Daniel Vetter, the current maintainer of Intel's "-next" Git tree for their open-source DRM driver, has issued a new pull request to David Airlie for pulling in the latest bits into his DRM subsystem "-next" tree. This is what will ultimately go into the Linux 3.4 kernel as soon as the next merge window is open. His pull request can be found on the dri-devel mailing list.
There's some interesting work building up for Linux 3.4 when it concerns Intel's Direct Rendering Manager driver, namely there's interlaced mode support, improved error state work, a "pile of minor patches", and two performance-related items.
PPGTT is short for Per-process Graphics Translation Table and allows each graphics process to map its own region of graphics memory.As PPGTTs are cacheable and each process having its own region of memory can avoid potential clashing, the PPGTT work leads to performance improvements.
The other item that can enhance performance for Intel graphics in the Linux 3.4 kernel is swizzling support. Again, this is just a Sandy Bridge and Ivy Bridge feature.
Coming up soon will be benchmarks to look to see how this latest open-source Intel work affects the Sandy Bridge graphics performance. It's also making me rather impatient to see shipping Ivy Bridge hardware and how interesting its performance will be.
Besides the PPGTT and swizzling support, enabling RC6 support in their kernel driver also leads to significant performance improvements. This should be in place for the Linux 3.4 kernel as well assuming there's no other fallout from faulty Sandy Bridge systems not being able to handle the RC6 power-savings feature.
As far as where the Intel Sandy Bridge Linux graphics performance is at right now, read Intel Sandy Bridge Shines With Mesa 8.0. You can also see how the Intel Sandy Bridge performance compares to Mac OS X 10.8, the new "Mountain Lion" release coming out this summer from Apple.