High load average without visible CPU consuming processes. CPU scaling, kondemand

When you see a high load average, however no real CPU consuming processes, but with kondemand in top command, then most probably SPU scaling is the core of issue. Example ‘top’ output:

 

Check what scaling is set to:

If you see ondemand there, it means that scaling is enabled. It actually enables the operating system to scale the CPU frequency up or down in order to save power. CPU frequencies will be scaled automatically depending on the system load, in response to ACPI events, or manually by userspace programs.

To be sure CPU has been scaled you may compare real CPU frequency to hardware:

 

model name : Intel(R) Xeon(R) CPU X7550 @ 2.00GHz
cpu MHz : 1067.000

 

Resolution is simple – switch off scaling, this should be done for all CPU cores, but here is one-liner for it:

This will help on already running server however to resolve it completely you have to remove cpuspeed rpm package.

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