linux-kernel - Re: [PATCH 00/24] x86/resctrl: Merge the CDP resources

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Message-ID: <04fdd774-99e0-4b99-2d70-06cfd0ab3be6@intel.com>
Date:   Mon, 16 Nov 2020 09:54:06 -0800
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     James Morse <james.morse@....com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        shameerali.kolothum.thodi@...wei.com,
        Jamie Iles <jamie@...iainc.com>,
        D Scott Phillips OS <scott@...amperecomputing.com>
Subject: Re: [PATCH 00/24] x86/resctrl: Merge the CDP resources

Hi James,

On 10/30/2020 9:10 AM, James Morse wrote:
> MPAM has an equivalent feature to CDP, but its a property of the CPU,
> not the cache. Resctrl needs to have x86's odd/even behaviour, as that
> its the ABI, but this isn't how the MPAM hardware works. It is entirely
> possible that an in-kernel user of MPAM would not be using CDP, whereas
> resctrl is.

The above seems to distinguish between "in-kernel user of MPAM" and 
resctrl (now obtaining support for MPAM). Could you please provide more 
details on the "in-kernel user of MPAM" and elaborate on how these two 
usages are expected to interact with MPAM concurrently?

Thank you

Reinette