linux-kernel - Re: [PATCH V1 01/13] selftests/resctrl: Fix feature detection

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Message-ID: <b83ba95d-9f0f-4d4f-b68c-c5a612afece4@intel.com>
Date:   Wed, 11 Mar 2020 11:06:33 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@...el.com>,
        "shuah@...nel.org" <shuah@...nel.org>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>
Cc:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>, "Luck, Tony" <tony.luck@...el.com>,
        "babu.moger@....com" <babu.moger@....com>,
        "james.morse@....com" <james.morse@....com>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        "Yu, Fenghua" <fenghua.yu@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V1 01/13] selftests/resctrl: Fix feature detection

Hi Sai,

On 3/9/2020 3:51 PM, Prakhya, Sai Praneeth wrote:
>> -----Original Message-----
>> From: Reinette Chatre <reinette.chatre@...el.com>
>> Sent: Monday, March 9, 2020 3:34 PM
> 
> [SNIP]
> 
>>> That's a good point and makes sense to me. I think we could fix it in
>>> two ways 1. grep for strings in dmesg but that will still leave
>>> ambiguity in deciding b/w mbm and cqm because kernel prints "resctrl: L3
>> monitoring detected" for both the features 2. Check in "info" directory
>>> 	a. For cat_l3, we could search for info/L3
>>> 	b. For mba, we could search for info/MB
>>> 	c. For cqm and mbm, we could search for specified string in
>>> info/L3_MON/mon_features
>>>
>>> I think option 2 might be better because it can handle all cases, please let me
>> know what you think.
>>
>> I agree. For the reasons you mention and also that (1) may not be possible if the
>> loglevel prevents those lines from being printed.
> 
> Makes sense. I will work on the fix.

One more note about this ... from what I can tell the test for a feature
currently fails if the platform does not support the feature. Would it
be possible to just skip the test in this case instead?

Reinette