octave:1> a = 1; b = 1; tic; for i=1:1000; for j=1:1000; a = a + b; end; end; toc Elapsed time is 4.21553 seconds. octave:2> jit_enable(1) octave:3> a = 1; b = 1; tic; for i=1:1000; for j=1:1000; a = a + b; end; end; toc Elapsed time is 0.891052 seconds.