I am trying to find time required to execute some function using php.
I want accuracy of milli or micro seconds but i get difference in seconds.

The code is as follows:

```
<?php

$time_start = microtime(true);

usleep(2000000);

$time_end = microtime(true);

$time = $time_end - $time_start;

echo "Did nothing in $time micro seconds\n";

?>

```

The output i get is 2 micro seconds but it should be 2000000 micro seconds according to program.

If i keep usleep(100) it will give me 0 difference.

Please help me with some solution to this.