[ltt-dev] Time in trace passes too slowly
Mathieu Desnoyers
compudj at krystal.dyndns.org
Wed Apr 13 11:38:56 EDT 2011
* Francis Giraldeau (francis.giraldeau at usherbrooke.ca) wrote:
> Hi,
>
> In a trace, the time difference between two timestamps doesn't match the
> time it should have elapsed. For example, when measuring the duration of
> "sleep 1" in the trace, 0.358s is obtained. The real duration of the
> sleep is indeed 1 second. The error seems proportional to a constant
> factor.
>
> I get this behavior on a 32 bits Ubuntu with 2.6.35-24-lttng from the
> PPA. I'm running the same version of kernel but configured with 64 bits
> and durations are correct.
>
> I put a sample trace here:
>
> http://secretaire.dorsal.polymtl.ca/~fgiraldeau/sleep-1x-1sec.tar.gz
>
> Seems a bug to me, or maybe I'm doing something wrong?
What is the output of your /proc/cpuinfo ?
Can you paste your dmesg ?
Thanks,
Mathieu
>
> Cheer,
>
> Francis
>
>
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--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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