linux-kernel - Re: [PATCH v11 14/23] x86/resctrl: Implement resctrl_arch_config

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Message-ID: <e7d7cd3f-47d1-470d-aa08-49f36682a55a@amd.com>
Date: Fri, 21 Feb 2025 16:24:54 -0600
From: "Moger, Babu" <bmoger@....com>
To: James Morse <james.morse@....com>, Babu Moger <babu.moger@....com>,
 corbet@....net, reinette.chatre@...el.com, tglx@...utronix.de,
 mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
 tony.luck@...el.com, peternewman@...gle.com
Cc: fenghua.yu@...el.com, x86@...nel.org, hpa@...or.com, paulmck@...nel.org,
 akpm@...ux-foundation.org, thuth@...hat.com, rostedt@...dmis.org,
 xiongwei.song@...driver.com, pawan.kumar.gupta@...ux.intel.com,
 daniel.sneddon@...ux.intel.com, jpoimboe@...nel.org, perry.yuan@....com,
 sandipan.das@....com, kai.huang@...el.com, xiaoyao.li@...el.com,
 seanjc@...gle.com, xin3.li@...el.com, andrew.cooper3@...rix.com,
 ebiggers@...gle.com, mario.limonciello@....com, tan.shaopeng@...itsu.com,
 linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
 maciej.wieczor-retman@...el.com, eranian@...gle.com
Subject: Re: [PATCH v11 14/23] x86/resctrl: Implement
 resctrl_arch_config_cntr() to assign a counter with ABMC

Hi James,


On 2/21/2025 12:06 PM, James Morse wrote:
> Hi Babu,
> 
> On 22/01/2025 20:20, 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 it
>> is assigned. The assigned RMID will be tracked by the hardware until the
>> user unassigns it manually.
>>
>> Implement an architecture-specific handler to assign and unassign the
>> counter. Configure counters by writing to the L3_QOS_ABMC_CFG MSR,
>> specifying the counter ID, bandwidth source (RMID), and event
>> configuration.
>>
>> The feature details are documented in the APM listed below [1].
>> [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
>>      Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth
>>      Monitoring (ABMC).
> 
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index acac7972cea4..161d3feb567c 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -724,4 +724,7 @@ unsigned int mon_event_config_index_get(u32 evtid);
>>   void resctrl_arch_mon_event_config_set(void *info);
>>   u32 resctrl_arch_mon_event_config_get(struct rdt_mon_domain *d,
>>   				      enum resctrl_event_id eventid);
>> +int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
>> +			     enum resctrl_event_id evtid, u32 rmid, u32 closid,
>> +			     u32 cntr_id, bool assign);
>>   #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
> 
> 
> Could this be added to include/linux/resctrl.h instead? Its where it needs to end up
> eventually.
> 

As Reinette already mentioned in  [1], Boris wanted this moved when 
arch/fs code separation integrated. Lets keep it in resctrl/internal.h 
for now.

[1] 
https://lore.kernel.org/lkml/e524c376-9ef8-488e-8053-b49ccafd306d@intel.com/ 


Thanks
Babu

> Thanks,
> 
> James
>