue length. Output queue lengths can be
> >>reduced via 'ifconfig eth0 txqueuelen 8'.
> >>
> >
> >
> > OK. With both of these set to 4, the largest latency I was able to
> > generate by ping flooding was 253 usecs.
> >
>
> Even with both of these set to 4, I still get similar results ~647 usec :(
>

I am able to generate a 1012 usec latency by flood pinging the broadcast
address. These are pretty pathological cases, but if we are going for
bounded latency it seems like they should be addressed.

Lee