gcc -O3 testperf.c -o testperf

sb@sb:~$ gcc --version
gcc (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1

sb@sb:~$ perf stat -r 10 ./testperf t

 Performance counter stats for './testperf t' (10 runs):

        932,270792 task-clock (msec)         #    1,000 CPUs utilized            ( +-  0,17% )
                79 context-switches          #    0,085 K/sec                    ( +-  0,41% )
                 0 cpu-migrations            #    0,000 K/sec                    ( +- 66,67% )
               123 page-faults               #    0,132 K/sec                    ( +-  0,08% )
     2.503.934.829 cycles                    #    2,686 GHz                      ( +-  0,18% )
     1.702.393.194 stalled-cycles-frontend   #   67,99% frontend cycles idle     ( +-  0,27% )
   <not supported> stalled-cycles-backend
     2.401.558.621 instructions              #    0,96  insns per cycle
                                             #    0,71  stalled cycles per insn  ( +-  0,00% )
       400.288.990 branches                  #  429,370 M/sec                    ( +-  0,00% )
             8.275 branch-misses             #    0,00% of all branches          ( +-  2,67% )

       0,932290271 seconds time elapsed                                          ( +-  0,17% )

sb@sb:~$ perf stat -r 10 ./testperf c

 Performance counter stats for './testperf c' (10 runs):

       1023,259610 task-clock (msec)         #    1,000 CPUs utilized            ( +-  2,58% )
                86 context-switches          #    0,084 K/sec                    ( +-  2,36% )
                 0 cpu-migrations            #    0,000 K/sec                    ( +- 44,72% )
               123 page-faults               #    0,120 K/sec
     2.812.550.318 cycles                    #    2,749 GHz                      ( +-  0,04% )
       817.018.494 stalled-cycles-frontend   #   29,05% frontend cycles idle     ( +-  0,28% )
   <not supported> stalled-cycles-backend
     3.201.789.125 instructions              #    1,14  insns per cycle
                                             #    0,26  stalled cycles per insn  ( +-  0,00% )
     1.200.349.135 branches                  # 1173,064 M/sec                    ( +-  0,00% )
             9.322 branch-misses             #    0,00% of all branches          ( +-  4,57% )

       1,023239569 seconds time elapsed                                          ( +-  2,58% )

sb@sb:~$ time ./testperf c

real	0m1.050s
user	0m1.051s
sys	0m0.000s
sb@sb:~$ time ./testperf t

real	0m0.939s
user	0m0.939s
sys	0m0.000s