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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 72144C35671 for ; Sat, 22 Feb 2020 18:13:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4034D206EF for ; Sat, 22 Feb 2020 18:13:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pDm+h/yZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726828AbgBVSMw (ORCPT ); Sat, 22 Feb 2020 13:12:52 -0500 Received: from mail-oi1-f196.google.com ([209.85.167.196]:44448 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726310AbgBVSMv (ORCPT ); Sat, 22 Feb 2020 13:12:51 -0500 Received: by mail-oi1-f196.google.com with SMTP id d62so5011582oia.11; Sat, 22 Feb 2020 10:12:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=hihCTLsn58SiIEuraoW0VJp1oBOLey3E988oD/herXE=; b=pDm+h/yZOxgNP0sCWlGw+uv0LKtdiOzmQ/JG7uUZFkHm0WDj4PuF8bs10JQlmws8d1 63LFOgPS7PM5+REmNvBwUkurhlkDjKkEpIlgzNVEKZ9uUCrLszkUSnL1Yu+H0qKLe2Ia rn+t7406yPSOSYTKq04Gn95RW3N8awXyxYt2Ja09Q9s5C+C0aOlELc5pltv2PnI4p/tA DjpkwuvYEb8O6b23S894BAuqairHU4Xim11BtmWQKe4cYIivIvHQM8rgo8Bl+xzpRGB0 T095umF98MB+tupWeXqtjL9JU0yJfTJF6udVkfVdT2fSxIBkPyMlkW5YABdUTakqe+ft dCEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=hihCTLsn58SiIEuraoW0VJp1oBOLey3E988oD/herXE=; b=nH+BZNjim8rEKwoafPz+z6BfLO5S/8Y9eMozSj7CTYygDoUhnxmVCemsjEKxhBbIDs S5wyj5YxOUox6zK9SHvPR6JfaUayAM2C0zr0mSAZv1+AydQAAjmCEhpLDWXFtpoXedwB i/ZliHyAObQAMV1DZLmKp2/Z3UQ1NgezkhsfZ4fqh5E10KuzP5uVg3EjNgcSRf/jrior 5p0bwOx24VjKwJ8ttaR1dYjetZdTMc4sKDH44SiCGK/8NWClpZYWDD6ikeab3xWp9p1v ui89nZp18kPwetO7GaLdWCjL2ZF3btVSO3GJmYrD7NFwTMCP0mA18MBLmp6FvVGoK+RV WeJQ== X-Gm-Message-State: APjAAAXkDCwq6+Ui40gYGf3L2SK4gGi0cMzUO2uBKvR28OoS2z9tD9qB hd4VYV7rZH7C3+6cOlymG4c= X-Google-Smtp-Source: APXvYqzJ0Crd1ggjKEJY+mR1yAlXQFP7CMlJSf4HMNFeSEYJb6VLqXC3bgriO6S0rSeeYP19Mqwxpw== X-Received: by 2002:a05:6808:b23:: with SMTP id t3mr7106123oij.88.1582395170927; Sat, 22 Feb 2020 10:12:50 -0800 (PST) Received: from ubuntu-m2-xlarge-x86 ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id 3sm2451668otd.15.2020.02.22.10.12.50 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 22 Feb 2020 10:12:50 -0800 (PST) Date: Sat, 22 Feb 2020 11:12:49 -0700 From: Nathan Chancellor To: "Alex Xu (Hello71)" Cc: Russell King , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, masahiroy@kernel.org, michal.lkml@markovi.net Subject: Re: [PATCH] kbuild: move -pipe to global KBUILD_CFLAGS Message-ID: <20200222181249.GA23843@ubuntu-m2-xlarge-x86> References: <20200222003820.220854-1-alex_y_xu.ref@yahoo.ca> <20200222003820.220854-1-alex_y_xu@yahoo.ca> <20200222021619.GA51223@ubuntu-m2-xlarge-x86> <1582341758.yo66djba3t.none@localhost> <20200222080140.GA40311@ubuntu-m2-xlarge-x86> <1582381271.1karmgahx0.none@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1582381271.1karmgahx0.none@localhost> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 22, 2020 at 09:24:14AM -0500, Alex Xu (Hello71) wrote: > Excerpts from Nathan Chancellor's message of February 22, 2020 3:01 am: > > I used hyperfine [1] to run a quick benchmark with a freshly built > > GCC 9.2.0 for x86 and aarch64 and here are the results: > > > > In both cases it seems like performance regresses (by 1% but still) but > > maybe it is my machine, even though this benchmark was done on a > > different machine than the one from my commit back in 2018. > > > > I am not sure I would write off these results, since I did the benchmark > > 25 times on each one back to back, eliminating most of the variance that > > you described. > > > > [1]: https://github.com/sharkdp/hyperfine > > > > Cheers, > > Nathan > > > > What kernel version are you running? Do you have the 5.6 pipe reworks? No, it is a stock Ubuntu 18.04 kernel, which is running 4.15.0. $ uname -a Linux c2-medium-x86 4.15.0-50-generic #54-Ubuntu SMP Mon May 6 18:46:08 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux If you are curious about the specs: $ neofetch --stdout nathan@c2-medium-x86 -------------------- OS: Ubuntu 18.04.3 LTS x86_64 Host: PowerEdge R6415 Kernel: 4.15.0-50-generic Uptime: 126 days, 12 hours, 39 mins Packages: 686 Shell: zsh 5.4.2 Terminal: /dev/pts/0 CPU: AMD EPYC 7401P 24- (48) @ 2.794GHz Memory: 2974MiB / 64018MiB Cheers, Nathan