Pretty much all of the performance enhancement in the kernel has been toward server-type high-throughput applications. This was mainly because subjective things like jutter and interactivity lag are really hard to measure objectively (using existing performance benchmarks), and it's really hard to optimize for something when you have no benchmarks and no regression tests. Desktop-style interactivity improvements have been advancing only recently. The cgroups feature has actually been available in the kernel for some time, but distros weren't using it. This new patch sort of auto-configures cgroups per-TTY.
