Re: [PATCH] RCU for low latency (experimental)

Dipankar Sarma
2004-03-29T12:31:19Z

On Mon, Mar 29, 2004 at 12:43:11PM +0200, Takashi Iwai wrote:
> At Sun, 28 Mar 2004 19:28:41 +0200,
> I wrote:
> >
> > > > anyway, i confirmed that with the original krcud patch the latency
> > > > with dcache flood can be eliminated.
> > >
> > > Does the throttle-rcu patch also help eliminate dcache flood ? You
> > > can try by just changing count >= rcumaxbatch to ++count > rcumaxbatch.
> >
> > i'll try it later.
>
> the throttle-rcu patch does work indeed well even without preemption.
> i've tested maxbatch=16 and plugticks=0. in the older version, there
> was 20ms long latency, while in the patched version, no measurable
> latency more than 1ms.

Thanks for the measurements. throttle-rcu may eventually be the way
to go, but I would wait until we have sorted out several other problems
like route cache DoS testing that we are looking at currently.

Thanks
Dipankar