Erlang Run-Time System Application (ERTS)

Internal Documentation

Version 12.0.2

Chapters

3 Counting Instructions

Here is an example that shows how to count how many times each instruction is executed:

$ (cd erts/emulator && make icount)
 MAKE	icount
make[1]: Entering directory `/home/uabbgus/otp/erts/emulator'
  .
  .
  .
make[1]: Leaving directory `/home/uabbgus/otp/erts/emulator'
$ cat t.erl
-module(t).
-compile([export_all,nowarn_export_all]).

count() ->
    erts_debug:ic(fun benchmark/0).

benchmark() ->
    %% Run dialyzer.
    Root = code:root_dir(),
    Wc1 = filename:join(Root, "lib/{kernel,stdlib}/ebin/*.beam"),
    Wc2 = filename:join(Root, "erts/preloaded/ebin/*.beam"),
    Files = filelib:wildcard(Wc1) ++ filelib:wildcard(Wc2),
    Opts = [{analysis_type,plt_build},{files,Files},{get_warnings,true}],
    dialyzer:run(Opts).
$ $ERL_TOP/bin/cerl -icount
Erlang/OTP 22 [RELEASE CANDIDATE 1] [erts-10.2.4] [source-ac0d451] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe] [instruction-counting]

Eshell V10.2.4  (abort with ^G)
1> c(t).
{ok,t}
2> t:count().
           0 badarg_j
           0 badmatch_x
           0 bs_add_jsstx
           0 bs_context_to_binary_x
            .
            .
            .
   536461394 move_call_last_yfQ
   552405176 allocate_tt
   619920327 i_is_eq_exact_immed_frc
   636419163 is_nonempty_list_allocate_frtt
   641859278 i_get_tuple_element_xPx
   678196718 move_return_c
   786289914 is_tagged_tuple_frAa
   865826424 i_call_f
Total: 20728870321
[]
3>