Traceview maximum record time?

I am using Debug.startMethodTracing and Debug.stopMethodTracing to optimize a piece of code that takes about 30 sec to execute but when I open the trace file with trace view it only shows me about 6.5 secondes of trace data.

Any clues ?

The function startMethodTracing by default only logs 8MB of trace data. To get a longer trace, set the second parameter to the maximum trace size you want it to record (in bytes).

startMethodTracing("mytrace", 100000000);

The buffer is limited by the device ram. You cannot specify a too big buffer when calling Debug.startMethodTracing.