What is the best way to get the most useful output from oprofile?

Question

Using tools such as:

• opreport
• opcontrol
• opannotate

I am starting to use this tool and trying to find the best combinations, examples to get the most out of profiling.

Thanks

Answer 1

Look at the KCachegrind - it's a profile data visualization tool.

KCachegrind visualize data files generated by Callgrind profiler tool. But with conversion scripts, KCachegrind is able to visualize output of other profilers like OProfile.

Answer 2

gprof2dot is the most amazing visualization tool for profile data.

opcontrol --shutdown
opcontrol --callgraph=7
opcontrol --image=<abs/path/to/your/execuable>
opcontrol --start

... time passes ...

opcontrol --dump
opreport -c > profile_info.txt
gprof2dot.py -f oprofile --strip profile_info.txt | dot -Tsvg > profile_graph.svg
inkscape profile_graph.svg

gprof2dot's --skew option is really nice when drilling down the actual problem code.

Remeber you can't set callgraph if you've manually set the event counter to a low number. Be default the when using the --callgraph option the minimum counter is 15 times larger than the one listed in --list-events