Jan Kiszka wrote:
> Sebastian Smolorz wrote:
> > However, there is one disturbing issue. When I execute
> >
> > dd if=/dev/zero of=/dev/null
> >
> > and the latency test in userspace with a period not less than 150 us the
> > worst case latency is about 220 us. But when I start latency with -p 100
> > I get a softlock like the one attached. I guess this is the same problem
> > as Detlef Vollmann described in [2]. So I think it's time for a big fat
> > ARM-specific warning in the troubleshooting file and perhaps a
> > modification of the testsuite so that if being compiled for ARM the
> > default sample periods are greater than the 100 us now.
> Something is preventing the watchdog kthread from being executed for
> more than 10 s. Maybe this is just a sign that the systems is hopelessly
> overloaded (what are average latencies?).

They are 120-130 us.

> Maybe it is a real IRQ or 
> scheduling issue in Linux caused by I-pipe. Maybe it is time to port the
> I-pipe tracer... ;)

With the latest Adeos upgrade for ARM the I-pipe tracer was integrated, wasn't 
it? I was already taking its usage into account.


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