linux-kernel - Re: [PATCH 2/6] x86: bug: prevent gcc distortions

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Message-ID: <20180518155359.GF17285@pd.tnic>
Date:   Fri, 18 May 2018 17:53:59 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Nadav Amit <namit@...are.com>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Denys Vlasenko <dvlasenk@...hat.com>
Subject: Re: [PATCH 2/6] x86: bug: prevent gcc distortions

On Fri, May 18, 2018 at 03:46:33PM +0000, Nadav Amit wrote:
> In case you didn’t read the cover-letter: the patch-set does give a 2%
> performance improvement for #PF-MADV_DONTNEED microbenchmark loop.

I saw it but *micro*-benchmark doesn't tell me a whole lot. If that
"improvement" is not visible in real workloads/benchmarks, then I'm just
as unimpressed.

-- 
Regards/Gruss,
    Boris.

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