linux-kernel - RE: [PATCH v11 10/23] x86/resctrl: Remove MSR reading of event configuration value

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Message-ID: <SJ1PR11MB6083C234656AF934E41A7BA8FCF62@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Thu, 6 Feb 2025 00:51:23 +0000
From: "Luck, Tony" <tony.luck@...el.com>
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Subject: RE: [PATCH v11 10/23] x86/resctrl: Remove MSR reading of event
 configuration value

> This new arch API has sharp corners because of asymmetry of where resctrl
> runs the arch function. I do not think it is required to change this since we
> can only speculate about how this may be used in the future but I do think
> it will be helpful to add comments that highlight:
>
> resctrl_arch_mon_event_config_get() ->  May run on CPU that does not belong to domain.
> resctrl_arch_mon_event_config_set() ->  Runs on CPU that belongs to domain.

Here's a vague data point about the future to help with speculation.

I have something coming along the pipeline that also can run on any CPU.

I am contemplating a flag in the rdt_resource structure (in appropriate substructure
resctrl_cache/resctrl_membw) to indicate "domain" vs. "any" for operations.

Would something like that be useful here?

-Tony