Load average in Linux: loadavg and uptime

Load average is the average number of processes running or waiting for the CPU or disk, over 1, 5 and 15 minutes.

Common cases

uptime                 # three load numbers at the end of the line
cat /proc/loadavg      # the same numbers, as a file
nproc                  # how many CPU cores are available
w                      # load plus who is logged in

How it works: compare load with the core count

The three numbers are the load over the last 1, 5 and 15 minutes, and you read them against the number of cores. On 4 cores a load of 4.0 means the CPU is fully busy but not queued; 8.0 means the load is twice the core count. A falling series (say 8, 4, 2) means a spike is passing; a rising one means trouble is building. On Linux the load also counts processes waiting on disk, so high load can happen with an idle CPU.

Used in

You need this in the lesson Monitoring. The theory is the chapter Monitoring and bottlenecks.

See also

Memory: free, The vmstat command, Viewing processes.

Try it

Open the sandbox: a real throwaway Linux terminal in your browser. Run the commands above by hand - the container is deleted when you leave.