How can CPU usage be accurately read in PHP on a Linux server?

To accurately read CPU usage in PHP on a Linux server, you can use the `sys_getloadavg()` function. This function returns an array containing the 1, 5, and 15-minute load averages of the system. You can then use these values to determine the CPU usage.

$load = sys_getloadavg();
$cpuUsage = $load[0]; // 1-minute load average
echo "CPU Usage: " . $cpuUsage;