Received: by 2002:ac0:a581:0:0:0:0:0 with SMTP id m1-v6csp568788imm; Fri, 29 Jun 2018 02:44:36 -0700 (PDT) X-Google-Smtp-Source: ADUXVKJgo4UGLLLp20RnP3pL23aIPrXAf+jSZbUp86yDneN+ZiT6EttqmPZbizpLURhP+FqAEaVB X-Received: by 2002:a63:3c4a:: with SMTP id i10-v6mr11845098pgn.415.1530265476780; Fri, 29 Jun 2018 02:44:36 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1530265476; cv=none; d=google.com; s=arc-20160816; b=n8Y2jcIiSM4a1jeIPHLxWbGvjTayrdQD4uxXIMtWoOhHPbKQB/m9L//VgoMlU9K8ZN +fKic7B/cITgzHHCqZZkFoyxjTRYvYf6h/G1CwJgsfysNm+AAyjWAfrPiN2hYEkOKbIa lC7VhS94XRhyno8Xz/tHHkAmvxeJ7GFT1V0cmqTFGmZUIdYUDMr8WgxWNNPB29/cRgQI 1hcpDdpIIMDCZD5SDbV+NkemP7WaRATg67Ns7dVki3jxRL3PlW7wNAhkBtz7QhhuZOCw +urhMHf4ZnivzvAM1ajpIqHVPC51JQrLgElw5UdYpsXeifNGD5W5oDFRxkd4XVuMS9wB 734Q== 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=EyYk/VQQsDaK/+RwUre//SSnACW0MtsBKcFUorMPqhs=; b=PLYr9BOEEnVdaxp+1aSKxCuZsVRSwefN7X/qiq/csFgSgQneztZBtmIvC+gPXYkc61 TFRt+5EoA2iEna/K9ijQ5oQzDHCpT1ycd0r8cubV5nMCuknYSMTz8o9eVjxeF+pTeVP/ A4CmtaPjftfHwFQGfU1LzGKOc+p6KKnhVz/PQRAJVlygVn6fjh5q2Zgr61aaOROGY7Pj Wydm+X5fNWU3wGsxTMT647pEukDLK3eWoD9ji5bRSxTzytXYraX3YErcgo6Vp5fa0T+0 BY218M8XX6QeqjQakNv7MDxlu5Tf+oP+4+SvbVc9l/AxfYEzQlnXiEC1jnSe+0XL2amh YPcw== 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 b5-v6si3576799pfo.54.2018.06.29.02.44.22; Fri, 29 Jun 2018 02:44:36 -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 S933142AbeF2Hau (ORCPT + 99 others); Fri, 29 Jun 2018 03:30:50 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:57836 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753259AbeF2Has (ORCPT ); Fri, 29 Jun 2018 03:30:48 -0400 Received: from hsi-kbw-5-158-153-55.hsi19.kabel-badenwuerttemberg.de ([5.158.153.55] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fYnrD-0002HP-VV; Fri, 29 Jun 2018 09:30:16 +0200 Date: Fri, 29 Jun 2018 09:30:10 +0200 (CEST) From: Thomas Gleixner To: Pavel Tatashin cc: Steven Sistare , Daniel Jordan , linux@armlinux.org.uk, Martin Schwidefsky , Heiko Carstens , John Stultz , sboyd@codeaurora.org, x86@kernel.org, LKML , mingo@redhat.com, "H. Peter Anvin" , douly.fnst@cn.fujitsu.com, Peter Zijlstra , Prarit Bhargava , feng.tang@intel.com, Petr Mladek , gnomes@lxorguk.ukuu.org.uk, linux-s390@vger.kernel.org, andriy.shevchenko@linux.intel.com, boris.ostrovsky@oracle.com, pbonzini@redhat.com Subject: Re: [PATCH v12 09/11] x86/tsc: prepare for early sched_clock In-Reply-To: Message-ID: References: <20180621212518.19914-1-pasha.tatashin@oracle.com> <20180621212518.19914-10-pasha.tatashin@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, 28 Jun 2018, Pavel Tatashin wrote: > On Thu, Jun 28, 2018 at 11:23 AM Thomas Gleixner wrote: > Hi Thomas, > > In addition to above, we have xen hvm: > > setup_arch() > ... > init_hypervisor_platform(); > x86_init.hyper.init_platform(); > xen_hvm_guest_init() > xen_hvm_init_time_ops(); Duh. Missed that completely. > ... > tsc_early_delay_calibrate(); > tsc_khz = x86_platform.calibrate_tsc(); == xen_tsc_khz() > ... > > Which works early. > > So, what should we do with xen, which seems to be the only platform > that would provide different tsc frequency early and late, because of > different calibration method? Fix it? I have no idea why XEN has two variants of the scheme and I neither have a clue why the KVM clock stuff is late. Thanks, tglx