How to Check Which GPU Is Being Used on Linux with 1 Command

In Linux computing, understanding which Graphics Processing Unit (GPU) is currently active is crucial for optimizing performance and resource allocation. Whether you’re a gamer seeking the best graphics experience, a graphic designer in need of precise rendering capabilities, or a researcher conducting computational analyses, knowing how to check which GPU is being used can significantly impact your workflow.

This article introduces the essential methods and tools designed to identify the active GPU on a Linux system, providing a foundation for users to leverage their hardware’s full potential.

Identifying Active GPUs in Linux

Understanding GPU Management in Linux

Linux systems are known for their robust handling of hardware resources, including the management of multiple GPUs. In such environments, GPUs can be categorized as active or inactive, depending on whether they are currently being used to render graphics or perform computations. Linux’s flexible architecture allows users to switch between GPUs based on their current needs, optimizing performance and power consumption. This capability is especially beneficial in systems equipped with both integrated graphics and discrete GPUs, enabling users to select the most appropriate hardware for their tasks.

Using Command-Line Tools

lspci Command

The lspci command is a versatile tool for listing all PCI devices on a system, including GPUs. To identify the active GPU, users can execute the command:

lspci | grep VGA

This command filters the list of PCI devices to show only those classified as VGA controllers, which are typically GPUs. By examining the output, users can determine which GPUs are present in the system. However, identifying the active GPU may require further investigation into the specific configurations and drivers in use.

glxinfo Command

The glxinfo command, part of the mesa-utils package, provides detailed information about the OpenGL configuration, including which GPU is currently rendering graphics. To use glxinfo, ensure that mesa-utils is installed:

sudo apt-get install mesa-utils

Then, run:

glxinfo | grep "OpenGL renderer"

This command reveals the GPU that is actively rendering OpenGL graphics, offering a straightforward method to check which GPU is being used for graphical output.

nvidia-smi Command

For systems equipped with NVIDIA GPUs, the nvidia-smi tool is an invaluable resource for monitoring GPU activity. It displays a list of all NVIDIA GPUs in the system and provides real-time data on their usage, temperature, and more. To check GPU activity, simply run:

nvidia-smi

This command outputs a comprehensive overview of NVIDIA GPU statuses, helping users identify which GPUs are active and how they are being utilized.

Table 1: Comparison of Command-Line Tools for GPU Monitoring

Graphical Methods for Monitoring GPU Usage

NVIDIA Settings GUI

Users with NVIDIA GPUs have the advantage of accessing the NVIDIA Settings GUI, a comprehensive tool designed for monitoring and managing GPU settings. This graphical interface allows users to:

• View real-time GPU activity
• Adjust performance settings
• Monitor temperature and power usage

To access the NVIDIA Settings GUI, open your terminal and type:

nvidia-settings

This command launches the GUI, providing a user-friendly way to monitor GPU activity and manage various settings. It’s particularly useful for quickly checking which GPU is being used without diving into command-line tools.

Third-Party Tools

Several third-party applications offer graphical interfaces for monitoring GPU usage across different GPU brands, including AMD and Intel, alongside NVIDIA. Some notable examples include:

• GpuTest: A cross-platform utility that provides GPU stress tests and comparisons.
• GOverlay: An interface for managing Linux gaming overlays, including GPU stats.
• GreenWithEnvy (GWE): Tailored for NVIDIA GPUs, it allows for overclocking and monitoring.

These tools provide an accessible way for users to monitor their GPU’s performance and workload, catering to a wide range of GPU brands and models.

Advanced Techniques for GPU Monitoring

Using nvidia-smi for Detailed Insights

The nvidia-smi command is a powerful tool for NVIDIA GPU users, offering detailed insights into GPU performance and usage. Beyond basic monitoring, nvidia-smi allows users to:

• Track GPU utilization and memory usage
• Set application clocks and power limits
• Monitor temperature and system health

For advanced monitoring, use:

nvidia-smi -q -d PERFORMANCE

This command provides a detailed report on the performance metrics of NVIDIA GPUs, offering deep insights into how the GPU is being utilized in real-time.

Monitoring with vgaswitcheroo

Linux systems with both integrated and discrete GPUs can benefit from vgaswitcheroo, a feature that allows users to switch between GPUs. To check which GPU is active, access the vgaswitcheroo directory:

cat /sys/kernel/debug/vgaswitcheroo/switch

This command displays the status of each GPU, indicating whether it’s on or off. vgaswitcheroo is particularly useful for systems aiming to optimize power consumption by switching between integrated and discrete GPUs.

Checking GPU Utilization with lsof

To determine which processes are utilizing NVIDIA GPUs, lsof can be a valuable command. By listing open files associated with NVIDIA devices, users can identify active processes. Execute:

sudo lsof /dev/nvidia*

This command lists all processes currently using NVIDIA GPU devices, providing insights into which applications are leveraging GPU resources. It’s an effective way to monitor GPU utilization, especially in multi-user environments or when diagnosing performance issues.

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