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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY,USER_AGENT_NEOMUTT 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 819F4C43142 for ; Tue, 26 Jun 2018 11:28:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33338269CB for ; Tue, 26 Jun 2018 11:28:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ikMPNtkK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33338269CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934672AbeFZL2S (ORCPT ); Tue, 26 Jun 2018 07:28:18 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:34480 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934276AbeFZL2N (ORCPT ); Tue, 26 Jun 2018 07:28:13 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w5QBO080040475; Tue, 26 Jun 2018 11:27:15 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2017-10-26; bh=dy9THHLyv2DDW000Xhe0GuH1RZXO63QpIAr1lF7KC9M=; b=ikMPNtkKO5JKS6tVnP+3VbG+sgCa56N39cX0j30olkyG9qnbgJpB0xpJkJcmvWqPEHk4 3qpcZXqOLAbD7vbrt+vaxg3j/URKm0htsnoESeVRdF7SXuyPkRyecG1NsicMKWGFe3pw eSO+/3EhO6AlBcFQ4OabsEMiDyD9aprrw4J7+TuFsUmqIBe+hJs2OgYM8B97t3JC1zyq dS2TBIHii2un/efJjbO/TXQ/i6y2Ca5LCF0hPS5ZmJHy6l8fYKiUMQ5IxDkpZYRlq2+E 6g9lbOv2eBhXnvX9+FvhiVQIqtNWjwKU0e77pb/ESHkoy77xn9+t62fYPhQxkAt1mNO+ UA== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2130.oracle.com with ESMTP id 2jum57r30f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 26 Jun 2018 11:27:14 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w5QBRCQV027198 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 26 Jun 2018 11:27:12 GMT Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w5QBRAHS024359; Tue, 26 Jun 2018 11:27:10 GMT Received: from xakep.localdomain (/73.69.118.222) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 26 Jun 2018 04:27:08 -0700 Date: Tue, 26 Jun 2018 07:27:05 -0400 From: Pavel Tatashin To: Peter Zijlstra Cc: steven.sistare@oracle.com, daniel.m.jordan@oracle.com, linux@armlinux.org.uk, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, john.stultz@linaro.org, sboyd@codeaurora.org, x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, douly.fnst@cn.fujitsu.com, prarit@redhat.com, feng.tang@intel.com, pmladek@suse.com, gnomes@lxorguk.ukuu.org.uk, linux-s390@vger.kernel.org Subject: Re: [PATCH v12 10/11] sched: early boot clock Message-ID: <20180626112705.4dxrsd5acvobla5y@xakep.localdomain> References: <20180621212518.19914-1-pasha.tatashin@oracle.com> <20180621212518.19914-11-pasha.tatashin@oracle.com> <20180625085543.GT2494@hirez.programming.kicks-ass.net> <20180625192320.kzmqkvmfh5aeuhhx@xakep.localdomain> <20180626090003.GA2458@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180626090003.GA2458@hirez.programming.kicks-ass.net> User-Agent: NeoMutt/20180622 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8935 signatures=668703 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=676 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1806260129 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > How's something like this? That moves sched_clock_init() to right before > we enable IRQs for the first time (which is after we've started the > whole timekeeping business). > > The thing is, sched_clock_init_late() reall is far too late, we need to > switch to unstable before we bring up SMP. OK, sure. > - sched_clock_postinit(); > + sched_clock_init(); Yes, we can move sched_clock_init(). But placing it after time_init() would work on all arches with unstable clock except for x86. See comment above time_init x86: arch/x86/kernel/time.c 99/* 100 * Initialize TSC and delay the periodic timer init to 101 * late x86_late_time_init() so ioremap works. 102 */ 103void __init time_init(void) 104{ 105 late_time_init = x86_late_time_init; 106} Only After this: > > late_time_init() > > x86_late_time_init() > > x86_init.timers.timer_init() > > hpet_time_init() Only after this call we finally start > > getting clock interrupts, and can get precise output from > > sched_clock_local(). We start getting timer interrupts. Is it acceptable to move sched_clock_init() after late_time_init()? Thank you, Pavel