Linux load averages are "system load averages" that show the running thread (task) demand on the system as an average number of running plus waiting threads. This measures demand, which can be greater than what the system is currently processing. Most tools show three averages, for 1, 5, and 15 minutes.
These 3 numbers are not the numbers for the different CPUs. These numbers are mean values of the load number for a given period of time (of the last 1, 5 and 15 minutes).
Load average is usually described as "average length of run queue". So few CPU-consuming processes or threads can raise load average above 1. There is no problem if load average is less than total number of CPU cores. But if it gets higher than number of CPUs, this means some threads/processes will stay in queue, ready to run, but waiting for free CPU.
It is meant to give you an idea of the state of the system, averaged over several periods of time. Since it is averaged, it takes time for it to go back to 0 after a heavy load was placed on the system.
- if the averages are 0.0, then your system is idle
- if the 1 minute average is higher than the 5 or 15 minute averages, then load is increasing
- if the 1 minute average is lower than the 5 or 15 minute averages, then load is decreasing
- if they are higher than your CPU count, then you might have a performance problem (it depends)