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

[Nick Piggin <piggin@cyberone.com.au>]

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.