linux-kernel - Re: [PATCH v6 18/22] x86/resctrl: Report "Unassigned" for MBM events in ABMC mode

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Message-ID: <209b58ab-3885-47a2-b1dc-ecf854fb621d@amd.com>
Date: Wed, 21 Aug 2024 12:30:10 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.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 v6 18/22] x86/resctrl: Report "Unassigned" for MBM events
 in ABMC mode

Hi Reinette,

On 8/16/24 16:42, Reinette Chatre wrote:
> Hi Babu,
> 
> On 8/6/24 3:00 PM, Babu Moger wrote:
>> In ABMC mode, the hardware counter should be assigned to read the MBM
>> events.
>>
>> Report "Unassigned" in case the user attempts to read the events without
>> assigning the counter.
>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
>> v6: Added more explaination in the resctrl.rst
>>      Added checks to detect "Unassigned" before reading RMID.
>>
>> v5: New patch.
>> ---
>>   Documentation/arch/x86/resctrl.rst        | 11 +++++++++++
>>   arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 13 ++++++++++++-
>>   2 files changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/arch/x86/resctrl.rst
>> b/Documentation/arch/x86/resctrl.rst
>> index fe9f10766c4f..aea440ee6107 100644
>> --- a/Documentation/arch/x86/resctrl.rst
>> +++ b/Documentation/arch/x86/resctrl.rst
>> @@ -294,6 +294,17 @@ with the following files:
>>   "num_mbm_cntrs":
>>       The number of monitoring counters available for assignment.
>>   +    Resctrl subsystem provides the interface to count maximum of two
>> +    MBM events per group, from a combination of total and local events.
>> +    Keeping the current interface, users can assign a maximum of two
>> +    monitoring counters per group. User will also have the option to
>> +    enable only one counter to the group.
>> +
>> +    With limited number of counters, system can run out of assignable
>> counters.
>> +    In mbm_cntr_assign mode, the MBM event counters will return
>> "Unassigned" if
>> +    the counter is not assigned to the event when read. Users need to
>> assign a
>> +    counter manually to read the events.
> 
> This seems more appropriate for the "mon_data" section.

Sure. Will do.

-- 
Thanks
Babu Moger