Performance of constants. PHP 7.1.10 32 bits (Opcache active, windows 10 i7-64bits) but apparently the trends is the same with the 5.x
using a constant declared by DEFINE('CNS',value) : 0.63575601577759s
using a constant declared by const CNS=value : 0.61372208595276s
using a variable declared by $v=value : 0.51184010505676s
In average, the use of DEFINE and CONST is around the same with some sightly better performance of CONST instead of DEFINE. However, using a variable is around 10-50% better than to use a constant. So, for a performance intensive task, constant is not the best option.
$p1=microtime(true);
$x=0;
for($i=0;$i<50000000;$i++) {
$x+=CNS;
}
$p2=microtime(true);
