linux-kernel - Re: [PATCH 0/2] x86/resctrl: Support wider MBM counters

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Message-ID: <f1820861-9ecb-d685-be3d-accd0047126d@intel.com>
Date:   Thu, 23 Apr 2020 09:40:27 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     tglx@...utronix.de, fenghua.yu@...el.com, bp@...en8.de,
        tony.luck@...el.com
Cc:     kuo-lang.tseng@...el.com, mingo@...hat.com, babu.moger@....com,
        hpa@...or.com, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] x86/resctrl: Support wider MBM counters

Hi Thomas and Borislav,

On 4/1/2020 10:51 AM, Reinette Chatre wrote:
> Memory Bandwidth Monitoring (MBM) is an Intel Resource Director
> Technology (RDT) feature that tracks Total and Local bandwidth
> generated which misses the L3 cache.
> 
> The original Memory Bandwidth Monitoring (MBM) architectural
> definition defines counters of up to 62 bits and the first-generation
> MBM implementation uses 24 bit counters. Software is required to poll
> at 1 second or faster to ensure that data is retrieved before a counter
> rollover occurs more than once under worst conditions.
> 
> As system bandwidths scale the software requirement is maintained with
> the introduction of a per-resource enumerable MBM counter width.
> 
> This series adds support for the new enumerable MBM counter width.
> 
> Details about the feature can be found in Chapter 9 of the most
> recent Intel ISE available from
> https://software.intel.com/sites/default/files/managed/c5/15/architecture-instruction-set-extensions-programming-reference.pdf
> 
> Reinette Chatre (2):
>   x86/resctrl: Maintain MBM counter width per resource
>   x86/resctrl: Support CPUID enumeration of MBM counter width
> 
>  arch/x86/include/asm/processor.h          |  1 +
>  arch/x86/kernel/cpu/common.c              |  5 +++++
>  arch/x86/kernel/cpu/resctrl/ctrlmondata.c |  8 ++++---
>  arch/x86/kernel/cpu/resctrl/internal.h    | 15 ++++++++++---
>  arch/x86/kernel/cpu/resctrl/monitor.c     | 27 ++++++++++++++++-------
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c    |  2 +-
>  6 files changed, 43 insertions(+), 15 deletions(-)
> 


Would it be possible to consider this for inclusion in v5.8?

Thank you

Reinette

ps. Upon your consideration I am planning to follow up with same
the question for the next resctrl new feature series available
at:https://lore.kernel.org/lkml/cover.1586801373.git.reinette.chatre@intel.com/

You could view outstanding resctrl changes at branch resctrl/next of
https://github.com/rchatre/linux.git