linux-kernel - Re: [PATCH v5] x86/resctrl: Add event choices for mba

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Message-ID: <52df445f-c2cf-44da-aa6b-995a6beeffc6@intel.com>
Date:   Mon, 4 Dec 2023 14:51:55 -0800
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Tony Luck <tony.luck@...el.com>
CC:     "babu.moger@....com" <babu.moger@....com>,
        "Yu, Fenghua" <fenghua.yu@...el.com>,
        Peter Newman <peternewman@...gle.com>,
        "Jonathan Corbet" <corbet@....net>,
        Shuah Khan <skhan@...uxfoundation.org>,
        "x86@...nel.org" <x86@...nel.org>,
        Shaopeng Tan <tan.shaopeng@...itsu.com>,
        James Morse <james.morse@....com>,
        Jamie Iles <quic_jiles@...cinc.com>,
        "Randy Dunlap" <rdunlap@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        "patches@...ts.linux.dev" <patches@...ts.linux.dev>
Subject: Re: [PATCH v5] x86/resctrl: Add event choices for mba_MBps



On 12/4/2023 2:15 PM, Reinette Chatre wrote:
> On 12/4/2023 1:08 PM, Tony Luck wrote:

>>
>> B) "mba_MBps={local|total)" forces use of chosen event, fails if event
>> is unavailable.
> 
> I assume you mean "mba_MBps_event={local|total}". This is my preference but
> I would like to learn more about Babu's "overkill" argument. I do believe that
> (B) is well motivated in [1] and has no impact on AMD.
> My uncertainty here (considering one motivation is to future proof it against
> adding more events) is the generic "local" and "total" names. Even so, all
> I could come up with are "local_bw" and "total_bw", which I do not think are
> improvements.

Thinking about this more the existing names in resctrl may help here
... "mbm_total_bytes" and "mbm_local_bytes"? Any new event would need to
integrate with these names.

Reinette