Collecting Profile Information Using Application Execution Traces for Static Optimizing Binary Translation

Abstract

Static binary optimization is one of the ways to speed up an executable file without source code. This technology is used in the BOLT (Binary Optimization and Layout Tool), which requires a profile with information about taken and information about not predicted transitions for its work, which can be obtained from the LBR (Last Branch Record) hardware queue on the x86 architecture. This information is necessary for the BOLT in order to relocate the code, that reduces the number of misses on the instruction cache and the buffer of associative translation of instructions. As a result of the optimization, it was possible to speed up the work of server applications by 8.0% running on x86 architectures. There are limitations on the use of this optimization on the ARM architecture due to the frequent lack of the ability to obtain profile information using hardware. This article describes the developed methods and tools that allow us to obtain profile information using the application execution route. The process of collecting the trace is implemented using dynamic binary instrumentation. The article describes an algorithm for restoring profile information using a branch predictor model. The implemented BOLT changes for extended ARM architecture support are also described. As a result of the work, it was possible to achieve performance growth targets on synthetic tests and benchmarks.

Keywords

• binary optimization
• simulation
• dynamic binary instrumentation
• profiling
• risc
• bolt
• arm