I don't follow kernel development extremely closely, but it fascinates me that people are still actively working on the kernel's scheduler and achieving a "huge improvement" like this.
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.
I remember reading something about an anesthesiologist who got into hacking the scheduler targeting desktop use cases. He generally said that the scheduler gets a lot more attention from people who care more about server work loads and such. He had his own custom kernel patches that people used to get directly from him that weren't in the mainstream kernel -- This was before the era of multi-core, but people said his scheduler had better responsiveness than the default one.
