Received: by 2002:ac0:a5a7:0:0:0:0:0 with SMTP id m36-v6csp1884741imm; Thu, 19 Jul 2018 09:21:50 -0700 (PDT) X-Google-Smtp-Source: AAOMgpej4SOp/eFzOoKrTu2V7B8cWdzm8a4ySUIpcOGpnZ5EBc204+XRSVHk/5wg4hxIpb5aSSCe X-Received: by 2002:a62:fb05:: with SMTP id x5-v6mr10273571pfm.210.1532017310025; Thu, 19 Jul 2018 09:21:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1532017309; cv=none; d=google.com; s=arc-20160816; b=jgYHs5RZwZm08y0v4xVjJyVfmMHPfsSGeVvFpv1/jZ28z6RCrtCE3ZI0XkbnksP+3A 9hq9hreLbnKjKGI9jyfBpwjAtKerAOZZfHfEg0jYLqHHJY8Ck4GNMZ53NLpOyJV2VR1C gzccwIafLholW2PtRnVvjsuXH52GS+Bbcw4zGNRgtvuSjq2XBhLYT5hbMMLluxtTZqwT sQqJccv5UediDyAO/go4wzLYtyYl2zJIVHn2ajdRtR7ReOfg6vUw0OchJX90oJth5YcI 3CxyY+SJz/s0laWMHEjM2klmQIjCLzEqvvVZ8/g2KjoIFOT6p2BnkgXTgW9xqFCFY87p kLKw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:user-agent:references :message-id:in-reply-to:subject:cc:to:from:date :arc-authentication-results; bh=fvjgaDxjryfeBbLHo3/XJBzPc0noCO4KDiFzvJPQJik=; b=Ble9AyVkg5EvKpetJSx2Yv57Z0I4h+H0ldufqTJt0O9mrpDZ1dYwfy+UvDbO9rCAAY S/ujlp6IELJESTUEefnToiLrhPESFvVLpMXNtZfQ9J8FD+gSX5npz+XdvgJLoMwiRfI4 NRofQ5myIbtLCxWsx5Ttrc9w3NKfffaS7o1kmTX2ZVlTZgJ/nrlULtZLGRP97fA6dY1X y6bcHKAE8FDYorZko3GMwTw41ZNudPitnlD/AqLXhQ0IEylUdwQ/g5/snFtNMjg+/j8c dKCzsFfRfg4REMfRAC/nMsMSxUJMccIOGL5B+DdWW04jxg/BlYJSZ1zjsEefGX0pmlAw hxcA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p4-v6si6298804pgp.299.2018.07.19.09.21.35; Thu, 19 Jul 2018 09:21:49 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732087AbeGSREQ (ORCPT + 99 others); Thu, 19 Jul 2018 13:04:16 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:33623 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731888AbeGSREQ (ORCPT ); Thu, 19 Jul 2018 13:04:16 -0400 Received: from p4fea5a5a.dip0.t-ipconnect.de ([79.234.90.90] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fgBeQ-00032V-2N; Thu, 19 Jul 2018 18:19:34 +0200 Date: Thu, 19 Jul 2018 18:19:33 +0200 (CEST) From: Thomas Gleixner To: Pavel Tatashin cc: Peter Zijlstra , 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, 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, boris.ostrovsky@oracle.com, jgross@suse.com, pbonzini@redhat.com Subject: Re: [PATCH v14 20/25] x86/tsc: calibrate tsc only once In-Reply-To: <4295075b-8a0f-1723-2e80-1bbd2f038846@oracle.com> Message-ID: References: <20180718022211.6259-1-pasha.tatashin@oracle.com> <20180718022211.6259-21-pasha.tatashin@oracle.com> <20180719103340.GA2494@hirez.programming.kicks-ass.net> <4295075b-8a0f-1723-2e80-1bbd2f038846@oracle.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Jul 2018, Pavel Tatashin wrote: > On 07/19/2018 07:01 AM, Thomas Gleixner wrote: > > And hpet_pmtime_calibrate_cpu() contains all the hpet/pmtime stuff. > > However, when cpu_khz = x86_platform.calibrate_cpu() is called the first > time, we still call hpet_pmtime_calibrate_cpu() from > native_calibrate_cpu(). We cannot simply split native_calibrate_cpu() > into two independent functions because it is also called from > recalibrate_cpu_khz(). > So, the question is how to enforce that the first time we do not call hpet/pmtime? > > 1. Use a new global variable? Kind of ugly. > 2. Use system_state == SYSTEM_BOOTING ? Ugly, and probably not very safe. Both are horrible. So create two functions. native_...early..() and native....(). The early one does not contain the hpet/pmtimer stuff and it replaces the ops.pointer with the late one which contains all of it. Hmm? Thanks, tglx