6

I know that I can get the total percentage of branch mispredictions during the execution of a program with perf stat. But how can I get the statistics for a specific branch (if or switch statement in C code)?

nwellnhof
  • 32,319
  • 7
  • 89
  • 113

1 Answers1

9

You can sample on the branch-misses event:

sudo perf record -e branch-misses <yourapp>

and then report it (and even selecting the function you're interested in):

sudo perf report -n --symbols=<yourfunction>

There you can access the annotated code and get some statistics for a given branch. Or directly annotate it with the perf command with --symbol option.

amigadev
  • 396
  • 1
  • 5
  • 5
    It can be more useful to record both `branches` and `branch-misses` events: `sudo perf record -e branches,branch-misses`. With `--symbol` there will be total counts for the function; in annotated code there will be percents of total counts for current function. – osgx Jan 09 '16 at 03:09