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

[Andrew Morton]

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

> * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> 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.
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