Re: [patch V4 24/41] x86/cpu: Provide cpu_init/parse_topology()

Peter Zijlstra
2023-09-15T11:55:19Z

On Tue, Aug 29, 2023 at 08:46:14AM +0530, K Prateek Nayak wrote:
> Hello Arjan,
>
> On 8/28/2023 8:04 PM, Arjan van de Ven wrote:
> > On 8/28/2023 7:28 AM, K Prateek Nayak wrote:
> >>>     - Are these really different between AMD and Intel or is this some
> >>>       naming convention issue which needs to be resolved?
> >>     They do have different characteristics since, on Sapphire
> >>     Rapids, the LLC is at a socket boundary despite having multiple
> >>     tiles. (Please correct me if I'm wrong, I'm going off of
> >>     llc_id shared in this report by Qiuxu Zhuo -
> >>     https://lore.kernel.org/all/20230809161219.83084-1-qiuxu.zhuo@intel.com/)
> >>
> >
> > Sapphire reports itself as 1 tile though (since logically it is) as far as I know
> >
>
> I believe there are some variants with multiple tiles, at least the
> following press-release suggests that:
>
> https://www.intc.com/news-events/press-releases/detail/1598/intel-launches-4th-gen-xeon-scalable-processors-max-series
>
> specifically "... combining up to four Intel 7-built tiles on a single
> package, connected using Intel EMIB ...". Perhaps the one from Qiuxu
> Zhuo's report does not contain multiple tiles.

I think what Arjan was saying that despite them being build using
multipe physical tiles, they describe themselves, in the topology leave,
as being a single tile.