Re: [Xenomai-help] Xenomai on i7-870

[Jan Kiszka <jan.kiszka@domain.hid>]

On 2011-06-14 13:18, Jakub Nowacki wrote:
> On 06/14/2011 06:58 AM, Jan Kiszka wrote:
>>
>> Do you have the irqbalance daemon running? If yes, disable it and retry.
> 
> Yes I had. Disabling it helped, namely system works now. I just think I
> have a slightly higher latencies. Namely, in the 100 us period the
> average is most of the times about -0.4 us, whereas min and max are
> approx. -2.5 us and 22 us, respectively. They are still quite good but I
> think I had slightly lower, especially the max was around 11 us, for no
> PM. But is not that important for me now.

How long did each of those tests run? And under which load?

> 
>> If it helps, you may also want to try
>>
>> git://git.kiszka.org/ipipe.git queues/2.6.38-x86
>>
>> If that doesn't help, try to disable CONFIG_DMAR (though it should left
>> off by default during boot) and CONFIG_INTR_REMAP.
> 
> They are now both on. Since the kernel works now should I let them be or
> still switch them off?

It will at least prevent you from accidentally using it.

> 
>> Regarding CONFIG_HPET_TIMER: That's not selectable on x86-64. If you
>> have "enough" cores, the kernel will run out of HPET timers and won't
>> select them as clock events. With 8 cores, you should be safe, but
>> better check the kernel boot messages for "hpet" or the state of
>> /proc/timer_list regarding "Clock Event Device" when booting the same
>> kernel without Xenomai support.
> 
> Thanks for clarifying that. BTW my /proc/timer_list says for 'Clock
> Event Device' 'pit' for the first one and 'lapic' for other on both
> ubuntu and ipipe kernel. Hence, looks like no 'hpet' is involved. Also I
> didn't find any 'hpet' messages in the kernel log.
> 
> Since a new Adeos patch has just arrived, I'll give it a try with kernel
> 2.6.38.8 and see how it behaves.

That /should/ make irqbalance work - though I'm not 100% sure, we are
still hunting bugs in our 2.6.35-based kernel here.

> BTW maybe it's a silly question but
> should I rebuild Xenomai each time I install new kernel? Or rephrasing
> it, when should I rebuild Xenomai?

Kernel parts: clear yes, but Xenomai's bits are rebuild automatically
anyway.

User parts: no need unless you changed the Xenomai version (major release).

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux