Mesa and Gallium3D

Gallium3D is the new driver architecture for Mesa. In the X11 overlay you will now find an eselect mesa module, which in conjunction with the live mesa ebuild allows you to switch between classic and gallium.

Of course, this only works for drivers which exist both in a classic and gallium version. At the time of writing these are:
  • i915, i965: The gallium drivers for Intel chipsets are presently inferior to the classic drivers. There is little reason to use them at this time.
  • Radeon r300: The radeong gallium driver works well and has recently surpassed the classic driver in terms of features and performance.
  • Radeon r600: The r600g gallium driver was added to mesa a week ago and does not do anything useful yet.
  • Software renderer: If Mesa was built with the "llvm" USE flag enabled, then the gallium llvmpipe driver will give you much improved performance over the classic software rasterizer. As a tile based renderer it will use multithreading too. However some graphical glitches are still visible.
If you encounter any issues with eselect mesa, feel free to join #gentoo-desktop on freenode or report a bug, prefixing the summary with "[x11 overlay]".

Update: If you had already installed mesa-9999 from the X11 overlay, please rebuild it to ensure proper functioning of the eselect module.