Google has been using Mesa/Gallium3D drivers for use on their Intel-powered Chromebooks. Google had invested heavily in the Intel Gallium3D driver for use on their older Chromebooks, but now they are starting to push more of their Mesa/Gallium3D changes that have been building up in months past.
Published today on the mailing list by Google's Frank Henigman is an LLVM compiler cache for Gallium3D. "This works (has been in Chrome OS for a while) but only for vertex shaders, not geometry shaders nor llvmpipe...I don't know how much other apps care but it's a big win for Chrome because just opening an empty tab recompiles some shaders and takes hundreds of milliseconds on a low-end chromebook. Revisiting a page with a bunch of shaders is seconds faster....My cache comes in before generating LLVM source however, thus should have bigger savings than can be realized at the LLVM level."
Frank also posted per-texture locking support. This work allows uploading textures from one thread concurrently with drawing in another thread, thus a performance benefit.
Another set of patches out of Google recently allows saving about 1MB per texture with LLVM vertex shaders. This memory-saving work has been in Google's patched Mesa version for a while and is now being submitted for possible upstream inclusion.
Overall, it's good to see Google's continued Mesa involvement and furthering the open-source Linux graphics drivers for Chrome OS.