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Created January 23, 2017 12:06
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Perf usage
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perf-usage.org

Profile the program

perf record -g ./my-program

where g instructs perf to create a call graph.

Known issue

To produce meaningful call-graphs, perf needs a way to read the call stack. To achieve this it relies on frame-pointers, thus we need to instruct the compiler to not omit them. To do so we need to compile with --fno-omit-frame-pointer.

Read the results

~perf report -g ‘graph,0.5,caller’~

where:

  • the graph part instructs perf to keep the percentages normalized to the total execution time, i.e., avoid reporting percentages as the portion of time relative to the parent function,
  • the 0.5 part filters out functions taking less than 0.5% of the execution time,
  • the caller part instructs perf to produce the call graph from the caller to the callees, instead of the default from callee to callers (backtrace like).
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