Escape from escape analysis of golang

Abstract

Escape analysis is widely used to determine the scope of variables, and is an effective way to optimize memory usage. However, the escape analysis algorithm can hardly reach 100% accurate, mistakes of which can lead to a waste of heap memory. It is challenging to ensure the correctness of programs for memory optimization. In this paper, we propose an escape analysis optimization approach for Go programming language (Golang), aiming to save heap memory usage of programs. First, we compile the source code to capture information of escaped variables. Then, we change the code so that some of these variables can bypass Golang's escape analysis mechanism, thereby saving heap memory usage and reducing the pressure of memory garbage collection. Next, we present a verification method to validate the correctness of programs, and evaluate the effect of memory optimization. We implement the approach to an automatic tool and make it open-source1. For evaluation, we apply our approach to 10 open-source projects. For the optimized Golang code, the heap allocation is reduced by 8.88% in average, and the heap usage is reduced by 8.78% in average. Time consumption is reduced by 9.48% in average, while the cumulative time of GC pause is reduced by 5.64% in average. We also apply our approach to 16 industrial projects in Bytedance Technology. Our approach successfully finds 452 optimized cases which are confirmed by developers.