For Nvidia GPUs there is a tool nvidia-smi that can show memory usage, GPU utilization and temperature of GPU.
For Intel GPU's you can use the intel-gpu-tools.
AMD has two options
fglrx (closed source drivers):
aticonfig --odgc --odgtAnd for mesa (open source drivers), you can use RadeonTop
sudo apt install radeontop radeontop
Source:GPU usage monitoring
Answer from Mitch on askubuntu.comFor Nvidia GPUs there is a tool nvidia-smi that can show memory usage, GPU utilization and temperature of GPU.
For Intel GPU's you can use the intel-gpu-tools.
AMD has two options
fglrx (closed source drivers):
aticonfig --odgc --odgtAnd for mesa (open source drivers), you can use RadeonTop
sudo apt install radeontop radeontop
Source:GPU usage monitoring
You can use gpustat, which is a simple command-line script (wrapper for nvidia-smi) for querying and monitoring GPU status:

One small aspect where Linux is really lacking is GPU resource monitoring
GUI / CLI tool to view GPU usage?
GPU usage monitoring (CUDA) - Unix & Linux Stack Exchange
Do linux have system monitor that can see GPU usage for each program like W10?
For the non-Nvidia among us. Not per application but you can get usage.
intel-gpu-tools package
$ sudo intel_gpu_top
https://i.imgur.com/IvNMjTD.png
radeontop package
$ sudo radeontop
https://i.imgur.com/zKsy61U.png
EDIT: You can however have Intel GPU top run a specific command and monitor that.
$ sudo intel_gpu_top -e <some_game_here>More on reddit.com
Videos
Resource monitoring in general is not really a big deal for us in Tux-land. From great CLI tools, like all of the *tops (top, htop, bpytop, gotop, etc.) to great GUI tools (with KDE's newer resource monitor particularly REALLY great when it comes to presenting resource usage in a clean way to the user). But those really miss one essential aspect of resource monitoring, specially for desktop users. GPU usage.
Want to check how hard your $1000 graphics card is being stressed by that shiny new AAA game on Windows or in some sick benchmark or workflow? Just open Task Manager and check it, easy as that. Wanna do it on Linux? Well... get ready for a ride. Figure out what CLI tool works best for your GPU brand and go get'em at the terminal, champ! What, you want GUI tools? All you get is some small text in NVIDIA Settings for those that use NVIDIA.
It can get worse depending on what specific aspect of the GPU is being used. Want to check if your computer is properly using hardware encoding/decoding? Well, you're in luck (with CLI tools), nvidia-smi dmon and intel_gpu_top are really good. Unless you use AMD that is, since radeontop still doesn't have a way to expose GPU encoding/decoding.
I'm quite aware that developers are scarce and that this is definitely not a priority (and do I wish I knew enough code-fu to be able to do it myself), but it's kind of baffling that an integration with our DE's system resource monitoring tools doesn't exist for that particular aspect of the system. It's one of those many small papercuts you only realize hurts when you really need it.
EDIT: Yeah, I used a bad example for my point. Mangoud (specially with GOverlay) works great for monitoring your system during gaming or benchmarks. I meant more in the regular desktop usage sense of monitoring then in the gaming sense. Video editing or 3D modeling would be a better example of workflows where Mangohud wouldn't be the obvious answer for monitoring the resource usage.
I've done some research on google and did not find much.
Mint's system monitor does not have such feature unlike the Windows task manager, too bad. Are there any GUI / CLI tools that allow me to view GPU usage? I'd prefer GUI but CLI tools are fine too.
I'm using an Intel Iris Xe (80EUs) with i5 12500H
For Nvidia GPUs there is a tool nvidia-smi that can show memory usage, GPU utilization and temperature of GPU. There also is a list of compute processes and few more options but my graphic card (GeForce 9600 GT) is not fully supported.
Sun May 13 20:02:49 2012
+------------------------------------------------------+
| NVIDIA-SMI 3.295.40 Driver Version: 295.40 |
|-------------------------------+----------------------+----------------------+
| Nb. Name | Bus Id Disp. | Volatile ECC SB / DB |
| Fan Temp Power Usage /Cap | Memory Usage | GPU Util. Compute M. |
|===============================+======================+======================|
| 0. GeForce 9600 GT | 0000:01:00.0 N/A | N/A N/A |
| 0% 51 C N/A N/A / N/A | 90% 459MB / 511MB | N/A Default |
|-------------------------------+----------------------+----------------------|
| Compute processes: GPU Memory |
| GPU PID Process name Usage |
|=============================================================================|
| 0. Not Supported |
+-----------------------------------------------------------------------------+
For linux, use nvidia-smi -l 1 will continually give you the gpu usage info, with in refresh interval of 1 second.