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From: "H. Peter Anvin" <hpa@zytor.com>
To: Steven Rostedt <rostedt@goodmis.org>
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 18:31:53 -0800	[thread overview]
Message-ID: <50F640B7-AB54-4571-9988-EAD5FD5933A4@zytor.com> (raw)
In-Reply-To: <20240121212236.02331f4c@rorschach.local.home>

On January 21, 2024 6:22:36 PM PST, Steven Rostedt <rostedt@goodmis.org> wrote:
>On Sun, 21 Jan 2024 18:15:39 -0800
>"H. Peter Anvin" <hpa@zytor.com> wrote:
>
>> On 1/21/24 16:56, Steven Rostedt wrote:
>> >>
>> >> 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.
>> >   
>> 
>> There absolutely is such a thing as "optimize for correctness." It means 
>> to keep the code clean, easily testable, and with a minimal number of 
>> distinct code paths so that regressions and *especially* uncaught 
>> regressions get caught quickly.
>
>I call that maintainability, not correctness. It is either correct and
>works, or is incorrect and does not work.
>
>You can change code to be more maintainable and still make it incorrect.
>
>-- Steve

Yes, of course. That's called failure :)

  reply	other threads:[~2024-01-22  2:32 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
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 [this message]
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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