While new work is now focused upon Mesa 9.3 / Mesa 10.0 with Mesa 9.2 already having been branched ahead of its planned release next week, there's been plenty of good stuff flowing into Git master and it's worth checking out for Linux desktop enthusiasts and Linux gamers.
One of the most recent performance enhancements for the Intel DRI driver was i965/fs: Optimize IF/MOV/ELSE/MOV/ENDIF to SEL when possible. This patch can dramatically cut down the number of GLSL shader instructions for programs by significant percentages. The commit by Kenneth Graunke noted, "This helps Valve's Source Engine games (max -41.33%), The Cave (max -33.33%), Serious Sam 3 (max -18.64%), Yo Frankie! (max -30.19%), Zen Bound (max -22.22%), GStreamer (max -6.12%), and GLBenchmark 2.7 (max -1.94%)."
A fresh round of Mesa Git benchmarks are forthcoming for all three major Linux graphics hardware vendors.