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From: Steven Rostedt <rostedt@goodmis.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thorsten Glaser <tg@debian.org>,
	Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org, torvalds@linuxfoundation.org,
	linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org,
	jpoimboe@redhat.com, alexei.starovoitov@gmail.com,
	mhiramat@kernel.org
Subject: Re: [PATCH 1/2] x86: Remove dynamic NOP selection
Date: Sun, 21 Jan 2024 19:56:49 -0500	[thread overview]
Message-ID: <20240121195649.7355e1d5@rorschach.local.home> (raw)
In-Reply-To: <20B57BDC-9A3F-4B02-9BA9-41477088A6CE@zytor.com>

On Sun, 21 Jan 2024 16:15:57 -0800
"H. Peter Anvin" <hpa@zytor.com> wrote:

> On January 21, 2024 3:58:11 PM PST, Thorsten Glaser <tg@debian.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.

What problem happened?

> >
> >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.

There is no such thing as "optimize for correctness", it is either
correct or it is not. Correctness should always come before performance
(at least that is what Thomas has pounded into me ;-)

If a kernel use to work on a machine but a newer version no longer
works, I call that a regression.

-- Steve

  reply	other threads:[~2024-01-22  0:56 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-12 11:32 [PATCH 0/2] x86: Remove ideal_nops[] Peter Zijlstra
2021-03-12 11:32 ` [PATCH 1/2] x86: Remove dynamic NOP selection Peter Zijlstra
2021-03-12 12:09   ` Peter Zijlstra
2021-03-12 20:36     ` Linus Torvalds
2024-01-20  6:58   ` Thorsten Glaser
2024-01-20  8:22     ` H. Peter Anvin
2024-01-20 16:53       ` Thorsten Glaser
2024-01-21 23:21         ` H. Peter Anvin
2024-01-21 23:58           ` Thorsten Glaser
2024-01-22  0:15             ` H. Peter Anvin
2024-01-22  0:56               ` Steven Rostedt [this message]
2024-01-22  1:17                 ` Thorsten Glaser
2024-01-22  2:04                   ` H. Peter Anvin
2024-01-22  2:15                 ` H. Peter Anvin
2024-01-22  2:22                   ` Steven Rostedt
2024-01-22  2:31                     ` H. Peter Anvin
2024-01-20 17:00       ` Linus Torvalds
2024-01-20 17:19         ` Thorsten Glaser
2024-01-20 18:21           ` disassemblers (was Re: [PATCH 1/2] x86: Remove dynamic NOP selection) Thorsten Glaser
2024-01-21 22:36         ` [PATCH 1/2] x86: Remove dynamic NOP selection David Laight
2024-01-21 23:10           ` H. Peter Anvin
2021-03-12 11:32 ` [PATCH 2/2] objtool,x86: Use asm/nops.h Peter Zijlstra
2021-03-12 14:29 ` [PATCH 0/2] x86: Remove ideal_nops[] Sedat Dilek
2021-03-12 14:47   ` Borislav Petkov
2021-03-12 17:26     ` Steven Rostedt
2021-03-12 17:35       ` Sedat Dilek
2021-03-12 17:46         ` Borislav Petkov
2021-03-12 17:47         ` Steven Rostedt
2021-03-12 18:13           ` Sedat Dilek
2021-03-12 19:03             ` Sedat Dilek
2021-03-12 20:59 ` Borislav Petkov
     [not found]   ` <CA+icZUWSCS6vAQOXoG6nsW+Dbnogivzf+rmegCTMjz5hjE5cKQ@mail.gmail.com>
2021-03-13  8:49     ` Borislav Petkov
2021-03-13 11:23       ` Borislav Petkov
2021-03-13 12:10       ` Sedat Dilek
2021-03-13 12:15         ` Borislav Petkov
2021-03-13 12:38           ` Sedat Dilek
2021-03-13 12:49             ` Borislav Petkov
2021-03-13 12:58               ` Sedat Dilek
2021-03-13 13:29                 ` Borislav Petkov
2021-03-13 13:47                   ` Sedat Dilek
2021-03-15 17:04                     ` Sedat Dilek
2021-03-15 17:15                       ` Borislav Petkov
2021-03-15 17:19                         ` Sedat Dilek
2021-03-15 17:23                           ` Borislav Petkov
2021-03-15 18:10                       ` Peter Zijlstra
2021-03-15 18:23                         ` Sedat Dilek
2021-03-15 22:14                           ` Peter Zijlstra
2021-03-16  5:56                             ` Sedat Dilek
2021-03-27 12:08                               ` Sedat Dilek
2021-03-27 20:02                                 ` Linus Torvalds
2021-03-30 12:31                                   ` Sedat Dilek

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