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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 1CB4AC43331 for ; Mon, 30 Mar 2020 02:55:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4B4C206CC for ; Mon, 30 Mar 2020 02:55:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="l1lvLll8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729316AbgC3Czl (ORCPT ); Sun, 29 Mar 2020 22:55:41 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:42308 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728965AbgC3Czl (ORCPT ); Sun, 29 Mar 2020 22:55:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:To: Subject:Sender:Reply-To:Cc:Content-ID:Content-Description; bh=NhjPp0hAekGuC1qMQCQiEBENS7NjExpXR6hbG7ha91E=; b=l1lvLll8MgZ41EmxSijmHg5b/N /F8icc0CCuHzvqbo+GyvQyfk+7lqelwE7fv5PGDungOmB0e/JKJ5kF6k97WGjYs95T6YeWR0cbD8m bVTDvStxXLR/TSgVGIbOPJwGPD2G/BhoROH6vu0FBp5mCWbrrYWjAswhTyfjcGCq2x8ptN80UEL7o qy+idSxaDYmgZkTyyvyTWgszI8SqvJCP15bBU4R4JsJeeEjaclm3U+rveJjCEkppRR/fxhw4Jdu0g mVN1298GVPRBmbmaS+kBxErnhAKlyvbCEhfBj1jDc356vVFDZxZJ7N7UeS1BX6fLISh4X1u7N8Os5 qbkP4hyQ==; Received: from [2601:1c0:6280:3f0:897c:6038:c71d:ecac] by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jIkaS-00066h-On; Mon, 30 Mar 2020 02:55:40 +0000 Subject: Re: why does "mem auto-init: clearing system memory may take some time..." takes about 14 sec under 5.4.17 but only few msec under 5.5.1? To: =?UTF-8?Q?Toralf_F=c3=b6rster?= , Linux Kernel References: From: Randy Dunlap Message-ID: Date: Sun, 29 Mar 2020 19:55:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/1/20 9:52 AM, Toralf Förster wrote: > I do wonder (and I'm surprised) about increased boot speed according to dmesg for thi9s hardend Gentoo Linux system: > Linux mr-fox 5.5.1 #1 SMP Sat Feb 1 18:25:21 CET 2020 x86_64 Intel(R) Xeon(R) CPU E5-1650 v3 @ 3.50GHz GenuineIntel GNU/Linux > > Under 5.4.17 I do have usually 14 sec to wait: > > [ 0.497171] mem auto-init: stack:byref_all, heap alloc:on, heap free:on > [ 0.497171] mem auto-init: clearing system memory may take some time... > [ 0.501549] Calgary: detecting Calgary via BIOS EBDA area > [ 0.501550] Calgary: Unable to locate Rio Grande table in EBDA - bailing! > [ 14.083235] Memory: 131812972K/134101088K available (12291K kernel code, 1400K rwdata, 1912K rodata, 1272K init, 2040K bss, 2288116K reserved, 0K cma-reserved) > [ 14.083342] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=12, Nodes=1 > [ 14.083350] Kernel/User page tables isolation: enabled > [ 14.083403] rcu: Hierarchical RCU implementation. > [ 14.083404] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies. > [ 14.083414] NR_IRQS: 4352, nr_irqs: 928, preallocated irqs: 16 > > but with 5.5.1 there's no wait?: > > [ 0.000000] mem auto-init: stack:byref_all, heap alloc:on, heap free:on > [ 0.000000] mem auto-init: clearing system memory may take some time... > [ 0.000000] Memory: 131812876K/134101088K available (12291K kernel code, 1412K rwdata, 1936K rodata, 1260K init, 2012K bss, 2288212K reserved, 0K cma-reserved) > [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=12, Nodes=1 > [ 0.000000] Kernel/User page tables isolation: enabled > [ 0.000000] rcu: Hierarchical RCU implementation. > [ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies. > [ 0.000000] NR_IRQS: 4352, nr_irqs: 928, preallocated irqs: 16 > [ 0.000000] random: get_random_bytes called from start_kernel+0x4a8/0x659 with crng_init=0 > > Do I miss something? (The kernel config was derived via "make oldconfig"). Hi > Toralf, Curious/odd. Do you have the kernel .config files for 5.4.17 and 5.5.1? Looks like it would have to be a config difference AFAICT. -- ~Randy