xload

xload [options]

-display display
    Specifies the X server to connect to.

-geometry geometry
    Specifies the initial size and location of the xload window.

-update seconds
    Sets the interval in seconds between updates of the load average graph. The default is 5 seconds.

-scale integer
    Sets the vertical scale of the graph in pixels per load average point. For example, a value of 1 would mean 1 pixel per load average point. The default is typically 8.

-label string
    Specifies a string to display as a label above the load average graph. Useful for identifying specific machines or monitoring instances.

-nolabel
    Disables the display of the label string above the graph.

-hl color
    Sets the color of the highlight line, which represents the current load average. Defaults to the foreground color.

-jumpscroll pixels
    Specifies how many pixels the graph should scroll horizontally when updated. A value of 0 means the graph redraws from the right; a positive value scrolls existing data.

-rv / +rv
    -rv (reverse video) swaps the foreground and background colors. +rv restores normal video (default).

-bg color
    Sets the background color of the xload window.

-fg color
    Sets the foreground color, used for text, borders, and the graph itself unless overridden by -hl.

-bd color
    Sets the color of the window border.

-bw pixels
    Sets the width of the window border in pixels.

-fn font
    Specifies the font to be used for displaying the label string.

The xload command is a venerable utility for the X Window System, providing a real-time, graphical representation of the system's load average. It continuously samples and plots the load average, which indicates the number of processes that are either running or waiting to run on the system. This visual feedback helps users quickly assess the system's activity level. While simple compared to modern monitoring tools, xload is invaluable for quickly glancing at system performance without needing to switch to a terminal or launch more complex applications. Its appearance and behavior can be extensively customized through command-line options or X resources, allowing users to define colors, update intervals, scaling, and window geometry to suit their preferences and integrate seamlessly into their desktop environment.

xload is specifically designed for the X Window System; it cannot be run in a text-only terminal environment. While useful for quick visual checks, it offers limited detail compared to dedicated system monitoring tools like top or htop. The load average value itself can be misleading if the number of CPU cores is not considered; a load of '2.0' on a single-core system is very high, but on an 8-core system, it indicates minimal load per core.

Like many X applications, xload supports extensive customization via X resources. Options can be set in the X resource database (e.g., in `~/.Xresources` or `~/.Xdefaults`) using the syntax `XLoad*: `. For example, to set the update interval, you could use `XLoad*update: 2`. This provides a persistent way to configure xload's appearance and behavior across sessions without needing to specify command-line options every time.

The load average displayed by xload represents the average number of processes in the run queue (running or waiting for CPU) over specific periods (typically 1, 5, and 15 minutes, though xload usually displays a smoothed version of the 1-minute average). A load average of 1.0 on a single-core system indicates the CPU is fully utilized. On a multi-core system, a load average approximately equal to the number of CPU cores indicates full utilization without processes waiting excessively. For example, a load of 4.0 on a quad-core system means all cores are busy. Values significantly higher than the number of cores suggest a bottleneck where processes are queuing up.

xload is one of the earliest graphical utilities developed for the X Window System, originating from the MIT X Consortium. It has been a standard component of X Window System distributions since its inception, providing a simple yet effective way to monitor system load visually. Due to its focused and stable functionality, xload has undergone relatively few fundamental changes over its long history, remaining a reliable, low-resource tool for basic performance monitoring in X environments.

uptime(1), top(1), htop(1), vmstat(8), sar(1)