tl;dr large gaming performance over stock CPU scheduler when there is 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.