Re: [linus:master] [sched] 96d1610e0b: will-it-scale.per_process_ops 2.8% regression

[Peter Zijlstra]

On Fri, Apr 24, 2026 at 03:10:07PM +0800, kernel test robot wrote:
> 
> 
> Hello,
> 
> kernel test robot noticed a 2.8% regression of will-it-scale.per_process_ops on:
> 
> 
> commit: 96d1610e0b20b5a627773874b4514ae922ad98f6 ("sched: Optimize hrtimer handling")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> 
> [still regression on linus/master      1d51b370a0f8f642f4fc84c795fbedac0fcdbbd2]
> [still regression on linux-next/master 936c21068d7ade00325e40d82bfd2f3f29d9f659]
> [still regression on fix commit        eef9f648fb0e92618041f019d4bdcf7ae17cb743]
> 
> testcase: will-it-scale
> config: x86_64-rhel-9.4
> compiler: gcc-14
> test machine: 48 threads 2 sockets Intel(R) Xeon(R) CPU E5-2697 v2 @ 2.70GHz (Ivy Bridge-EP) with 64G memory
> parameters:

So this commit has lived in private trees (tglx and mine), has been in
tip, in next etc. *WHY* do we only get this report now?

This isn't the first time I see a regression report after things have
hit Linus' tree. This is starting to get really annoying. The point of
having this robot was to catch issues *before* they hit Linus, no?

That said, looking back at will-it-scale reports, 2.8 seems to be pretty
much in the noise range, no?