Gilles,

>> I am running 2.6.19 + adeos-ipipe-2.6.19-arm-1.6-02.patch + xenomai-svn-2007-02-22
>> on an AT91RM9200 (160MHz/80MHz).
>>
>> When starting "latency -p 200" it runs for a while printing
>>
>> RTT|  00:05:37  (periodic user-mode task, 200 us period, priority 99)
>> RTH|-----lat min|-----lat avg|-----lat max|-overrun|----lat best|---lat worst
>> RTD|      11.200|     139.200|     236.800|       1|      10.800|     280.800
>>
>> but then hangs. The timer LED stops blinking. No "soft lockup detected" appears.
> 
> The only explanation I have is that the period is too small. I do not
> observe the same behaviour with latency -p 1000. Note that setting the
> period to a value comparable to the latency is not considered a normal
> use of Xenomai. 

Sure but I would still not expect the system to hang!
As I said missing a deadline is bad but ok.
But hanging the whole system is not quite ok.

>> Using a BDI200 it looks like that in kernel/sched.c:schedule() he is returning
>> in the lines
>>
>> #ifdef CONFIG_IPIPE
>>         if (unlikely(!ipipe_root_domain_p))
>>                 return;
>> #endif /* CONFIG_IPIPE */
>>
>> When stepping trough I only see him getting into schedule() but leaving
>> it in the above lines and in include/linux/proc_fs.h:proc_net_fops_create() ...
> 
> Ok. Thanks for pointing this out. That is interesting, but not very
> informative. It would be interesting if you could get the full
> backtrace. What would be also interesting would be to set a break point
> on the timer interrupt handler and to follow what happens from timer
> interrupt to timer interrupt.

I tried! Attached the patch I used. Since teh scheduler hangs I can't use normal printk(), right?

*ipipe_current_domain != ipipe_root_domain !
*ipipe_current_domain = c01fc2c0
*ipipe_root_domain    = c01af2c0

But I don't get the output of __backtrace()!

my_printk() works with __backtrace(). The dump of a soft lockup works.


Steven