* Ingo Molnar [off-list ref] wrote:

So because I did not have an old-glibc system like David's, I 
did not know the actual page fault rate. If it is high enough 
then nonlinear effects might cause such effects.

This is an entirely valid line of inquiry IMO.

Btw., when comparing against 'mainline' I routinely use a 
vanilla kernel that has the same optimization applied. (first I 
make sure it's not a regression to vanilla.)

I do that to factor out the linear component of the independent 
speedup: it would not be valid to compare vanilla against 
numa/core+optimization, but the comparison has to be:

       vanilla + optimization
  vs.
     numa/core + optimization

I did that with last night's numbers as well.

So any of this can only address a regression if a non-linear 
factor is in play.

Since I have no direct access to a regressing system I have to 
work with the theories that I can think of: one had a larger 
effect, the other had a smaller effect, the third one had no 
effect on David's system.

How would you have done it instead?

Thanks,

	Ingo

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