Re: [PATCH] latency-profiling

[Roger Larsson]

On Thursdayen den 20 September 2001 21.55, george anzinger wrote:
> Roger Larsson wrote:
> > Hi,
> >
> > I ported my old latency-profiling patch to 2.4.10-pre10 with
> > the reschedulable kernel patch. (I have not checked that it is
> > preemption safe itself...)
> >
> > This patch works a little different from Robert Loves.
> > Since it samples the execution location at ticks.
> > It is possible to instrument an ordinary kernel too...
>
> It gives experienced latencies rather than potential latencies, but more
> important from the developer/maintainers point of view, "Robert Loves"
> patch provides information on the bad guys, i.e. the reason for the long
> latency, which, hopefully, will allow them to be addressed by competent
> maintainers.
>

Yes, but my technique can be applied to any kernel. It does not require
an preemptible kernel...

I.e. measures time from the moment a reschedulation was reqired to it
is actually done - independent of how it is done...

And if you run something that needs periodic reshedules you will detect
actual problems.

And thus it can be used as a bench, it is hard to describe skips in music,
textual data is easier to send by mail...

But I agree that Roberts is better to find the critical ones!

/RogerL

-- 
Roger Larsson
Skellefteċ
Sweden