linux-kernel - RE: [PATCH 0/1] fs/resctrl: Show domain CPU list in schema output

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Message-ID: <SJ1PR11MB6083A4A7720723C14F3AE314FCF8A@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Fri, 31 Oct 2025 19:03:15 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: Aaron Tomlin <atomlin@...mlin.com>, "Chatre, Reinette"
	<reinette.chatre@...el.com>, "Dave.Martin@....com" <Dave.Martin@....com>,
	"james.morse@....com" <james.morse@....com>, "babu.moger@....com"
	<babu.moger@....com>, "tglx@...utronix.de" <tglx@...utronix.de>,
	"mingo@...hat.com" <mingo@...hat.com>, "bp@...en8.de" <bp@...en8.de>,
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 0/1] fs/resctrl: Show domain CPU list in schema output

> The current resctrl schemata output provides only the domain ID and value
> (e.g., 0=ffff). This patch updates the schema format to include the
> underlying topology, making it easier for users to correlate the resource
> domain with its assigned logical CPUs.
>
> The output changes from "0=ffff" to "0=ffff,0-15".
>
> Please let me know your thoughts.

1) You'd also need to change the "write" path for the schemata file
(treating the CPU list as read-only).

2) This would break user ABI, so is not going to happen.

Users can see the association between the domain numbers and
CPUs in sysfs.

$ cat /sys/devices/system/cpu/cpu0/cache/index3/id
0
$ cat /sys/devices/system/cpu/cpu0/cache/index3/shared_cpu_list
0-27

Maybe not as convenient as a direct read-out in the schemata file.
But the information is easily accessible.

-Tony