tl;dr large gaming performance over stock CPU scheduler when there is a heavy CPU task running in background
Obviously, they only tested one game and it may not apply everywhere or hurt performance/latency in some cases.
One thing I wasn’t aware of is that sched-ext/ePBF supports changing CPU schedulers on-the-fly, which takes away one of the downsides of third-party schedulers. I.e. you can use the stock scheduler most of the time, but then switch to a third party scheduler for specific workloads. So less of a downside risk.
Finally, none of this is merged yet (including sched-ext) so it’s out of reach if you are just using the stock kernel.
Linux has quite a few schedulers. The performance of this new one is almost certainly a result of different algorithms used, not an effect of refactoring the existing ones, nor the language it’s written in.
I don’t think I’ll dig in to the code just now, but if it turns out to have much practical value, perhaps we’ll eventually see an article about the design.
Yeah, a scheduler just decided which processes get CPU time and takes up a very small part of total execution time. So yeah, I wouldn’t expect compiler optimizations to matter much.