Re: [PATCH 00/27] Latest numa/core release, v16

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> This is an entirely valid line of inquiry IMO.

Btw., what I did was to simply look at David's profile on the 
regressing system and I compared it to the profile I got on a 
pretty similar (but unfortunately not identical and not 
regressing) system. I saw 3 differences:

 - the numa emulation faults
 - the higher TLB miss cost
 - numa/core's failure to handle 4K pages properly

And addressed those, in the hope of one of them making a
difference.

There's a fourth line of inquiry I'm pursuing as well: the node 
assymetry that David and Paul mentioned could have a performance 
effect as well - resulting from non-ideal placement under 
numa/core.

That is not easy to cure - I have written a patch to take the 
node assymetry into consideration, I'm still testing it with 
David's topology simulated on a testbox:

   numa=fake=4:10,20,20,30,20,10,20,20,20,20,10,20,30,20,20,10

Will send the patch out later.

Thanks,

	Ingo
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