Re: [PATCH v8 0/8] Add support for Sub-NUMA cluster (SNC) systems

[Reinette Chatre]

Tony,

On 10/3/2023 2:30 PM, Tony Luck wrote:
> The Sub-NUMA cluster feature on some Intel processors partitions
> the CPUs that share an L3 cache into two or more sets. This plays
> havoc with the Resource Director Technology (RDT) monitoring features.
> Prior to this patch Intel has advised that SNC and RDT are incompatible.
> 
> Some of these CPU support an MSR that can partition the RMID
> counters in the same way. This allows for monitoring features
> to be used (with the caveat that memory accesses between different
> SNC NUMA nodes may still not be counted accurately.

Almost. For reference:
https://lore.kernel.org/lkml/e350514e-76ed-14ea-3e74-c0852658182f@xxxxxxxxx/

No need to send a new series just for this, but this series does find
itself at the back of my queue.

> Note that this patch series improves resctrl reporting considerably
> on systems with SNC enabled, but there will still be some anomalies
> for processes accessing memory from other sub-NUMA nodes.
> 
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>

Reinette