[ltt-dev] Time in trace passes too slowly

Francis Giraldeau francis.giraldeau at usherbrooke.ca
Tue Apr 12 18:05:34 EDT 2011


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?

Cheer, 

Francis





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