Up to this point the OpenGL performance of the Nouveau Linux driver has been quite admirable considering that it's largely a community project and it's developed without NVIDIA's help but by clean-room reverse-engineering their binary-only Linux driver.
With the Linux 2.6.39 kernel, and the latest DRM changes just pushed into the Linux 2.6 Git development tree two days ago, there are more Nouveau kernel driver enhancements. In particular, the two key features for the Nouveau driver that will be new in the 2.6.39 kernel is page-flipping and z-compression.
It was just in the Linux 2.6.38 kernel that KMS/DRI2 page-flipping for the Radeon driver was enabled, which led to massive performance improvements. With the Nouveau driver, KMS page-flipping is obviously another huge performance win and it also allows for tear-free screen updating. With page-flipping, a pointer is simply flipped between the front and back-buffers where otherwise the data is being copied to/from the front/back-buffer.
An article will be published on Monday that looks at the Nouveau performance in more detail, but based upon the major performance boosts found, here's a sneak preview. But, if you follow me on Twitter you should already have known about fantastic Nouveau driver performance (of course, follow me to learn about future tests and by doing so you might also win some copies of Unigine's new Linux game).
While full details will come on Monday, here's a preview of one of the graphs that illustrate the improvements quite clearly.
With Nexuiz, which is one of the more demanding open-source first person shooters with a native Linux client, low-end NVIDIA GPUs are nearly as fast -- or faster -- with the Nouveau driver on the Linux 2.6.39 kernel as they are with NVIDIA's proprietary driver. The Phoronix Test Suite runs Nexuiz with the high-quality game settings, which includes the use of GLSL shaders, etc. This is impressive and with the Radeon driver it's not yet beating the Catalyst driver on newer hardware generations (with Radeon X1000 series GPUs it comes mighty close, however).
With the Linux 2.6.39 kernel, xf86-video-nouveau Git, and Mesa 7.11-devel Nouveau Git, this isn't the only test either where the Nouveau driver is finally pushing serious performance competition to the NVIDIA blob. Other results on Monday will show other wins.
While Nouveau is doing great with the GeForce 8500GT, GeForce 9500GT, and GeForce GT 220, when moving to faster NVIDIA GPUs, Nouveau is currently lacking some crucial elements as the NVIDIA binary driver there still running significantly faster.
Stay tuned for some very interesting results and the complete write-up on Monday and "Prost!" (cheers) to the Nouveau developers on hitting an impressive milestone for a reverse-engineered, community project. For Nouveau users, the Linux 2.6.39 kernel is a must-have (for those of you planning to use Ubuntu 11.04 / Fedora 15, however, you'll need to upgrade the kernel manually).