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=-7.7 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,MENTIONS_GIT_HOSTING, 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 B196AC433DB for ; Tue, 30 Mar 2021 12:32:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D499619BB for ; Tue, 30 Mar 2021 12:32:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231584AbhC3McT (ORCPT ); Tue, 30 Mar 2021 08:32:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231848AbhC3Mb6 (ORCPT ); Tue, 30 Mar 2021 08:31:58 -0400 Received: from mail-io1-xd35.google.com (mail-io1-xd35.google.com [IPv6:2607:f8b0:4864:20::d35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9090C061574; Tue, 30 Mar 2021 05:31:57 -0700 (PDT) Received: by mail-io1-xd35.google.com with SMTP id n21so16223010ioa.7; Tue, 30 Mar 2021 05:31:57 -0700 (PDT) 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=z9mOZw8SqKLWog9ie4BJd3vxX52rVUoc2ACdWLVcbOs=; b=PegYgqpOFIr0VRpiNtmNwryckYfps61W6ZvFqZhXsfyJGDOUqH3Im0RQ68Jd8/YO9V 5dajLVD4xQFjbB/kvKt96eyKH8PQNQsY1RBwvrnu4kQJEnHQNWJqQq46N3IpMPNyAas4 5fWT/Gg5gJbmLw/0FDuzwQBKOMj4CXQ1QEyewXJ1n6i3zKa8KpXBxgYRBkOSROJcv6Rz NDm2IUTaJ3FQL8j5mmTPrFTBvwKGJJuw/S7vGr9bt1IwPuQbbosWqNhW/ECHZGAPGKvU frCsQvxbA4OOrWq9qAj5ZmdmFjFF4/9Sa4xScmN6df0KHzdCQYiwWHoMXYDPrYa67pNl gidA== 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=z9mOZw8SqKLWog9ie4BJd3vxX52rVUoc2ACdWLVcbOs=; b=bXRW3HRmIZTEySn6yq2/bpfNWG/k+YYnM8S8SidC77wwuKDloDfz07/0H6zFgbwaqi pbi6/HyDlNjlK/wkbz+Yc2LEfuMoYHutavw7MPEBonsXi/gfznzAx65uqI2MZ1HhPBpv +MJ8CEkSzTeQ63LlzlGUT6VjvOdD8G/HQlrB47N0hgk2GS6MeBlGMorgFoA58yG9jLLq BWUsxwqXPT79/o2hgtypOccLRXP6w9fmt29ibS0+jDMkgnfEjGHa0lpY5+aHLweFCVIW NVXJYQsJjLyDOKuN6hsAT3fWFCxYPNha8MmdBJys/LzQ//0CldQU381daiZHzK2Uci4O i+ew== X-Gm-Message-State: AOAM532E9M0HyUs3OzdJ2VmnzqoatHf6lVgYsr2DV2zJc12eZz9yplwk Mh1MeZv/5hwsZ7DSp32q1ytJli76EXNwB25l+Vc= X-Google-Smtp-Source: ABdhPJyzAfqN9KH4XcP/n9EV4Pjo8x8XR3C28vjbEre/kQc1sEOTsXEZkaQQTTzxSwdlsGD8PPxr/5E3wjB4TAri36A= X-Received: by 2002:a05:6638:35ab:: with SMTP id v43mr28883010jal.65.1617107517291; Tue, 30 Mar 2021 05:31:57 -0700 (PDT) MIME-Version: 1.0 References: <20210313121541.GC16144@zn.tnic> <20210313124919.GD16144@zn.tnic> <20210313132927.GF16144@zn.tnic> In-Reply-To: Reply-To: sedat.dilek@gmail.com From: Sedat Dilek Date: Tue, 30 Mar 2021 14:31:30 +0200 Message-ID: Subject: Re: [PATCH 0/2] x86: Remove ideal_nops[] To: Linus Torvalds Cc: Peter Zijlstra , Borislav Petkov , "the arch/x86 maintainers" , Steven Rostedt , Peter Anvin , Linux Kernel Mailing List , linux-toolchains@vger.kernel.org, Josh Poimboeuf , Alexei Starovoitov , Masami Hiramatsu Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Sat, Mar 27, 2021 at 9:02 PM Linus Torvalds wrote: > > On Sat, Mar 27, 2021 at 5:08 AM Sedat Dilek wrote: > > > > debian-5.10.19 as host-kernel: > > 11655.755564957 seconds time elapsed > > > > dileks-5.12-rc3 plus x86-nops as host-kernel: > > 11941.439350080 seconds time elapsed > > That's 2.5% - a huge difference. Particularly since kernel build times > shouldn't even be that kernel-intensive. > > I think there's something else going on than the nops. Same config? > There are likely many other differences between 5.10.19 and 5.12-rc3. > > So can you check just plain 5.12-rc3 and then 5.12-rc3 plus x86-nops, > with otherwise identical configuration? > Hi Linus, I re-checked my linux-config and custom patchset. I had "kbuild: add CONFIG_VMLINUX_MAP expert option" in my queue and build with CONFIG_VMLINUX_MAP=y. This option generated here an approx. 30MiB big vmlinux.map file. Cannot say how long this is taking in seconds but that can explain the the time-diff. [ The above option is helpful to analyze a recent Linux-kernel build with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. Always, I was able to build but not boot on bare metal with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. With a LLVM toolchain, of course. ] ( In the meantime Debian has a 5.20.26 kernel released - so if you want I can re-test with Linux v5.12-rc5. ) Regards, - Sedat - [1] https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/commit/?h=kbuild&id=babd8cd96d333cb83c9b8abf4f01ab1f161d6ec4