FuncyTuner

The de facto compilation model for production software compiles all modules of a target program with a single set of compilation flags, typically 02 or 03. Such a per-program compilation strategy may yield sub-optimal executables since programs often have multiple hot loops with diverse code structures and may be better optimized with a per-region compilation model that assembles an optimized executable by combining the best per-region code variants. In this paper, we demonstrate that a naïve greedy approach to per-region compilation often degrades performance in comparison to the 03 baseline. To overcome this problem, we contribute a novel per-loop compilation framework, FuncyTuner, which employs lightweight profiling to collect per-loop timing information, and then utilizes a space-focusing technique to construct a performant executable. Experimental results show that FuncyTuner can reliably improve performance of modern scientific applications on several multi-core architectures by 9.2% to 12.3% and 4.5% to 10.7%(geometric mean, up to 22% on certain program) in comparison to the 03 baseline and prior work, respectively.