From: Borislav Petkov <[email protected]>
To: Ammar Faizi <[email protected]>
Cc: Andy Shevchenko <[email protected]>,
Dave Hansen <[email protected]>,
"H. Peter Anvin" <[email protected]>, Ingo Molnar <[email protected]>,
Josh Poimboeuf <[email protected]>,
Juergen Gross <[email protected]>,
Kees Cook <[email protected]>,
Peter Zijlstra <[email protected]>,
Thomas Gleixner <[email protected]>,
Tony Luck <[email protected]>,
Youquan Song <[email protected]>,
[email protected], [email protected],
[email protected], [email protected]
Subject: Re: [PATCH v1 0/2] x86: Avoid using INC and DEC instructions on hot paths
Date: Mon, 7 Mar 2022 13:38:59 +0100 [thread overview]
Message-ID: <YiX81kD/[email protected]> (raw)
In-Reply-To: <[email protected]>
On Mon, Mar 07, 2022 at 06:45:56PM +0700, Ammar Faizi wrote:
> In order to take maximum advantage of out-of-order execution,
> avoid using INC/DEC instructions when appropriate. INC/DEC only
> writes to part of the flags register, which can cause a partial
> flag register stall. This series replaces INC/DEC with ADD/SUB.
"Improvements" like that need to show in benchmark runs - not
microbenchmark - that they bring anything. Just by looking at them, I'd
say they won't show any difference. But I'm always open to surprises.
Btw, you don't have to send all your patches directly to me - there are
other x86 maintainers. IOW, you can use scripts/get_maintainer.pl to
figure out who to send them to.
Also, I'd advise going over Documentation/process/ if you're new to this.
Especially Documentation/process/submitting-patches.rst.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-03-07 12:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 11:45 [PATCH v1 0/2] x86: Avoid using INC and DEC instructions on hot paths Ammar Faizi
2022-03-07 11:45 ` [PATCH v1 1/2] x86/include/asm: " Ammar Faizi
2022-03-07 11:45 ` [PATCH v1 2/2] x86/lib: " Ammar Faizi
2022-03-07 12:38 ` Borislav Petkov [this message]
2022-03-07 13:37 ` [PATCH v1 0/2] x86: " Ammar Faizi
2022-03-09 9:33 ` Borislav Petkov
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