How to compress or hide the processors at top of htop on large machines

htopmulti-core

I like to use htop to show me how the server is being used.

Unfortunately with modern servers, the machine might have 48 or even 120 cores. This means that
I can only see the first few lines of htop and never the second half of the htop display that
shows which processes are using the machine.

How can I hide all of the core-usage lines or even better aggregate them for some sort of statistic?

Best Answer

Open the setup screen using F2 or ShiftS. The first page of that screen is dedicated to configuring header meters, so you can remove "CPUs" and add "CPU average".

In recent htop versions, there also are "CPUs (1&2/4)" and "CPUs (3&4/4)" meters showing two cores per line, though this is more of use on 8–32 core systems.

To save two more lines, open the "Display options" page and turn off "Leave a margin around header".

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Regarding "Load" and CPU%, wikipedia has detail explanation and example, following is a partial quote

An idle computer has a load number of 0 and each process using or waiting for CPU (the ready queue or run queue) increments the load number by 1. Most UNIX systems count only processes in the running (on CPU) or runnable (waiting for CPU) states. However, Linux also includes processes in uninterruptible sleep states (usually waiting for disk activity), which can lead to markedly different results if many processes remain blocked in I/O due to a busy or stalled I/O system. This, for example, includes processes blocking due to an NFS server failure or to slow media (e.g., USB 1.x storage devices). Such circumstances can result in an elevated load average, which does not reflect an actual increase in CPU use (but still gives an idea on how long users have to wait).

Systems calculate the load average as the exponentially damped/weighted moving average of the load number. The three values of load average refer to the past one, five, and fifteen minutes of system operation.

For single-CPU systems that are CPU bound, one can think of load average as a percentage of system utilization during the respective time period. For systems with multiple CPUs, one must divide the number by the number of processors in order to get a comparable percentage.

The bars maybe busy moving, but they never reach 100%, which will indicate the cpu/core is fully utilized. The bar is only a visualization of the cpu utilization %, which are at 27%, 26.5%, 24.5%, 24.7% and 71.7%. All cpu cores still have power to "spare". They are all under utilized at that point.

A fully utilized 5 core/cpu system will have load 5 or above.
Regarding the Java rows, they are parent(PID=5073) and child processes. I cannot explain why the parent accumulate the most cpu time. That really depends on the internal logic of the program. However, according the TIME+, those child processes did consume cpu time, with the last one (PID=5074) accumulated the most.

htop Colors – What Do the Colors Mean in htop?

Press h inside htop for quick help.

CPU

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

Memory

Green         : Used memory
Blue          : Buffers
Yellow/Orange : Cache

Best Answer

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