Profiling Scilla : Tips

• To profile and view the profiling data, you need to compile our codebase with debug (line number) info.

  • To do that, you have to edit all the dune files in the src/ directory (recursively) of Scilla and add the line (ocamlopt_flags -g)
  • See src/cpp/dune for where to add the line. (as an example. It has c_flags added similarly) then make clean; make to build from scratch.

• You now have a build with debug info (line number info) in the executables.

  • Now just run valgrind --tool=callgrind -v ./bin/scilla-runner .... This will create profile outputs as described here http://kcachegrind.sourceforge.net/html/Usage.html. You can visualize that profiling data with kcachegrind.
  • In short, what valgrind --tool=callgrind does is to run the executable and sample frequently which parts/lines of the (Scilla) code is executing. At the end of it has a "database" of which lines where executed "how many times". That's pretty much what we want: where was most of our time spent.