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SubjectRe: [PATCH 1/2] sched/wait: Break up long wake list walk
> > Still, generating such a migration storm would be fairly tricky I think.
> Well, Mel seems to have been unable to generate a load that reproduces
> the long page waitqueues. And I don't think we've had any other
> reports of this either.

It could be that it requires a fairly large system. On large systems
under load a lot of things take much longer, so what's a tiny window on Mel's
system may suddenly be very large, and with much more threads
they have a higher chance of bad interactions anyways.

We only see it on 4S+ today. But systems are always getting larger,
so what's a large system today, will be a normal medium scale system

BTW we also collected PT traces for the long hang cases, but it was
hard to find a consistent pattern in them.


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