Background optimization in full system binary translation

Abstract

Binary translation and dynamic optimization are widely used to provide compatibility between legacy and promising upcoming architectures on the level of executable binary codes. Dynamic optimization is one of the key contributors to dynamic binary translation system performance. At the same time it can be a major source of overhead, both in terms of CPU cycles and whole system latency, as long as optimization time is included in the execution time of the application under translation. One of the solutions that allow to eliminate dynamic optimization overhead is to perform optimization simultaneously with the execution, in a separate thread. In the paper we present implementation of this technique in full system dynamic binary translator. For this purpose, an infrastructure for multithreaded execution was implemented in binary translation system. This allowed running dynamic optimization in a separate thread independently of and concurrently with the main thread of execution of binary codes under translation. Depending on the computational resources available, this is achieved whether by interleaving the two threads on a single processor core or by moving optimization thread to an underutilized processor core. In the first case the latency introduced to the system by a computational intensive dynamic optimization is reduced. In the second case overlapping of execution and optimization threads also results in elimination of optimization time from the total execution time of original binary codes.