linux-kernel - Re: [PATCH v11 7/8] x86/resctrl: Sub NUMA Cluster detection and enable

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Message-ID: <c6982c26-738b-43fc-a2d6-35fa7cf2c70c@intel.com>
Date:   Mon, 20 Nov 2023 14:24:15 -0800
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghua.yu@...el.com>,
        "Peter Newman" <peternewman@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        "Shuah Khan" <skhan@...uxfoundation.org>, <x86@...nel.org>
CC:     Shaopeng Tan <tan.shaopeng@...itsu.com>,
        James Morse <james.morse@....com>,
        Jamie Iles <quic_jiles@...cinc.com>,
        Babu Moger <babu.moger@....com>,
        Randy Dunlap <rdunlap@...radead.org>,
        <linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <patches@...ts.linux.dev>
Subject: Re: [PATCH v11 7/8] x86/resctrl: Sub NUMA Cluster detection and
 enable

Hi Tony,

On 11/9/2023 3:09 PM, Tony Luck wrote:
> There isn't a simple hardware bit that indicates whether a CPU is
> running in Sub NUMA Cluster (SNC) mode. Infer the state by comparing
> the ratio of NUMA nodes to L3 cache instances.
> 
> When SNC mode is detected, reconfigure the RMID counters by updating
> the MSR_RMID_SNC_CONFIG MSR on each socket as CPUs are seen.
> 
> Clearing bit zero of the MSR divides the RMIDs and renumbers the ones
> on the second SNC node to start from zero.
> 
> Reviewed-by: Peter Newman <peternewman@...gle.com>
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---

(note ordering of commit tags)

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

Reinette