Code Profiling

22 Nov 2021 | computer programming

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Optimizing

• https://en.wikibooks.org/wiki/Optimizing_C%2B%2B
• https://www.slideshare.net/EmertxeSlides/embedded-c-optimization-techniques

Perf

Perf is a set of Linux tools for command profiling.

• Type sudo pacman -S perf to install the performance analysis tool for Linux
• Type perf list to list all currently known events
• Type perf stat <command> to get CPU counter statistics for the specified command
• Type perf record <command> to sample on-CPU functions for the specified command
• Type perf report to display perf.data (created by perf record)

Links:

• perf wiki
• perf examples

Flame Graph

Flame graphs are visualizations of profiled software, allowing for the most frequence code paths to be identified quickly and accurately.

1. Type git clone https://github.com/brendangregg/FlameGraph to acquire FlameGraph tools
2. Type perf record -F max -a -g -- ./<executable> to capture executable
3. Type perf script > out.perf to read perf.data (created by perf record) and save trace output
4. Type ./FlameGraph/stackcollapse-perf.pl out.perf > out.folded to fold stack samples into single lines
5. Type ./FlameGraph/flamegraph.pl out.folded > kernel.svg to render a SVG
6. Type brave kernel.svg to view the SVG

Links:

• Flame Graphs
• FlameGraph git