Usando o statistics do Prolog – cputime

?- statistics( cputime , X1), format(‘\t ~f’,[X1]), statistics( cputime , X2), format(‘\t ~f’,[X2]), Z is X2 -X1, write(Z).
0,860000 0,8600000.0
X1 = 0.86,
X2 = 0.86,
Z = 0.0.

Para outras opções consulte:

?- help(statistics/2).