Messages in this thread | | | Date | Wed, 21 Nov 2012 18:20:46 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 00/27] Latest numa/core release, v16 |
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* Ingo Molnar <mingo@kernel.org> 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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