Re: [Xenomai-core] latencys drifting into negative (Xenomai 2.4.2/2.4.3)

[Tomas Kalibera <kalibera@domain.hid>]

Hi,

I don't have the answer, but just to feed my curiosity, do you know what 
would happen if you run the benchmarks much longer ? I can imagine that 
it would either stabilize on some value, or, it might start again from a 
large value at the beginning..

Tomas

Cornelius Köpp wrote:
> Hello,
> I run the latency test from testsuite on several hard and software configurations. Running on Xenomai 2.4.2, Linux 2.6.24 the results shows a "strange" behavior: In Kernel mode (-t1) the latencys constantly linear decrease. See attached plot 'drifting_latencys_in_kernelmode.png' of latency test running 48h on Pentium3 700. This effect could be reproduced, even on other hardware (Pentium-M 1400). The usermode (-t0) did not show a drifting, but is influenced by a test ran in kernelmode before.
>
> I talked with Sebastian Smolorz about this and he builds his own independent kernel-config to check. He got the same drifting-effect with Xenomai 2.4.2 and Xenomai 2.4.3 running latency over several hours. His kernel-config ist attached as 'config-2.6.24-xenomai-2.4.3__ssm'.
>
> Our kernel-configs are both based on a config used with Xenomai 2.3.4 and Linux 2.6.20.15 without any drifting effects.
>
> Bad luck with the config?
>
>
> Thanks in advance,
>
> Cornelius Köpp
>   
>
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