Introduction

In this practice, the Kunpeng Performance Boundary Analyzer is used to quickly identify performance issues. It is preliminarily identified that hotspot system functions are frequently invoked, indicating a performance bottleneck. Then, the System Profiler is used to analyze the hotspot functions, and a flame graph is used to examine the call stack. The analysis shows that I/O system calls account for a high proportion of execution time. Source code inspection further indicates that this issue is caused by high overhead from frequent read system calls. Next, the memory mapping (mmap) method is used to reduce data copies and system calls, optimizing the large-file read logic and thereby reducing I/O latency and improving program performance.