Something

// In index.php right after <?php have:

function getExecutionTime($dp = 4, $reset = false)
{
    global $__EXECUTION_TIMER;
    
    if($reset)
    {
        list($usec, $sec)  = explode(" ", microtime());
        $__EXECUTION_TIMER = $usec + $sec;
        return true;
    }
    else
    {
        list($usec, $sec) = explode(" ", microtime());
        return round(($usec + $sec) - $__EXECUTION_TIMER, $dp);
    }
}

getExecutionTime(0, true);





// In the template have:

echo getExecutionTime();