top (pictured below... above is btop) is the first utility everyone recommends to monitor Linux (or any form of UNIX, including macOS) resource usage. It's efficient, available almost everywhere... but it's also a bit basic. It shows essential metrics, but looks like it's from the 80s. There are ways to brighten it up, like highlighting active processes or changing color schemes, but it's not the only game in town!
Nowadays, there are a lot of modern monitoring tools—and some not so modern, but immensely useful—to choose from. This blog post will run through some of the ones I rely on most often. Let me know in the comments if you use any others I didn't cover!
Contents
If you'd like to see all these tools in action, check out the video that goes along with this blog post, embedded below:
s-tui
# Install on Debian/Ubuntu Linux
apt install -y stress-ng s-tui
If I want to quickly observe the system's CPU frequency and temperatures while running a stress benchmark, this is by far the best way.
I originally discovered this tool through ServeTheHome—Patrick uses it and displays it on the giant screen behind him to monitor core to core stability when running a system under load.
It has two basic modes, 'Monitor' and 'Stress', and while running in Stress mode, it will use stress or stress-ng to stress all CPU cores (you can configure stress options within s-tui's configuration).
I've used it on Linux and macOS, and it seems to pick up the right temperature sensors on most hardware, even exotic systems like the AmpereOne!
htop
sudo apt install htop
htop is often installed by default (e.g. on Raspberry Pi OS), and is like top, but focuses visually on CPU metrics more than memory. It provides more visual indication of system load through bar graphs, and it's usually a tossup whether I choose htop or top.
atop
sudo apt install atop
atop breaks out a lot of critical performance metrics into a dizzying array of metrics, with a process list below. There are two features I like about atop that draws me to it instead of other tools when I'm debugging hardware bottlenecks:
First, it uses color sparingly to indicate resources reaching saturation (e.g. 90% of disk, memory, or CPU usage turns that metric red).
Second, it breaks out IRQ consumption, network packets in and out, and some other metrics that are either hidden or buried in other tools. This tool has been especially helpful when troubleshooting bottlenecks like network file copy slowdowns, which sometimes are affected by CPU core affinity, PCIe bottlenecks, or disk IO (or a combination of all!).
iftop
sudo apt install iftop
If I'm just focused on bandwidth monitoring—seeing how much data is going through a network interface, there's no simpler tool than iftop. It shows total bandwidth over the interface, along with a running total of download and upload size. Then it lists every connection with traffic up and down, with a simple bar graph display for each.
iotop
sudo apt install iotop
What iftop is for network bandwidth, iotop is for disk bandwidth.
The nice party trick is it also breaks out the disk IO by process, so if you are experiencing slow disk access, or want to see what processes are hogging a drive, this is the quickest way to get at that info.
If you want to get even fancier, sysdig (sudo apt install -y sysdig) comes with a console UI csysdig which lets you dig directly into processes by volume of data written or ops! Very handy.
nvtop
sudo apt install nvtop
nvtop is a lightweight task viewer for AMD, Intel, Nvidia, and Apple GPUs. Some tools like btop (shown later) include very simple GPU metrics (sometimes...), but nvtop gives you all the hardware details, like power consumption, fan speed, memory consumption, and a process breakdown.
There are tools like radeontop and amdgpu_top for AMD, or nvitop for Nvidia... but nvtop is almost universally available, and works on the largest variety of GPUs. It's nice to know one tool for all, and even nicer when it's an apt install away. Or brew install nvtop on macOS!
asitop
pip3 install asitop
I try not to get too platform-specific with my tooling, but sometimes when I'm on a Mac, I don't have access to the full gauntlet of process monitoring tools I get on Linux.
Lucky for me, there's asitop, which is a handy visual tool to monitor CPU, GPU, power, and clock speeds. It even breaks down visuals based on E and P cores!
btop
sudo apt install btop
Now we get to it—the Lamborghini of tops. Not only does it have full color, mouse support, and a sensible video-game-like menu system (no arcane hidden features here!), it makes you look like you're hacking away on TV set.
The visuals aren't all eye-candy, either. Color schemes and almost infinite settings and layouts mean you can set it up for precisely the metrics you want to monitor, usually with just a few keystrokes.
It's worth spending the time to learn some of btop's options. btop is usually the first tool I install when getting a feel for a new computer or SBC. Sometimes the colors can get a bit wacky, especially over SSH sessions, but a quick trip to the menus (o) and setting Truecolor to False fixes that right up.
This is by far the tool I get the most comments about when it appears in one of my YouTube videos. The visuals are not only pretty, but functional.
perf
sudo apt install linux-perf
And after the beauty of btop, we have to go in the complete opposite direction. perf isn't a top at all! Well, then, why is it in the list?
Because usually once you monitor a system with a lightweight tool like btop or atop, you need to actually figure out the bottleneck. And perf has deep kernel integration to pull out performance data you didn't even know existed!
I can't even scratch the surface of what it can do—I'll let the guy who I've learned the like 0.2% of perf's features from describe it so much better: Brendan Gregg's perf Examples. He even writes a book on Linux performance monitoring!
And yes, that's the same Brendan Gregg famous for Shouting in the Datacenter.
wavemon
sudo apt install wavemon
Since we're off on a tangent of non-top monitoring tools, I figured I'd throw an honorable mention out to wavemon.
Before I discovered this tool, I would use watch -n 1 with nmcli or iwconfig... but that was not ideal, and a tool like iwconfig occupies some weird head space where I can never remember the exact name, because there's also ipconfig or ifconfig or ip or whatever other networking tools that have overloaded those registers in my brain.
But now I can see precisely which direction to orient my external wifi antenna, or find a way to eke out an extra 100 Mbps from an otherwise-stable connection!
That rounds out my list of the top 10 ways to monitor Linux... but as I mentioned in the perf section, this is barely scratching the surface. Seriously, go read through Brendan Gregg's Linux Performance page if you want to go much, much deeper.