Re: [linus:master] [sched/core] 118a2cf4ce: stress-ng.schedpolicy.ops_per_sec 14.1% regression

[Peter Zijlstra]

On Fri, Oct 23, 2026 at 09:14:02AM -0700, Paul E. McKenney wrote:
> On Fri, Oct 23, 2026 at 07:49:20PM +0800, kernel test robot wrote:
> > 
> > 
> > Hello,
> > 
> > kernel test robot noticed a 14.1% regression of stress-ng.schedpolicy.ops_per_sec on:
> > 
> > 
> > commit: 118a2cf4ced60777a2408001e2b4838fed1cea55 ("sched/core: Call wakeup_preempt() for queued tasks during class change") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> > 
> > testcase: stress-ng
> > config: x86_64-rhel-9.4
> > compiler: gcc-14
> > test machine: 224 threads 2 sockets Intel(R) Xeon(R) Platinum 8480CTDX (Sapphire Rapids) with 256G memory
> > parameters:
> > 
> > 	nr_threads: 100%
> > 	testtime: 60s
> > 	test: schedpolicy
> > 	cpufreq_governor: performance
> > 
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <yi1.lai@xxxxxxxxx>
> > | Closes: https://lore.kernel.org/oe-lkp/202610231954.51716452-lkp@xxxxxxxxx
> 
> This regression is not a good thing, but this commit is fixing a real bug.

I think I have a patch somewhere stuck in my review queue for -rc1 that
might help with this:

  https://patch.msgid.link/CANGjgdmNCfm%3DSctvKZ44y8b5n8t_JSp4meX%3DDKGnG74B3g1vVw%40mail.gmail.com

If not, too bad, correctness first and all that.