Re: [Xenomai-core] Port to stmp3xxx (arm based)

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 09/18/2011 04:43 PM, Bertold Van den Bergh wrote:
> Hello,
> 
> Thanks for the reply. The timer register has the following layout: bit
> 0-15: reload, bit 16-31: counter. Thats why I put 0xFFFF0000. Looking
> at the code this cannot work so I added an extra field to indicate the
> shift after applying the mask.

You should really upgrade your I-pipe tree to a more recent one, where
the support for tsc emulation was factored. You would add the new case
to the tsc implementations in kernel-space, and nowhere else. When you
are done, please send a patch.

> 
> Now the userspace latency test prorgam gives valid latencies, sadly
> it's still -1ms to 3ms latency.
> 
> How should I proceed troubleshooting this?
> Looking at the ipipe trace it looks the task is brought op quite fast
> after the interrupt fires so I think it is set at the wrong time, I'm
> going to look into this.

The I-pipe tracer has a trace point at the point where the timer was
supposed to tick.

-- 
                                                                Gilles.