ErlangAndKCachegrind.md

How to use KCachegrind / QCachegrind to visualize Erlang traces

install qcachegrind

brew install qcachegrind

install erlgrind

Trace some Erlang

Fun = fun() ->
  random:seed(erlang:now()),
  list:usort([random:uniform(100) || _ <- lists:seq(1, 1000)])
end,

fprof:trace([start, {file, "/tmp/erl_trace"}, verbose, {procs, self()}]).
Fun()

fprof:trace([stop]).
fprof:profile({file, "/tmp/erl_trace"}).
fprof:analyse({dest, "/tmp/outfile.fprof"}).

Convert trace

~/src/erlgrind/src/erlgrind /tmp/outfile.fprof /tmp/callgrind.out

open with qcachegrind

qcachegrind /tmp/callgrind.out

Explore

using fprofx

fprofx basically does the same but removes the call to suspended and lists GC.