htop screenshot

For the CPU cores, I think that blue means nice, green normal CPU use and red I/O. But I'm not sure and I haven't found a definite answer.

Then there are the colors for memory. What do green, blue and yellow mean there?

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    I lack the reputation credits to flag this as duplicate, but see the answer at serverfault.com/questions/180711/…, which is a copy of your question and has been answered. – Caleb Xu Jan 8 '14 at 4:04
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    @CalebXu You cannot flag it as a duplicate of a question on another site, but you can post an actual answer here, linking to it. – slhck Jan 8 '14 at 8:08

Press h inside htop for quick help.


Blue      : Low-priority threads
Green     : Normal priority threads
Red       : Kernel threads
Turquoise : Virtualization threads


Green         : Used memory
Blue          : Buffers
Yellow/Orange : Cache
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  • Why is the kernel CPU on the right? Wouldn't it make sense to put it on the left? – Aaron Franke Feb 5 '18 at 19:45
  • @AaronFranke, because your processes are expected to primarily use User CPU. Kernel CPU is when your process calls a kernel function which should use a lot less time in %. – Alexis Wilke Oct 28 '19 at 0:40

Also, in the list of processes, there are some that appear in Green. The black ones are main processes and the Green ones are threads. In my example below, I'm running a repair on a Cassandra node and as we can see most entries are threads.

enter image description here

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    thank you brother you read my mind – Austin Adams Jun 13 '20 at 19:37

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