Lightning BOLT: powerful, fast, and scalable binary optimization

Abstract

Profile-guided binary optimization has proved to be an important technology to achieve peak performance, particularly for large-scale binaries that are typical for data-center applications. By applying the profile data at the same representation where sampling-based profiling is collected, binary optimizers can provide double-digit speedups over binaries compiled with profile-guided optimizations using similarly collected profile data. The main blocker for adoption of binary optimizers in practice is the overhead that they add to the already long and demanding build pipelines used for producing highly optimized binaries, which already include aggressive compiler optimizations guided by profile data and also link-time optimizations. This paper addresses the overheads of binary optimizers in the context of BOLT, a modern and powerful open-source binary optimizer. More specifically, this paper describes Lightning BOLT, which is an improved version of the BOLT binary optimizer that drastically reduces BOLT’s processing time and memory requirements, while preserving BOLT’s effectiveness in improving the final binary’s performance. Using a set of real-world data-center and open-source applications, we show that Lightning BOLT speeds up BOLT’s processing by an average of 4.71× and reduces BOLT’s memory consumption by 70.5% on average. Furthermore, Lightning BOLT also provides an adjustable mechanism to further reduce BOLT’s overheads at the cost of some lost performance for the final binary.