Re: [linus:master] [sched/fair] 79104becf4: stress-ng.resched.ops_per_sec 44.6% regression

[Peter Zijlstra]

On Thu, Dec 11, 2025 at 10:21:15PM +0800, kernel test robot wrote:
> 
> 
> Hello,
> 
> kernel test robot noticed a 44.6% regression of stress-ng.resched.ops_per_sec on:
> 
> 
> commit: 79104becf42baeeb4a3f2b106f954b9fc7c10a3c ("sched/fair: Forfeit vruntime on yield")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

After nearly 2 decades of telling people that using yield() is UB
(except in the Real-Time cases where it is well defined), I'm >.< close
to not caring about this.

IIRC this benchmark is literally something like running yield() in a
loop, so boohoo. I'll look when there's a real workload that has a
problem.

> [still regression on linus/master      cfd4039213e7b5a828c5b78e1b5235cac91af53d]
> [still regression on linux-next/master 82bcd04d124a4d84580ea4a8ba6b120db5f512e7]

What's with the still? AFAIK this is the first report of this.