Re: [Xenomai-help] latency problems

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

Nadym Salem schrieb:
> On Thu, August 16, 2007 16:31, Gilles Chanteperdrix wrote:
>> On 8/16/07, Nadym Salem <Kaiman@domain.hid> wrote:
>>> On Thu, August 16, 2007 16:01, Gilles Chanteperdrix wrote:
>>>> Aha, this probably means that your chipset is not supporte, could you
>>>> run lspci and send us the output ?
>>> it is attached.
>> Could you try to apply the attached patch to xenomai sources ? You
>> will then have to recompile your xenomai-patched kernel.
> 
> Hmm, I have a new (quite old) machine now and installed Xenomai 2.3.3,
> having the same problem as before. The SMI workaround doesn't appear in
> the kernel log at all. Last time you gave me a "patch" for smi.c after
> which the system at least tried to start the smi workaround. Is there
> another possibility like that for my other machine ? I attached the output
> of lspci.
> 
> tx in advance,
> 
> greets, Nadym
> 
> PS: Could it be, that this machine doesn't have SMIs at all ?

For sure, but there can also be other hardware-related latency killers. 
So far the SMI workaround only deals with Intel chipsets (because there 
are known knobs thanks to the chipset manual).

I can't join this party for the next days, but I would like to throw in 
the question if you already tried to analyse the latency spot with the 
I-pipe tracer (see Xenomai wiki). That may either underline that it is 
outside the software's scope (arbitrary delays in unrelated kernel 
functions) or point to a potential (but less likely) software issue.

Jan

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