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From: Steven Rostedt <rostedt@goodmis.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Sedat Dilek <sedat.dilek@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org, hpa@zytor.com, 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 0/2] x86: Remove ideal_nops[]
Date: Fri, 12 Mar 2021 12:26:22 -0500	[thread overview]
Message-ID: <20210312122622.603bd82c@gandalf.local.home> (raw)
In-Reply-To: <20210312144726.GA22098@zn.tnic>

On Fri, 12 Mar 2021 15:47:26 +0100
Borislav Petkov <bp@alien8.de> wrote:

> On Fri, Mar 12, 2021 at 03:29:48PM +0100, Sedat Dilek wrote:
> > What does this change exactly mean to/for me?  
> 
> Probably nothing.
> 
> I would be very surprised if it would be at all noticeable for you -
> it's not like the kernel is executing long streams of NOPs in fast
> paths.
> 

With ftrace enabled, every function starts with a NOP. But that said, the
simple answer is for Sedat to apply the patches on his box and do some
performance testing. It doesn't matter if you are white, black, male,
female, or anything in between. As my daughter's swim coach said; it's the
numbers that matter here. Run a bunch of benchmarks on your box on the
latest kernel, apply Peter's patches, and then run the benchmarks again on
the latest kernel with Peter's patches and then report the difference. If
it's negligible then there's nothing to worry about.

-- Steve

  reply	other threads:[~2021-03-12 17:27 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
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 [this message]
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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