Measure mobiles computational performance

Question

The source code here measures mobile phones computational performance. Is there anybody who can explain for me what is the thougt behind the pi? What does pi?
computationPerformance= pi(10);
1617 //allows the JIT compiler to optimize the function pi(long)
1618 computationPerformance= 400000 / pi(500000);
1823 private int pi(long max)
1824 {
1825 int p= 0;
1826 long m= 100000000l;
1827 long start= System.currentTimeMillis();
1828 while (max > 0)
1829 {
1830 p += (int) (m / (max * max--));
1831 }
1832 long duration= System.currentTimeMillis() - start;
1833 if (p - 4 == 0)
1834 {
1835 // Stupid test (never true) to fool the optimizer, which would think p is useful.
1836 duration= 0;
1837 } /* we could compute PI this way :
1838 double pi;
1839 pi=Math.sqrt(6.0d*p/(double)m);
1840 */
1841 return (int)duration;
1842 }

Answer 1

Well, it id often used in benchmarks... but there is no relationship. Any other algorithm would do just as well.