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SubjectRe: [patch V3 23/40] x86/cpu: Provide cpu_init/parse_topology()
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Hello Thomas,

On 8/2/2023 3:51 PM, Thomas Gleixner wrote:
>
> [..snip..]
>
> +static void topo_set_max_cores(struct topo_scan *tscan)
> +{
> + /*
> + * Bug compatible for now. This is broken on hybrid systems:
> + * 8 cores SMT + 8 cores w/o SMT
> + * tscan.dom_ncpus[TOPO_CORE_DOMAIN] = 24; 24 / 2 = 12 !!
> + *
> + * Cannot be fixed without further topology enumeration changes.
> + */
> + tscan->c->x86_max_cores = tscan->dom_ncpus[TOPO_CORE_DOMAIN] >>
> + x86_topo_system.dom_shifts[TOPO_SMT_DOMAIN];
> +}
>

In Documentation/arch/x86/topology.rst, "cpuinfo_x86.x86_max_cores" is
described as "The number of cores in a package". In which case,
shouldn't the above be:

tscan->c->x86_max_cores = tscan->dom_ncpus[TOPO_PKG_DOMAIN] >>
x86_topo_system.dom_shifts[TOPO_SMT_DOMAIN];

since, with extended topology, there could be other higher domains and
dom_ncpus[TOPO_CORE_DOMAIN] >> dom_shifts[TOPO_SMT_DOMAIN] should only
give number of cores within the next domain (TOPO_MODULE_DOMAIN).

Am I missing something here?

--
Thanks and Regards,
Prateek

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