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