• https://sourceware.org/binutils/docs/gprof/

• https://hpc.llnl.gov/software/development-environment-software/gprof

• https://stackoverflow.com/questions/9608949/gprof-time-spent-in-particular-lines-of-code

• Linux性能评测工具之一：gprof篇

• 使用 GNU profiler 来提高代码运行速度

• gprof Quick-Start Guide

• How exactly does gprof work?

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• Tutorial: Using GNU Profiling (gprof) with ARM Cortex-M

gprof: Call Counting and PC Sampling

• Function Call Counting: it counts for every instrumented function, how many times the function is called and from where. gcc inserts at the beginning of each instrumented function a call to a special library function to count the calls. This creates ‘Arcs’: information about who is calling what, how many times. Think about directed edges in a graph. Counting is done with _mcount() or in the case of GNU for ARM with __gnu_mcount_nc().
• Program Counter Sampling: at a period time, the current PC (Program Counter) gets sampled, creating a histogram of PC over addresses. This is typically done with a profile() function.

Memory Requirements for Arcs and Histogram

Program Flow

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Trouble-shooting

no gmon.out

• 链接参数要加-pg
• gmon.out is not written after compiling with gcc -pg -g
• gprof问题没有生成gmon.out
• 程序不产生gmon.out的原因

wrong function name

• wrong gprof results with gcc -Ofast -pg