Automatic Recommendation of Compiler Options

While many optimizations can yield substantial performance improvements under the right circumstances, these same optimizations may cause significant performance degradations or cause other problems under the wrong circumstances. The problem of determining which optimizations to apply is generally relegated to the over-burdened compiler user, who must wade through a daunting set of cryptic documentation to find the right set of compiler switches to use to achieve good performance. In this paper, we address the question of whether this process can be automated. To do so, we developed an automatic options recommender called Dr. Options which attempts to recommend the best options to achieve high performance when using Hewlett-Packard's PA-RISC optimizing compilers. We have found that Dr. Options recommendations can be substantially better than those which typical users might come up with on their own. Moreover, Dr. Options has proven itself, at the very least, to be a useful consultant for even our most expert in house performance analysts. In a few cases, Dr. Options even beat the experts!