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Date: Tue, 20 Feb 2024 15:23:59 -0600
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Reply-To: babu.moger@amd.com
Subject: Re: [PATCH v2 06/17] x86/resctrl: Introduce interface to display
 number of ABMC counters
Content-Language: en-US
To: James Morse <james.morse@arm.com>, corbet@lwn.net, fenghua.yu@intel.com,
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References: <20231201005720.235639-1-babu.moger@amd.com>
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From: "Moger, Babu" <babu.moger@amd.com>
In-Reply-To: <5ad6f627-45c6-4c2b-b761-c74f0fe85f6c@arm.com>
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Hi James,

On 2/20/24 12:14, James Morse wrote:
> Hi Babu,
> 
> On 19/01/2024 18:22, Babu Moger wrote:
>> The ABMC feature provides an option to the user to pin (or assign) the
>> RMID to the hardware counter and monitor the bandwidth for a longer
>> duration. There are only a limited number of hardware counters.
>>
>> Provide the interface to display the number of ABMC counters supported.
> 
> 
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index a6c336b6de61..fa492ea820f0 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -823,6 +823,10 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
>>  			resctrl_file_fflags_init("mbm_local_bytes_config",
>>  						 RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
>>  		}
>> +
> 
>> +		if (rdt_cpu_has(X86_FEATURE_ABMC))
> 
> Please put this in a header and calling it something like
> resctrl_arch_has_assignable_counters(). These X86 feature definition macros aren't
> available on other architectures!

Sure. Will do.

> 
> 
>> +			resctrl_file_fflags_init("mbm_assignable_counters",
>> +						 RFTYPE_MON_INFO);
>>  	}
>>  
>>  	l3_mon_evt_init(r);
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 3e233251e7ed..53be5cd1c28e 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -811,6 +811,17 @@ static int rdtgroup_rmid_show(struct kernfs_open_file *of,
>>  	return ret;
>>  }
>>  
>> +static int rdtgroup_mbm_assignable_counters_show(struct kernfs_open_file *of,
>> +						 struct seq_file *s, void *v)
>> +{
>> +	struct rdt_resource *r = of->kn->parent->priv;
> 
>> +	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> 
> (After the move out to /fs/ the resctrl_to_arch_res() macro is private to the arch code.
>  Needing to do this when providing a value to user-space is the indication that the value
>  should be in struct rdt_resource instead!)

Ok. Sure. Will

> 
> 
>> +	seq_printf(s, "%d\n", hw_res->mbm_assignable_counters);
>> +
>> +	return 0;
>> +}
>> +
>>  #ifdef CONFIG_PROC_CPU_RESCTRL
>>  
>>  /*
> 
> 
> Thanks,
> 
> James

-- 
Thanks
Babu Moger