linux-kernel - Re: [PATCH v7 20/24] x86/resctrl: Introduce the interface to switch between monitor modes

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Message-ID: <6df77680-6541-3d77-0680-1d67abdae0c7@amd.com>
Date: Fri, 27 Sep 2024 08:26:19 -0500
From: "Moger, Babu" <bmoger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, babu.moger@....com,
 corbet@....net, fenghua.yu@...el.com, tglx@...utronix.de, mingo@...hat.com,
 bp@...en8.de, dave.hansen@...ux.intel.com
Cc: x86@...nel.org, hpa@...or.com, paulmck@...nel.org, rdunlap@...radead.org,
 tj@...nel.org, peterz@...radead.org, yanjiewtw@...il.com,
 kim.phillips@....com, lukas.bulwahn@...il.com, seanjc@...gle.com,
 jmattson@...gle.com, leitao@...ian.org, jpoimboe@...nel.org,
 rick.p.edgecombe@...el.com, kirill.shutemov@...ux.intel.com,
 jithu.joseph@...el.com, kai.huang@...el.com, kan.liang@...ux.intel.com,
 daniel.sneddon@...ux.intel.com, pbonzini@...hat.com, sandipan.das@....com,
 ilpo.jarvinen@...ux.intel.com, peternewman@...gle.com,
 maciej.wieczor-retman@...el.com, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, eranian@...gle.com, james.morse@....com
Subject: Re: [PATCH v7 20/24] x86/resctrl: Introduce the interface to switch
 between monitor modes

Hi Reinette,

On 9/26/2024 8:51 PM, Reinette Chatre wrote:
> Hi Babu,
> 
> On 9/26/24 12:39 PM, Moger, Babu wrote:
>> On 9/19/24 12:38, Reinette Chatre wrote:
>>> On 9/4/24 3:21 PM, Babu Moger wrote:
> 
>>>> +	  ::
>>>> +
>>>> +	    # echo  "default" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
>>>> +
>>>> +	The MBM event counters will reset when mbm_assign_mode is changed. Moving to
>>>
>>> "will reset" -> "may reset"? Please also be clear on what is meant with "MBM event counter".
>>
>> It "will reset".
>>
> 
> I understand that this is true for the ABMC implementation. My goal with making this vague is
> to not have this reset set in stone if some other implementation behaves differently.

ok.
> 
>>> Note that "counter" has a very specific meaning in this work and after considering that
>>> it is not clear if "MBM event counter will reset" means that the counters are no longer
>>> assigned or if it means that the counts associated with events will be reset.
>>
>> How about
>>
>> "The MBM event counters(mbm_total_bytes and mbm_local_bytes) associated
>> with the event will reset when mbm_assign_mode is changed."
> 
> In the docs "mbm_total_bytes" and "mbm_local_bytes" are termed "events" ... maybe
> "The MBM events (mbm_total_bytes and/or mbm_local_bytes) associated
> counters may reset when mbm_assign_mode is changed."?

Sure.

-- 
- Babu Moger