Can htop Monitor Multiple CPU Cores Individually?

The htop Linux command-line tool is fully capable of monitoring multiple CPU cores individually, providing a real-time, color-coded visual breakdown of how system resources are distributed across each core. Unlike the traditional top command, which aggregates CPU data by default, htop displays each CPU core as a separate, dynamic bar graph at the very top of its interface. This article explains how htop visualizes individual core performance, how to interpret the color-coded resource bars, and how to customize the display to manage high-core-count systems efficiently.

Visualizing Individual CPU Cores in htop

When you launch htop in a terminal, the upper-left section of the interface immediately displays your CPU utilization. Each individual CPU core or hardware thread (in the case of Hyper-Threading) is assigned its own numbered row, starting from 1 or 0 depending on your configuration.

Next to each numbered core is a progress bar made of text characters (|||||||), followed by a percentage showing the current load on that specific core. If a system has 4 cores with hyper-threading, htop will cleanly display 8 separate bars, allowing sysadmins to instantly spot if a single-threaded process is pinning a specific core to 100% while others sit idle.

Understanding the Color-Coded CPU Bars

The individual core bars use a specific color-coding system to give you a granular look at what is consuming your CPU cycles on that specific core:

• Blue: Low-priority processes (tasks that have been “niced”).
• Green: Normal user-space processes (the applications and services you run).
• Red: Kernel-space/system processes (time spent handling OS drivers and system calls).
• Cyan/Aqua: Virtual machines or guest operating systems (if applicable).

Managing High-Core-Count Systems

On enterprise servers or high-end workstations with 64, 128, or more CPU cores, displaying every core as a single vertical list can consume the entire terminal screen, leaving no room to see the running processes below. To solve this, htop allows you to customize the layout:

• Multi-Column Setup: By entering the setup menu (pressing F2 or S), you can move the CPU meters into two or four parallel columns, drastically reducing the vertical space they occupy.
• LED or Text Modes: You can change the display style of the CPU monitors from a bar graph to a simple text percentage or an LED-style digital readout.
• Aggregated View: If individual core tracking is no longer necessary, you can replace the split view with a single, unified “CPU average” bar to save screen space.