A method for scheduling execution of a work unit in a data processing system comprises assigning to the work unit an expected execution duration; executing the work unit determining an actual execution duration of the work unit; determining a difference between the actual execution duration and the expected duration; and conditionally adjusting the expected execution duration assigned to the work unit based on the measured actual execution duration, wherein the conditionally adjusting includes preventing the adjustment of the expected execution duration in case said difference exceeds a predetermined threshold. The method further includes associating to the work unit a parameter having a prescribed value adapted to provide an indication of unconditional adjustment of the expected execution duration: in case said parameter takes the prescribed value, the expected duration assigned with the work unit based on the measured actual execution duration even if the difference in durations exceeds the predetermined threshold.