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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 BFFF0C432C0 for ; Mon, 18 Nov 2019 02:34:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EACA206D6 for ; Mon, 18 Nov 2019 02:34:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="vRfVZ/9Q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726325AbfKRCet (ORCPT ); Sun, 17 Nov 2019 21:34:49 -0500 Received: from mail-pl1-f182.google.com ([209.85.214.182]:45561 "EHLO mail-pl1-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725905AbfKRCes (ORCPT ); Sun, 17 Nov 2019 21:34:48 -0500 Received: by mail-pl1-f182.google.com with SMTP id w7so8831065plz.12 for ; Sun, 17 Nov 2019 18:34:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=nxeQCTFouT/2s5fT1e6V3nFQ4a6l1Cid4i4aOiaISzE=; b=vRfVZ/9Q0OQ9iYI/uGlws6Bk0WXb0lrIG6WllpGzCR/3YfmPGXJRNX1o1kE+hBsNrS QISpjk9kgyisEOmDFk9huwsluLKfDEmdt2Y/QsDB0AwdU3GhaBK3wvNFYOvs8Ild/GOq WxFkAYV9wvlR79VA/dQqoVZ/V9/vPEI32NUlTwPBfosKNy5PZi453Bz5Yg++TlayasrT D9sExeJD1rC54Ae4QeCUiXRNeJp+EkvyvzuyBFSoEhpAyJE0ufM+Uxw8J03XzvMbx6j6 clST7zS1dA1LYdXOWDb6q4Wc9sPLsacv6eerQDHV8i+eXLCXIkH5AhwC6CNU2/NTVyCo hC2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=nxeQCTFouT/2s5fT1e6V3nFQ4a6l1Cid4i4aOiaISzE=; b=lRPq37YtL8X3eVCv785tGyGDOCt//2CFCLskRXlfQJ6d4m7dk2cc9mP07brGs+gpL+ u1MeJaif9le0Nvvq673dlyd7UR15+bzZpM6Bts+BrVQcfbcu03FKeUkI3Dx7lmCh6Z2k S5dak8CevTC231yvaTdgiXtCxDYJH/78ymyO4vFszOcEleCk7pBPTQaic6v3ErZFlbaQ /MxpEl8KOrJDqEbnSgiDdvSb/nr/LegPB8GoCrjlmgs3jNsXFGwg09b2gfB7cdmU9/9C WLHJ3tqsMCyTrdD/SAToekFdwRcW98nbTqzA+xJ9XW+y08aXhkQWhvHE2lybQqNVQ9Ot Z0bg== X-Gm-Message-State: APjAAAWmTJ2Xv2DWzoBdRkmKN2UmvHUKyaQY30O8s55SnkJ1gj4ctex9 9RavUXGayPe1loTw2phD7iXL8n4k5Wc= X-Google-Smtp-Source: APXvYqzoCcD4MZKcKt/hzJeZ34eSGd4uZVquwZDi1OIa0omZc9KytuAg6FmOthTJrsvred2sJfcdJw== X-Received: by 2002:a17:902:b203:: with SMTP id t3mr22878135plr.51.1574044486212; Sun, 17 Nov 2019 18:34:46 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id e59sm21281508pjk.28.2019.11.17.18.34.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 17 Nov 2019 18:34:45 -0800 (PST) Subject: Re: Recent slowdown in single object builds To: Masahiro Yamada Cc: "linux-kernel@vger.kernel.org" References: <8caa1edf-9c6f-15e4-218d-c266013f8e28@kernel.dk> From: Jens Axboe Message-ID: <38007c4c-45ff-d00e-05c5-948a2df783df@kernel.dk> Date: Sun, 17 Nov 2019 19:34:42 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/17/19 5:40 PM, Masahiro Yamada wrote: > On Sun, Nov 17, 2019 at 1:57 AM Jens Axboe wrote: >> >> On 11/16/19 12:17 AM, Masahiro Yamada wrote: >>> On Sat, Nov 16, 2019 at 8:10 AM Jens Axboe wrote: >>>> >>>> Hi, >>>> >>>> I've noticed that current -git is a lot slower at doing single object >>>> builds than earlier kernels. Here's an example, building the exact same >>>> file on 5.2 and -git: >>>> >>>> $ time make fs/io_uring.o >>>> real 0m5.953s >>>> user 0m5.402s >>>> sys 0m0.649s >>>> >>>> vs 5.2 based (with all the backports, identical file): >>>> >>>> $ time make fs/io_uring.o >>>> real 0m3.218s >>>> user 0m2.968s >>>> sys 0m0.520s >>>> >>>> Any idea what's going on here? It's almost twice as slow, which is >>>> problematic... > > > BTW, I am using a cheap machine based on Intel Core i7-6700K. > I can build fs/io_uring.o (based on x86_64_defconfig) much faster. > > > The slowdown (1.990 sec -> 2.861 sec) is not terrible for me. For those of us that do single object builds all the time the slowdown is pretty damn terrible. Granted that your 44% slowdown isn't as bad as my 85% slowdown, but it's still a MASSIVE slowdown. -- Jens Axboe