Re: [PATCH][RFC] make cpu_sibling_map a cpumask_t

[Nick Piggin]

Anton Blanchard wrote:

> > I'm not aware of any reason why the kernel should not become generally
> > SMT aware. It is sufficiently different to SMP that it is worth
> > specialising it, although I am only aware of P4 and POWER5 implementations.
>
> I agree, SMT is likely to become more popular in the coming years.
>
>
> > I have an alternative to Ingo's HT scheduler which basically does
> > the same thing. It is showing a 20% elapsed time improvement with a
> > make -j3 on a 2xP4 Xeon (4 logical CPUs).
> >
> > Before Ingo's is merged, I would like to discuss the pros and cons of
> > both approaches with those interested. If Ingo's is accepted I should
> > still be able to port my other SMP/NUMA improvements on top of it.
>
> Sounds good, have you got anything to test? I can throw it on a POWER5.

It would be great to get some testing on another architecture.

I don't have an architecture independant way to build SMT scheduling
descriptions, although with the cpu_sibling_map change, you can copy
and paste the code for the P4 if you are able to build a cpu_sibling_map.

I'll just have to add a some bits so SMT and NUMA work together which
I will be unable to test. I'll get back to you with some code.


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