From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: kernel test robot <yi1.lai@intel.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
Phil Auld <pauld@redhat.com>,
aubrey.li@linux.intel.com, yu.c.chen@intel.com
Subject: Re: [linus:master] [sched/core] 118a2cf4ce: stress-ng.schedpolicy.ops_per_sec 14.1% regression
Date: Fri, 23 Oct 2026 19:00:23 +0200 [thread overview]
Message-ID: <20261023170023.GY2823843@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <b39cd288-9133-40e1-b27d-d8ef3973b37c@paulmck-laptop>
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@intel.com>
> > | Closes: https://lore.kernel.org/oe-lkp/202610231954.51716452-lkp@intel.com
>
> 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.
next prev parent reply other threads:[~2026-10-23 17:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-23 11:49 kernel test robot
2026-10-23 16:14 ` Paul E. McKenney
2026-10-23 17:00 ` Peter Zijlstra [this message]
2026-10-23 18:51 ` Paul E. McKenney
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