Linux CPU Load

Linux and other *nix-like Operating Systems display CPU Load in a way that may not be easily interpreted. The CPU usage/load percentage is reported in percentage per-core, so on an 8 core system, it is possible to see a CPU Load of 800%.

This is also related to how Load Averages are reported. A load of 1 per CPU core is the maximum that should be considered “acceptable”. It’s much like an expressway. If you have a single CPU core, or expressway lane, a Load Average of 1 means there’s a steady line of cars in that single lane, all flowing along at posted speeds, and the last car in the lane would get to it’s destination exactly when it would expect to. A Load Average of 2 on a single-core/lane would mean that there’s a backup of cars waiting to merge into the single lane of traffic, and that traffic is moving at less than posted speeds.

This can be expanded out to multiple cores/lanes as well. For instance, a 8 core CPU, or 4 lane highway would have an acceptable Load Average of 8. This would signify all 8 cores/lanes having a steady line of traffic moving along at posted speeds, while a load higher than that would be like traffic merging in, cars changing lanes, and everything moving slower than it should, and the last car in the line having to wait longer to get to it’s destination, or the last task sent to the CPU queue would have to wait longer for CPU time.


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