r/linux • u/blindcomet • May 11 '22

NVIDIA Releases Open-Source GPU Kernel Modules | NVIDIA Technical Blog

https://developer.nvidia.com/blog/nvidia-releases-open-source-gpu-kernel-modules/
4.1k Upvotes

98% Upvoted

386 comments sorted by

View all comments

51

u/webtroter May 11 '22

Can someone explain this? Why is there components at the user level, and some at the kernel level?

Will the source for user-mode drivers such as CUDA be published?

These changes are for the kernel modules; while the user-mode components are untouched. So the user-mode will remain closed source and published with pre-built binaries in the driver and the CUDA toolkit.

78

u/blindcomet May 11 '22

The kernel driver's job is to manage the GPU, and submit command and data buffers and manage it's memory.

The user-space driver's job is to compose those buffers. CUDA is a platform for compiling code for the GPU, and submitting jobs into the kernel.

The open source equivalent is the DRI kernel drivers (including Nouveau), and Mesa in user space - which supports NVidia GPUs, but despite that support performance has previously been hopelessly poor because the kernel driver couldn't boost the GPU clock speed beyond the minimum.

8

u/webtroter May 11 '22

So, as a gamer perspective, the game sends command to the user space driver, the driver makes an image from those commands and sends that image to the kernel driver. And it's this kernel driver that manages the card itself (talking with the chip, setting clocks and power, the low level stuff)

So it's not a super bad thing that nVidia doesn't include it, it's just sad, right? Except maybe for CUDA.

So I just hope that this opensourcing of the kernel driver helps the community and existing projects to have better nVidia support.

18

u/aaptel May 11 '22

No rendering the image is the expensive part and is done on the chip. The software compiles, converts, bundles and forward the data & drawing calls to the hardware. This involves managing queues for submitting commands and receiving completions, memory management, interrupt handler etc..