Re: preemption and rwsems (was: Re: missing madvise functionality)

Andrew Morton
2007-04-06T19:30:09Z

On Fri, 6 Apr 2007 11:08:22 +0200
Ingo Molnar <mingo@elte.hu> wrote:

> * Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > > getting a good trace of it is easy: pick up the latest -rt kernel
> > > from:
> > >
> > > http://redhat.com/~mingo/realtime-preempt/
> > >
> > > enable EVENT_TRACING in that kernel, run the workload and do:
> > >
> > > scripts/trace-it > to-ingo.txt
> > >
> > > and send me the output.
> >
> > Did that - no output was generated. config at
> > http://userweb.kernel.org/~akpm/config-akpm2.txt
>
> sorry, i forgot to mention that you should turn off
> CONFIG_WAKEUP_TIMING.
>
> i've attached an updated version of trace-it.c, which will turn this off
> itself, using a sysctl. I also made WAKEUP_TIMING default-off.

ok. http://userweb.kernel.org/~akpm/to-ingo.txt is the trace of

taskset -c 0 ./jakubs-test-app

while the system was doing the 150,000 context switches/sec.

It isn't very interesting.