The PHP function memory_get_usage is used to obtain the memory consumption of PHP

1. Function prototype
int memory_get_usage ([ bool $real_usage = false ] )

2. Version compatibility
PHP 4 > = 4.3.2, PHP 5

3. Basic usage and examples
1. Get the current memory consumption

 
<?php 
echo memory_get_usage(); 
$var = str_repeat("liuhui", 10000); 
echo memory_get_usage(); 
unset($var); 
echo memory_get_usage(); 
?> 

Respectively output: 62328 122504 62416
Note: the output value of memory_get_usage() function is bytes units

2, format the output of memory_get_usage()

 
<?php 
function convert($size){ 
$unit=array('b','kb','mb','gb','tb','pb'); 
return @round($size/pow(1024,($i=floor(log($size,1024)))),2).' '.$unit[$i]; 
} 
echo convert(memory_get_usage(true)); 
?> 

Output: 256 kb

3, the custom function to get the array or variable value size

 
<?php 
function array_size($arr) { 
ob_start(); 
print_r($arr); 
$mem = ob_get_contents(); 
ob_end_clean(); 
$mem = preg_replace("/\n +/", "", $mem); 
$mem = strlen($mem); 
return $mem; 
} 
$memEstimate = array_size($GLOBALS); 
?> 

Resources: http: / / cn php. net manual/en/function memory - get - usage. php