linux-kernel - Re: The killing of ideal

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Message-ID: <362BD2A4-016D-4F6B-8974-92C84DC0DDB4@zytor.com>
Date:   Tue, 09 Mar 2021 16:33:45 -0800
From:   hpa@...or.com
To:     Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>
CC:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: The killing of ideal_nops[]

On March 9, 2021 1:24:44 PM PST, Peter Zijlstra <peterz@...radead.org> wrote:
>On Tue, Mar 09, 2021 at 12:05:19PM -0500, Steven Rostedt wrote:
>> On Tue, 9 Mar 2021 17:58:17 +0100
>> Peter Zijlstra <peterz@...radead.org> wrote:
>> 
>> > Hi,
>> > 
>> > AFAICT everything made in the past 10 years ends up using p6_nops.
>Is it
>> > time to kill off ideal_nops[] and simplify life?
>> > 
>> 
>> Well, the one bug that was reported recently was due to a box that
>uses a
>> different "ideal_nops" than p6_nops. Perhaps we should ask him if
>there's
>> any noticeable difference between using p6_nops for every function
>than the
>> ideal_nops that as found for that box.
>
>If the machine is more than a decade old, I'm not really caring about
>optimal performance. If it is 32bit, I really couldn't be arsed as long
>as it boots.

p6_nops don't boot on all 32-bit chips.
-- 
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