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

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Message-ID: <a58bd6f6-f5a7-4f3d-ba2a-b45be09b3c3a@intel.com>
Date: Tue, 15 Apr 2025 09:30:23 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: <babu.moger@....com>, <tony.luck@...el.com>, <peternewman@...gle.com>
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Subject: Re: [PATCH v12 12/26] x86/resctrl: Add data structures and
 definitions for ABMC assignment

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.

Reinette