Teste de benchmark de um exemplo de código branchless para verificar qual número é menor

benchmark_smaller_branchless.c

#include <stdio.h>
#include <stdlib.h>
#include "metric.h"  // https://github.com/Silva97/metric

int smaller(int a, int b)
{
  if (a < b) {
    return a;
  }

  return b;
}

int smaller_branchless(int a, int b)
{
  return a * (a < b) + b * (b <= a);
}

int main(void)
{
  volatile int x = 5, y = 9;
  METRIC_CALL(10000, smaller, x, y);
  METRIC_CALL(10000, smaller_branchless, x, y);
  return 0;
}

/*
┌─[~]
└─[felipe]─$ gcc tst.c -o tst
┌─[~]
└─[felipe]─$ ./tst
<BENCH> tst.c: smaller(x, y) x 10000
        88 clocks, 0.00008700 secs
<BENCH> tst.c: smaller_branchless(x, y) x 10000
        104 clocks, 0.00010300 secs
┌─[~]
└─[felipe]─$ ./tst
<BENCH> tst.c: smaller(x, y) x 10000
        88 clocks, 0.00008600 secs
<BENCH> tst.c: smaller_branchless(x, y) x 10000
        100 clocks, 0.00009800 secs
┌─[~]
└─[felipe]─$ ./tst
<BENCH> tst.c: smaller(x, y) x 10000
        88 clocks, 0.00008700 secs
<BENCH> tst.c: smaller_branchless(x, y) x 10000
        134 clocks, 0.00013200 secs
┌─[~]
└─[felipe]─$ ./tst
<BENCH> tst.c: smaller(x, y) x 10000
        89 clocks, 0.00008700 secs
<BENCH> tst.c: smaller_branchless(x, y) x 10000
        106 clocks, 0.00010400 secs
┌─[~]
└─[felipe]─$ 
*/