linux-kernel - Re: [PATCH V3 2/4] x86/resctrl: Enumerate per-thread MBA

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Message-ID: <e8b35231-f94e-ba25-125d-12819478bb24@intel.com>
Date:   Thu, 14 May 2020 13:12:01 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Babu Moger <babu.moger@....com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "fenghua.yu@...el.com" <fenghua.yu@...el.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "tony.luck@...el.com" <tony.luck@...el.com>
Cc:     "kuo-lang.tseng@...el.com" <kuo-lang.tseng@...el.com>,
        "ravi.v.shankar@...el.com" <ravi.v.shankar@...el.com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 2/4] x86/resctrl: Enumerate per-thread MBA

Hi Babu,

On 5/14/2020 12:04 PM, Babu Moger wrote:
> 
> 
>> -----Original Message-----
>> From: Reinette Chatre <reinette.chatre@...el.com>
>> Sent: Wednesday, May 6, 2020 6:50 PM
>> To: tglx@...utronix.de; fenghua.yu@...el.com; bp@...en8.de;
>> tony.luck@...el.com
>> Cc: kuo-lang.tseng@...el.com; ravi.v.shankar@...el.com; mingo@...hat.com;
>> Moger, Babu <Babu.Moger@....com>; hpa@...or.com; x86@...nel.org;
>> linux-kernel@...r.kernel.org; Reinette Chatre <reinette.chatre@...el.com>
>> Subject: [PATCH V3 2/4] x86/resctrl: Enumerate per-thread MBA
>>
>> From: Fenghua Yu <fenghua.yu@...el.com>
>>

...

>> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
>> index 62b137c3c97a..bccfc9ff3cc1 100644
>> --- a/arch/x86/kernel/cpu/scattered.c
>> +++ b/arch/x86/kernel/cpu/scattered.c
>> @@ -35,6 +35,7 @@ static const struct cpuid_bit cpuid_bits[] = {
>>  	{ X86_FEATURE_CDP_L3,		CPUID_ECX,  2, 0x00000010, 1
>> },
>>  	{ X86_FEATURE_CDP_L2,		CPUID_ECX,  2, 0x00000010, 2
>> },
>>  	{ X86_FEATURE_MBA,		CPUID_EBX,  3, 0x00000010, 0 },
>> +	{ X86_FEATURE_PER_THREAD_MBA,	CPUID_ECX,  0, 0x00000010, 3
>> },
> 
> This is a CPUID feature. You can actually detect this feature without
> checking vendor model in patch @1. This patch looks good to me.
> 

This feature is different from the feature introduced in patch 1.

Reinette