For some time now my builds of python 3.2 on x86_64 platform in SuSE OBS are failing depending on the phase of the moon. The spec file for the python3-base package uses 'make profile-opt' command to build and Makefile.pre.in uses pybench.py for profile guided optimization. The pybench.py fails sometimes with the '* Internal Error (use --debug to display the traceback)' error. Adding --debug gives 'calibration setup did not work' i.e. some of the self.overhead_times values in the Test.calibrate_test method became negative. It happens for the  NestedForLoops test. The source inspection shows that most probably it was forgotten to divide by CALIBRATION_LOOPS when calculating prep_times. The patch against current head is attached, it solves the problem.