Re: [PATCH v2 25/26] selftests/resctrl: Get domain id from cache id

[Reinette Chatre]

Hi Ilpo,

On 11/20/2023 3:13 AM, Ilpo Järvinen wrote:
> Domain id is acquired differently depending on CPU. AMD tests use id
> from L3 cache, whereas CPUs from other vendors base the id on topology
> package id. In order to support L2 CAT test, this has to be
> generalized.
> 
> The driver side code seems to get the domain ids from cache ids so the
> approach used by the AMD branch seems to match the kernel-side code. It
> will also work with L2 domain IDs as long as the cache level is
> generalized.
> 
> Using the topology id was always fragile due to mismatch with the
> kernel-side way to acquire the domain id. It got incorrect domain id,
> e.g., when Cluster-on-Die (CoD) is enabled for CPU (but CoD is not well
> suited for resctrl in the first place so it has not been a big issue if
> tests don't work correctly with it).
> 
> Taking all the above into account, generalize acquiring the domain id
> by taking it from the cache id and do not hard-code the cache level.
> 
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>

Reinette