[Xenomai-help] NMI watchdog: Loading of xeno_native leads to reboot of PC

["M. Koehrer" <mathias_koehrer@domain.hid>]

Hi!

Before digging deeper into the issue I have mailed yesterday (see below), I have to solve and
to understand the NMI watchdog feature.
I have enabled the NMI watchdog in the kernel configuration and set the time value to 100 now (100us).
Also, I passed the nmi_watchdog=1 kernel parameter to GRUB.
In dmesg's output I see the line:
Testing NMI watchdog ... OK.
 
The Xenomai functionality is compiled as modules (as far as it is possible).

Now, I do a 
modprobe xeno_nucleus
This looks fine.

Now, I do a 
modprobe xeno_native
to load the native skin (I need it for my application to run).
Then the PC reboots directly.
This means I have no chance to  start my application as the PC reboots before
I can start it...

I have the impression that some important thing is missing in my test.
The xeno timer is not started after modprobe xenu_nucleus
The contents of /proc/timer is:
status=off:setup=120:tickval=0:jiffies=0

Could this be a reason for the behaviour?
Can I start the timer before loading xeno_native to avoid the NMIs?

Thanks for all help on this topic as without this feature it seems to be impossible
to detect the bug/issue with a freezing system with the latest Xenomai/rtnet and 
kernel 2.6.19.1. (see https://mail.gna.org/public/xenomai-help/2006-12/msg00109.html)

Regards

Mathias



----- Original Nachricht ----
Von:     Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
An:      "M. Koehrer" <mathias_koehrer@domain.hid>
Datum:   18.12.2006 16:32
Betreff: Re: Aw: Re: Aw: Re: [RTnet-users] [Xenomai-help] rtnet / Xenomai:
 Kernel

> M. Koehrer wrote:
> > O.k,
> > 
> > I tried once more with the  NMI watchdog stuff.
> > However, it looks as if I do not understand the NMI watchdog correctly...
> > I passed nmi_watchdog=1 as kernel parameter.
> > Now, the NMI watchdog seems to be o.k.
> > I have set the kernel parameter "NMI watchdog latency threshold (us)" to
> 1000000 (1 second).
> > Now I do a modprobe xeno_nucleus.
> > This is o.k.
> > Then I do a modprobe xeno_native.
> > This leads to a watchdog NMI on the console after 1s.
> > "NMI watchdog detected timer latency above 100000us"
> > CPU 1
> > EIP is at mwait_idle 0x23/0x37
> > 
> > When I compile the Xenomai functionality directly into the kernel (no
> modules), I never reach
> > the login prompt at my PC as the NMI watchdog from above came first...
> > 
> > Well, somehow the NMI stuff seems to work. However, I am not able to start
> my application
> > as my systems gets the NMI before I have the chance to start the
> application...
> > What is wrong here? I think, I miss one piece in the puzzle...
> > 
> > Thanks for any support on that strange behaviour.
> 
> 1 second is probably way to much and overflow a 32 bits value when
> converted to a processor ticks count. The defaults of 100 us is more
> reasonable.
> 
> -- 
>                                                  Gilles Chanteperdrix
> 

-- 
Mathias Koehrer
mathias_koehrer@domain.hid


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