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I have installed Nvidia proprietary driver on Ubuntu 19.10.
In the Prime Profiles section, there are three options:
* NVIDIA (Performance Mode)
* NVIDIA On-Demand
* Intel (Power Saving Mode)
First and last options are quite obvious, But I don't know how the second option works. How it detects which application needs NVIDIA driver and which doesn't?
From: Part I. Installation and Configuration Instructions
PRIME render offload is the ability to have an X screen rendered by one GPU, but choose certain applications within that X screen to be rendered on a different GPU. This is particularly useful in combination with dynamic power management to leave an NVIDIA GPU powered off, except when it is needed to render select performance-sensitive applications.
The GPU rendering the majority of the X screen is known as the "sink", and the GPU to which certain application rendering is "offloaded" is known as the "source". The render offload source produces content that is presented on the render offload sink. The NVIDIA driver can function as a PRIME render offload source, to offload rendering of GLX+OpenGL or Vulkan, presenting to an X screen driven by the xf86-video-modesetting X driver.
NVIDIA's PRIME render offload support requires the following git commits in the X.Org X server:
7f962c70 - xsync: Add resource inside of SyncCreate, export SyncCreate
37a36a6b - GLX: Add a per-client vendor mapping
8b67ec7c - GLX: Use the sending client for looking up XID's
56c0a71f - GLX: Add a function to change a clients vendor list
b4231d69 - GLX: Set GlxServerExports::{major,minor}Version
As of this writing, these commits are only in the master branch of the X.Org X server, and not yet in any official X.Org X server release.
Ok I finally figured it out.
As this moment, it appears that NVIDIA can do offload rendering for OpenGL and Volkan apps.
In order to enable this offload rendering, you have to put the Prime profile on "On-Demand", then for volkan offloading you have to put this variable inside your etc/environment file:
__NV_PRIME_RENDER_OFFLOAD=1
For OpenGL apps, you have to put these variables:
__NV_PRIME_RENDER_OFFLOAD=1
__GLX_VENDOR_LIBRARY_NAME=nvidia
After a restart, it will start render offloading.
In order to check which graphic card is being used, you can enter the following command in terminal:
glxinfo | grep vendor
as extension to Md Narimani answer: i can confirm this is actually working for me on kubuntu 19.10 with nvidia driver version 440
some background info can be found at Chapter 34. PRIME Render Offload
you can set the 'on-demand' option also in the GUI: Nvidia X Server Settings - PRIME Profiles: NVIDIA On-Demand
then restart.
then you can start your application with the environment variables also directly from commandline - so you can switch GPUs as needed:
stefan@stefan-Zen:~$ glxheads :0
Name: :0
Display: 0x556081a45d40
Window: 0x7000002
Context: 0x556081a64a70
GL_VERSION: 3.0 Mesa 19.2.8
GL_VENDOR: Intel Open Source Technology Center
GL_RENDERER: Mesa DRI Intel(R) UHD Graphics 630 (Coffeelake 3x8 GT2)
stefan@stefan-Zen:~$ __NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia glxheads :0
Name: :0
Display: 0x55f6dd9097a0
Window: 0x7000002
Context: 0x55f6dd944878
GL_VERSION: 4.6.0 NVIDIA 440.64
GL_VENDOR: NVIDIA Corporation
GL_RENDERER: GeForce RTX 2060/PCIe/SSE2
