On Mon, 8 Dec 2003, Nick Piggin wrote:

> It turns the cpu_sibling_map array from an array of cpus to an array
> of cpumasks. This allows handling of more than 2 siblings, not that
> I know of any immediate need.
>
> I think it generalises cpu_sibling_map sufficiently that it can become
> generic code. This would allow architecture specific code to build the
> sibling map, and then Ingo's or my HT implementations to build their
> scheduling descriptions in generic code.
>
> 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.

Generally i agree, it's fairly unintrusive and appears to clean up some
things. Perhaps Andrew will take it a bit later after release.

> P.S.
> 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).

-j3 is an odd number, what does -j4, -j8, -j16 look like?