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commit b8670e905a68bdf721a6efbeaeecabe36ee7bebd Author: yinshengkai <[email protected]> AuthorDate: Thu Oct 10 01:05:23 2024 +0800 docs: add gprof usage documentation Signed-off-by: yinshengkai <[email protected]> g 请为您的变更输入提交说明。以 '#' 开始的行将被忽略，而一个空的提交 --- Documentation/applications/system/gprof/index.rst | 81 +++++++++++++++++++++++ 1 file changed, 81 insertions(+) diff --git a/Documentation/applications/system/gprof/index.rst b/Documentation/applications/system/gprof/index.rst new file mode 100644 index 0000000000..caf82dd198 --- /dev/null +++ b/Documentation/applications/system/gprof/index.rst @@ -0,0 +1,81 @@ +============================= +``gprof`` GNU Profile tool +============================= + +GNU Profile (gprof) is a performance analysis tool that helps developers +identify code bottlenecks and optimize their programs. +It provides detailed information about the execution time and call +frequency of functions within a program. + +gprof can be used to: + +1. Detect performance bottlenecks in your code +2. Identify which functions consume the most execution time +3. Analyze the call graph of your program +4. Help prioritize optimization efforts + +Usage +===== + +Build +----- + +Enable the following configuration in NuttX:: + + CONFIG_SYSTEM_GPROF + +Using in NuttX +-------------- + +1. Start profiling:: + + nsh> gprof start + +2. Stop profiling:: + + nsh> gprof stop + +3. Dump profiling data:: + + nsh> gprof dump /tmp/gmon.out + +Analyzing on Host +----------------- + +1. Pull the profiling data to host:: + + adb pull /tmp/gmon.out ./gmon.out + +2. Analyze the data using gprof tool:: + + The saved file format complies with the standard gprof format. + For detailed instructions on gprof command usage, please refer to the GNU gprof manual: + https://ftp.gnu.org/old-gnu/Manuals/gprof-2.9.1/html_mono/gprof.html + + arm-none-eabi-gprof ./nuttx/nuttx gmon.out -b + + Example output: + + ``` + arm-none-eabi-gprof nuttx/nuttx gmon.out -b + Flat profile: + + Each sample counts as 0.001 seconds. + % cumulative self self total + time seconds seconds calls s/call s/call name + 66.41 3.55 3.55 43 0.08 0.08 sdelay + 33.44 5.34 1.79 44 0.04 0.04 delay + 0.07 5.34 0.00 up_idle + 0.04 5.34 0.00 nx_start + 0.02 5.34 0.00 fdtdump_main + 0.02 5.34 0.00 nxsem_wait + 0.00 5.34 0.00 1 0.00 5.34 hello_main + 0.00 5.34 0.00 1 0.00 0.00 singal_handler + + ``` + + This output shows the performance profile of the program, + including execution time and call counts for each function. + The flat profile table provides a quick overview of where the program spends most of its time. + In this example, `sdelay` and `delay` functions consume the majority of execution time. + This information can be used to identify performance bottlenecks and optimize critical parts of the code.
