linux-kernel - Re: [PATCH v12 12/26] x86/resctrl: Add data structures and definitions for ABMC assignment

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Message-ID: <37ec1d51-1180-474d-9487-38dd49988c59@amd.com>
Date: Wed, 16 Apr 2025 10:43:16 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, tony.luck@...el.com,
 peternewman@...gle.com
Cc: corbet@....net, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
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 rostedt@...dmis.org, ardb@...nel.org, gregkh@...uxfoundation.org,
 daniel.sneddon@...ux.intel.com, jpoimboe@...nel.org,
 alexandre.chartre@...cle.com, pawan.kumar.gupta@...ux.intel.com,
 thomas.lendacky@....com, perry.yuan@....com, seanjc@...gle.com,
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 maciej.wieczor-retman@...el.com, eranian@...gle.com
Subject: Re: [PATCH v12 12/26] x86/resctrl: Add data structures and
 definitions for ABMC assignment

Hi Reinette,

On 4/15/25 11:30, Reinette Chatre wrote:
> Hi Babu,
> 
> On 4/14/25 1:30 PM, Moger, Babu wrote:
>> Hi Reinette,
>>
>> On 4/11/25 16:01, Reinette Chatre wrote:
>>> Hi Babu,
>>>
>>> On 4/3/25 5:18 PM, Babu Moger wrote:
>>>> The ABMC feature provides an option to the user to assign a hardware
>>>> counter to an RMID, event pair and monitor the bandwidth as long as the
>>>> counter is assigned. The bandwidth events will be tracked by the hardware
>>>> until the user changes the configuration. Each resctrl group can configure
>>>> maximum two counters, one for total event and one for local event.
>>>>
>>>> The ABMC feature implements an MSR L3_QOS_ABMC_CFG (C000_03FDh).
>>>> Configuration is done by setting the counter id, bandwidth source (RMID)
>>>> and bandwidth configuration supported by BMEC (Bandwidth Monitoring Event
>>>> Configuration).
>>>
>>> Apart from the BMEC optimization in patch #1 and patch #2 this is the
>>> first and only mention of BMEC dependency I see in this series while I do
>>> not see implementation support for this. What am I missing?
>>>
>>
>> My mistake. I should have corrected it.  How about this?
>>
>> "The ABMC feature implements an MSR L3_QOS_ABMC_CFG (C000_03FDh).
>> ABMC counter assignment is done by setting the counter id, bandwidth
>> source (RMID) and bandwidth configuration. Users will have the option to
>> change the bandwidth configuration using resctrl interface which will be
>> introduced later in the series."
>>
> 
> Please just stick to what this patch does. The part starting with "Users will ..."
> can cause confusion. To support what bandwidth configuration means the description
> can point to existing definitions in include/linux/resctrl_types.h without needing
> to mention BMEC.
> 
Sure. Sounds good.
-- 
Thanks
Babu Moger