RE: [PATCH 4/4] selftests/resctrl: Adjust SNC support messages

From: "Luck, Tony" <tony.luck@intel.com>
To: "Wieczor-Retman, Maciej" <maciej.wieczor-retman@intel.com>
Cc: "Yu, Fenghua" <fenghua.yu@intel.com>,
	"Chatre, Reinette" <reinette.chatre@intel.com>,
	Shuah Khan <shuah@kernel.org>,
	"james.morse@arm.com" <james.morse@arm.com>,
	"ilpo.jarvinen@linux.intel.com" <ilpo.jarvinen@linux.intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>
Subject: RE: [PATCH 4/4] selftests/resctrl: Adjust SNC support messages
Date: Thu, 7 Mar 2024 17:18:11 +0000	[thread overview]
Message-ID: <SJ1PR11MB60830E546B3D575B01D37104FC202@SJ1PR11MB6083.namprd11.prod.outlook.com> (raw)
In-Reply-To: <o6va7b7rc3q46olsbscav7pla4hxot2g6xhctflhmf64pj5hpx@56vtbg3yyquy>

>>If so, what should it be named? "snc_ways" as a kernel variable was
>>later replaced by "snc_nodes_per_l3_cache". Is that a good filename?
>
> "snc_nodes_per_l3_cache" seems okay to me.
>
> And I understand that the file content would show SNC mode and the presence or
> absence of this file would tell if kernel supports SNC?

Yes. The existence of the file indicates the kernel is SNC aware.

The value read from the file would give the number of nodes per L3 (obviously :-) )

SNC not supported by this platform or not enabled:

$ cat /sys/fs/resctrl/info/L3_mon/ snc_nodes_per_l3_cache
1

SNC2 enabled:

$ cat /sys/fs/resctrl/info/L3_mon/ snc_nodes_per_l3_cache
2

etc.

-Tony