要改善系統效能，首先必須有個量測系統效能的工具，本篇紀錄在 ARM in Linux 如何手動編譯 perf 。
摘錄網路上對 perf 的說明如下：
perf (sometimes called "Perf Events"or perf tools, originally "Performance Counters for Linux", PCL) is a performance analyzing tool in Linux, available from Linux kernel version 2.6.31.
it can instrument CPU performance counters, tracepoints, kprobes, and uprobes (dynamic tracing). It is capable of lightweight profiling. It is also included in the Linux kernel, under tools/perf, and is frequently updated and enhanced.
perf 的使用範例可以參考 IBM提供的文章，
