linux-kernel - Re: [PATCH 1/2] x86: Remove dynamic NOP selection

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Message-ID: <20B57BDC-9A3F-4B02-9BA9-41477088A6CE@zytor.com>
Date: Sun, 21 Jan 2024 16:15:57 -0800
From: "H. Peter Anvin" <hpa@...or.com>
To: Thorsten Glaser <tg@...ian.org>
CC: Peter Zijlstra <peterz@...radead.org>, x86@...nel.org, rostedt@...dmis.org,
        torvalds@...uxfoundation.org, linux-kernel@...r.kernel.org,
        linux-toolchains@...r.kernel.org, jpoimboe@...hat.com,
        alexei.starovoitov@...il.com, mhiramat@...nel.org
Subject: Re: [PATCH 1/2] x86: Remove dynamic NOP selection

On January 21, 2024 3:58:11 PM PST, Thorsten Glaser <tg@...ian.org> wrote:
>H. Peter Anvin dixit:
>
>> But yes, with all even remotely recent CPUs all actually handling nopl
>> properly, this isn't relevant anymore.
>
>This was, incidentally, triggered by looking into a problem report that
>something did *not* work on a Geode LX system.
>
>People don’t just run Linux on “recent CPUs” (though I at least got me
>an Atom and a Core2Duo for it and run BSD on my Pentium-M and VIA C7
>systems).
>
>bye,
>//mirabilos

Yes, but it is a matter of where we optimize for performance as opposed to correctness.