erlang timer

ticktock.erl

-module(ticktock).

-export([tick/1, tock/1, report/1]).

tick(T) ->
    erlang:put({tick, T}, os:timestamp()).

tock(T) ->
    erlang:put({total, T}, timer:now_diff(os:timestamp(), erlang:get({tick, T}))
                           + case erlang:get({total, T}) of
                                undefined -> 0;
                                Sum -> Sum
                             end).

total(T) ->
    case erlang:get({total, T}) of 
        undefined -> 0;
             Time -> Time
    end.

report(Ts) ->
    Sorted = lists:reverse(lists:keysort(2, [{T, total(T)} || T <- Ts])),
    [{_, Max} | _] = Sorted,
    WithPercentage = [{Elapsed/Max * 100, T, Elapsed} || {T, Elapsed} <- Sorted],
    io:format("~62p", [WithPercentage]).