WCET-driven Cache-based Procedure Positioning Optimizations

Procedure Positioning is a well known compiler optimization aiming at the improvement of the instruction cache behavior. A contiguous mapping of procedures calling each other frequently in the memory avoids overlapping of cache lines and thus decreases the number of cache conflict misses. In standard literature, these positioning techniques are guided by execution profile data and focus on an improved average-case performance. We present two novel positioning optimizations driven by worst-case execution time (WCET) information to effectively minimize the program´s worst-case behavior. WCET reductions by 10% on average are achieved. Moreover, a combination of positioning and the WCET-driven Procedure Cloning optimization proposed in [14] is presented improving the WCET analysis by 36% on average.