Introduction

This document describes how to install the automatic feedback-directed optimization tool (A-FOT) on a Kunpeng server running the openEuler OS, and provides operation guidance for automatic feedback-directed optimization (FDO) and solutions to faults that may occur during automatic FDO.

The Kunpeng GCC Continuous Feature Guided Optimization (CFGO) feature is available for multi-modal objects (source code, assembly code, and binary) and in multiple lifecycle phases (compile time, link time, and post-link time).

The GCC FDO component is a plugin of the GCC compiler and can be manually executed. A-FOT is designed to enable automatic FDO operations (including sampling, analysis, and optimization) with fewer configurations, which improves the usability of the GCC CFGO feature. With A-FOT, automatic FDO can be implemented. The GCC FDO component collects information including the program execution path, number of function calls, and variable usage without changing program capabilities, and sends the information to the compiler. Based on the information, the compiler performs refined code optimization to build a target program with better performance. Compiler optimization is a common technique to improve software performance.

This feature can improve the overall database performance in TPC-C tests by 10% on servers and that in sysbench tests by 30% (based on optimal results) in 8 vCPUs, 32GB memory specifications.