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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9416C4321E for ; Thu, 1 Dec 2022 21:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231176AbiLAVpQ (ORCPT ); Thu, 1 Dec 2022 16:45:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231166AbiLAVpL (ORCPT ); Thu, 1 Dec 2022 16:45:11 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B110CC673 for ; Thu, 1 Dec 2022 13:45:09 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id f9so2791385pgf.7 for ; Thu, 01 Dec 2022 13:45:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=Wn46VnyUMqzSzQ1K8Ll32Y84XAVx4QsLdJfs9pzff2s=; b=njUgiMv1w3eaALeRfGiRAfEogZF0XpkTXtaI/JcN69XbIgDREebzyGcYDeeyfwqxwr didsmGudQD3e+ffzRjUxzTg0RB/NaIq+WwaQnOzIs69/aA5I65o/69bn+G74NEoMYEzK rcvYS9N5m3ZpuBRmTGVvOmCM+8kBxy1TVHi0/oTQPQ7ClwDJ2zQqaosuOS8wRZheQoVy 8B3zR+DhH9XLVcAZgqkYQ12xJUmNyWmIxg/eJF9Rd9IcD5qCZ0ZZQQmRLa8AI/ohGTNb xRNeSMSfRgawDoRhyOOQsOQBoWyvjw0RysTu0cy63T4RcGgfIgTgTh1rnnGuVIVA+/N4 dawA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Wn46VnyUMqzSzQ1K8Ll32Y84XAVx4QsLdJfs9pzff2s=; b=HnG1L1UYBlQjO5ilGc6Cxr1+Af2CrSjJc+gQrJjc/7u4ypScvPll1C3lnVF1o2Grqc k6DavC7R4cuHBI/Uqfim2sA4qh09UEh2ghosJwaO21VS2AQ5ypVgqhCPRNxBuP+6GXax QT2QsG4XaORrqVkTXABYdArG1myRFbwxOlpWdBoXsGvZx/fm0iyCQwMxGmfE37It0rGd CVeuCYyRiFqHr037KCV0s2g+1Zni5oKEh255wgGbq3FQu85u0EilvDPhIWwRV6ecSFr5 Y3OKXTPVuz8mqa7f39oc07os8qqQLAOramxv24iVtMWYZbuuyNf8a6y0oNoD4r1+XfQL 4fzA== X-Gm-Message-State: ANoB5pksE1l10rxOvDJDGbPfsdojdLda2rcvWqRlrZSpyE8XkeLkEruE LYUUsJDesVcEM7TQNhvQ9MO3w+V+XI2BAN6vkNM26B1v X-Google-Smtp-Source: AA0mqf74OiiJr1/ycuLqcR+MfCt64pJ0eYbzKhTwzKvBv+KcYVP+Nx073aJ9jnZY2v9EFdMFV2Foy0VoL1MwA8A1S3U= X-Received: by 2002:aa7:8753:0:b0:576:4673:ce3e with SMTP id g19-20020aa78753000000b005764673ce3emr2005323pfo.39.1669931108703; Thu, 01 Dec 2022 13:45:08 -0800 (PST) MIME-Version: 1.0 References: <202210181535.7144dd15-yujie.liu@intel.com> <87edv4r2ip.fsf@yhuang6-desk2.ccr.corp.intel.com> <871qr3nkw2.fsf@yhuang6-desk2.ccr.corp.intel.com> <366045a27a96e01d0526d63fd78d4f3c5d1f530b.camel@surriel.com> <07adee081a70c2b4b44d9bf93a0ad3142e091086.camel@surriel.com> <20221201132237.c55c4bd07ba44463b146882e@linux-foundation.org> In-Reply-To: <20221201132237.c55c4bd07ba44463b146882e@linux-foundation.org> From: Yang Shi Date: Thu, 1 Dec 2022 13:44:57 -0800 Message-ID: Subject: Re: [mm] f35b5d7d67: will-it-scale.per_process_ops -95.5% regression To: Andrew Morton Cc: Rik van Riel , Thorsten Leemhuis , "Huang, Ying" , kernel test robot , lkp@lists.01.org, lkp@intel.com, Matthew Wilcox , linux-kernel@vger.kernel.org, linux-mm@kvack.org, feng.tang@intel.com, zhengjun.xing@linux.intel.com, fengwei.yin@intel.com, Nathan Chancellor Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 1, 2022 at 1:22 PM Andrew Morton wrote: > > On Thu, 01 Dec 2022 15:29:41 -0500 Rik van Riel wrote: > > > On Thu, 2022-12-01 at 19:33 +0100, Thorsten Leemhuis wrote: > > > Hi, this is your Linux kernel regression tracker. > > > > > > On 28.11.22 07:40, Nathan Chancellor wrote: > > > > Hi Rik, > > > > > > I wonder what we should do about below performance regression. Is > > > reverting the culprit now and reapplying it later together with a fix > > > a > > > viable option? Or was anything done/is anybody doing something > > > already > > > to address the problem and I just missed it? > > > > The changeset in question speeds up kernel compiles with > > GCC, as well as the runtime speed of other programs, due > > to being able to use THPs more. However, it slows down kernel > > compiles with clang, due to ... something clang does. > > > > I have not figured out what that something is yet. > > > > I don't know if I have the wrong version of clang here, > > but I have not seen any smoking gun at all when tracing > > clang system calls. I see predominantly small mmap and > > unmap calls, and nothing that even triggers 2MB alignment. > > 2.8% speedup for gcc is nice. Massive slowdown in the malloc banchmark > and in LLVM/clang is very bad - we don't know what other userspace will > be so affected. > > So I think we revert until this is fully understood. +1 > >