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SubjectRe: [mm/page_alloc] f26b3fa046: netperf.Throughput_Mbps -18.0% regression
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On Tue, 2022-05-10 at 11:05 -0700, Linus Torvalds wrote:
> [ Adding locking people in case they have any input ]
>
> On Mon, May 9, 2022 at 11:23 PM ying.huang@intel.com
> <ying.huang@intel.com> wrote:
> >
> > >
> > > Can you point me to the regression report? I would like to take a look,
> > > thanks.
> >
> > https://lore.kernel.org/all/1425108604.10337.84.camel@linux.intel.com/
>
> Hmm.
>
> That explanation looks believable, except that our qspinlocks
> shouldn't be spinning on the lock itself, but spinning on the mcs node
> it inserts into the lock.

The referenced regression report is very old (in Feb 2015 for 3.16-
3.17). The ticket spinlock was still used at that time. I believe that
things become much better after we used qspinlock. We can test that.

Best Regards,
Huang, Ying

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