From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA03FC4332B for ; Fri, 12 Mar 2021 17:37:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A728B64E68 for ; Fri, 12 Mar 2021 17:37:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232348AbhCLRgx (ORCPT ); Fri, 12 Mar 2021 12:36:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232253AbhCLRgW (ORCPT ); Fri, 12 Mar 2021 12:36:22 -0500 Received: from mail-il1-x132.google.com (mail-il1-x132.google.com [IPv6:2607:f8b0:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CCCBC061574; Fri, 12 Mar 2021 09:36:22 -0800 (PST) Received: by mail-il1-x132.google.com with SMTP id e7so3280144ile.7; Fri, 12 Mar 2021 09:36:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc; bh=dN5wWCL4386GqSoA/EHOirCNKD6L6wdiesXxnENmxI4=; b=uwmdaRLNlcTGrBoHcZg9vpO17c4wP0MIYDnS+c6SUFnK19aH1uc8zwC13NkqAhVN9J lr4JIaMa/r9t8/EnXQ01FAm91BrrxU55AyshFsirtI42pCVGPFf+NPbCWbS1oVHyQPav 88P0GeJGfKWqgbEgNJtETZHBBvQrQfdb5sxGvkUdsWBd5vmGXblcEgI60IxeXBxBSy29 9Dy0GZsOYeZvUEV1Jk72JFljzqE9aPzKYrc/ApY7AxWFyHNt3ZBIuKTNnkaWNPmoRQWO TEA5KJC1nMatvl++btw4dkfb45vH4fGzaGBy8PqlDP1LdgHrDekHCjLyQ+62s01h1xr9 E1rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:reply-to :from:date:message-id:subject:to:cc; bh=dN5wWCL4386GqSoA/EHOirCNKD6L6wdiesXxnENmxI4=; b=IWaf0TbNbKsQGrWeNgt1iIlkfIoxmI75y+UwIEDiBfRqkuKKV60MYHDHGrwYKvI2zd tT3Omh6L2rRzVD8vFymkmcLLGZ/kJ/U0fHSs2j3jg+UryknF1rAOYElsId40bWl+Nlai jNTFK5lmRIZF8jxAKaKfywo/yqAQu1UDIe0rlHNTHZniRAgAAoE4xfODMfKKZJFVVtNl YbvGcYo/B+36Z2HoRCG4X0zVgGuressZ/YXoSxP/gm6VsOizcbtfcEa5avYP29VCmBTk pQ4+AGITFyJHI0PNKJ8zgdetpvV9JqebFIHWoe5WpfB5dz9wey6sAdnLTAnGkmNLKnwH WjCw== X-Gm-Message-State: AOAM533OYoeOSMKnvWGQxiYMDaHbQnzqmibkHdpv4zEfg2JsnX5BjkqT ShdRuNPKyDv43rnWIK8fsEWnRIsmEqUxtEPJ+9M= X-Google-Smtp-Source: ABdhPJwS/i2cdWbmHCySXYUOm3H63v3joSX1rd/sI2Q5oPC4Rhia8d49/en/fQwRV7y/dZ2La6gGcG1FBfZVsE0dH7U= X-Received: by 2002:a92:c7c2:: with SMTP id g2mr3638312ilk.209.1615570581648; Fri, 12 Mar 2021 09:36:21 -0800 (PST) MIME-Version: 1.0 References: <20210312113253.305040674@infradead.org> <20210312144726.GA22098@zn.tnic> <20210312122622.603bd82c@gandalf.local.home> In-Reply-To: <20210312122622.603bd82c@gandalf.local.home> Reply-To: sedat.dilek@gmail.com From: Sedat Dilek Date: Fri, 12 Mar 2021 18:35:45 +0100 Message-ID: Subject: Re: [PATCH 0/2] x86: Remove ideal_nops[] To: Steven Rostedt Cc: Borislav Petkov , Peter Zijlstra , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 12, 2021 at 6:26 PM Steven Rostedt wrote: > > On Fri, 12 Mar 2021 15:47:26 +0100 > Borislav Petkov 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. > Hey Steve, you degraded me to a number :-). I dunno which Git tree this patchset applies to, but I check if I can apply the patchset to my current local Git. Then build a kernel in the same build-environment. Lemme see. To say with Linus's words: "Numbers talk - bullshit walks." - Sedat -