Re: More latency regressions with 2.6.11-rc4-RT-V0.7.39-02

Lee Revell
2005-02-24T02:25:44Z

On Thu, 2005-02-24 at 12:29 +1100, Nick Piggin wrote:
> Lee Revell wrote:
> >
> > IIRC last time I really tested this a few months ago, the worst case
> > latency on that machine was about 150us. Currently its 422us from the
> > same clear_page_range code path.
> >
> Well it should be pretty trivial to add a break in there.
> I don't think it can get into 2.6.11 at this point though,
> so we'll revisit this for 2.6.12 if the clear_page_range
> optimisations don't get anywhere.
>

Agreed, it would be much better to optimize this away than just add a
scheduling point. It seems like we could do this lazily.

IMHO it's not critical that these latency fixes be merged until the VP
feature gets merged, until then people will be using Ingo's patches
anyway.

Lee