What does CPU Usage mean? Mine is often > 100%

[Fish in a Barrel]

This is not a serious issue, but I've noticed that CPU usage is often over 100%. Is this a bug, or is the definition of CPU usage not that straight forward?

See the attached image, which show CPU usage peaking around at 150% during a large file transfer.

This is version 11.1-U1.

 

[Jello]

It is 100% X the number of cores your cpu has. So a 4 core cpu would be maxed out at 400%

 

[MrToddsFriends]

This is not a serious issue, but I've noticed that CPU usage is often over 100%. Is this a bug, or is the definition of CPU usage not that straight forward?

What's the state of the checkbox
System -> Advanced -> Report CPU usage in percentage
in your system?

Mine is not checked (according to the docs this means that CPU usage is based on "jiffies" instead) and on my 8-core Avoton the CPU Usage reporting graph maxes out at 100%. This is on FreeNAS 11.1-U1.

 

[Fish in a Barrel]

That does make sense.

Thanks!

 

[Jello]

If you go into Services and run Netdata and go into the GUI, you can see all kinds of info regarding CPU time. On my machine with 8 cores it shows upto 800%.

 

[toadman]

Now I'm confused. So what the heck does the System > Advanced > Report CPU usage in percentage: Box do? The docs say, "when checked, CPU usage is reported as percentages in Reporting."

So if checked it shows aggregate up to 100%. And if not checked it's 100% x (# cpu cores in the system)?