测试使用static变量和自身变量时实例化变量后的内存消耗，实验证明，Static会消耗很少的内存，前提是实例化的类中数据足够多，以至于类本身需要的内存可以忽略

Perform_dynamic_static_memory_use.php

*/
/**
 * test memory comsuming
 */

class base1{
    public $a;
    public $b;
    public $c;
    public $d;
}
class base2{
    public static $a;
    public static $b;
    public static $c;
    public static $d;
}

class sonfrombase1 extends base1{
    public function __construct($b) {
        $this->a=$b;
        $this->b=$b;
        $this->c=$b;
        $this->d=$b;
    }
   
}

class sonfrombase2 extends base2{
    public function __construct($b) {
        parent::$a=$b;
        parent::$b=$b;
        parent::$c=$b;
        parent::$d=$b;
    }
   
}
echo "usenow: ";
echo memory_get_usage();
echo "<br>";

$usest=  memory_get_usage();
$son1s=array();
for($i=0;$i<10000;$i++){
    $son1s[$i]=new sonfrombase1(array(1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9));
}
usleep(5000000);
$useend=  memory_get_usage();
$son1use=$useend-$usest;
foreach ($son1s as $value) {
    unset($value);
}
echo "use then: ";
echo memory_get_usage();
echo "<br>";

$usest=  memory_get_usage();
$son2s=array();
for($i=0;$i<10000;$i++){
    $son2s[$i]=new sonfrombase2(array(1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9));
}
usleep(5000000);
$useend=  memory_get_usage();
$son2use=$useend-$usest;
foreach ($son2s as $value) {
    unset($value);
}
echo "use last: ";
echo memory_get_usage();
echo "<br>";

echo 'local use: ';
echo $son1use;
echo "<br>";

echo 'static use: ';
echo $son2use;
echo "<br>";

echo "local Use more than static Use up to:";
echo ($son1use-$son2use)/$son2use;