For the 5- and 15-minute load averages, the same 63%/37% ratio is computed over 5 minutes and 15 minutes respectively. Hence, the 1-minute load average consists of 63% (more precisely: 1 - 1/ e) of the load from the last minute and 37% (1/ e) of the average load since start up, excluding the last minute. They all decay exponentially, but they decay at different speeds: they decay exponentially by e after 1, 5, and 15 minutes respectively. Mathematically speaking, all three values always average all the system load since the system started up. The three values of load average refer to the past one, five, and fifteen minutes of system operation. Systems calculate the load average as the exponentially damped/weighted moving average of the load number.

Such circumstances can result in an elevated load average which does not reflect an actual increase in CPU use (but still gives an idea of how long users have to wait). This, for example, includes processes blocking due to an NFS server failure or too slow media (e.g., USB 1.x storage devices).

However, Linux also includes processes in uninterruptible sleep states (usually waiting for disk activity), which can lead to markedly different results if many processes remain blocked in I/O due to a busy or stalled I/O system. Most UNIX systems count only processes in the running (on CPU) or runnable (waiting for CPU) states.

Each process that terminates decrements it by 1. Each process using or waiting for CPU (the ready queue or run queue) increments the load number by 1. In Linux, they can also be accessed by reading the /proc/loadavg file.Īn idle computer has a load number of 0 (the idle process is not counted). The w and top commands show the same three load average numbers, as do a range of graphical user interface utilities.

Linux cpu load