The patch by Linux kernel developer Mike Galbraith adds a mere 233 lines of code to the kernel's scheduler, but it cuts desktop latency down by a factor of ten. That's impressive it's almost like getting a new computer.
In the Linux Kernel Mailing List, Linus Torvalds himself praised the performance boost he gets from the patch. Torvalds wrote:
I'm also very happy with just what it does to interactive performance. Admittedly, my "testcase" is really trivial (reading email in a web-browser, scrolling around a bit, while doing a "make -j64" on the kernel at the same time), but it's a test-case that is very relevant for me. And it is a _huge_ improvement.
It's an improvement for things like smooth scrolling around, but what I found more interesting was how it seems to really make web pages load a lot faster. Maybe it shouldn't have been surprising, but I always associated that with network performance. But there's clearly enough of a CPU load when loading a new web page that if you have a load average of 50+ at the same time, you _will_ be starved for CPU in the loading process, and probably won't get all the http requests out quickly enough.
So I think this is firmly one of those "real improvement" patches. Good job. Group scheduling goes from "useful for some specific server loads" to "that's a killer feature".The scheduler patch works by simply enabling the system to automatically create task groups per TTY an archaic term that comes the days when Teletype style terminals were used for computer interfaces. In Linux and Unix, TTY are used for real and virtual input/output devices.
You wouldn't think that such a simple patch could make such a big difference, but the proof is there. I've tried it myself and I was impressed. You can see for it yourself in these before- and after-the-patch Phoronix videos.