Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp7322018imu; Thu, 27 Dec 2018 17:46:16 -0800 (PST) X-Google-Smtp-Source: ALg8bN4OL3BNFxOkDPuKQPEwt8UX6QqzDoHYXxlbNKNQtRtq+XISmeaDreqSB3PJ5fpu8tRoLuVZ X-Received: by 2002:a63:f047:: with SMTP id s7mr24611719pgj.441.1545961575988; Thu, 27 Dec 2018 17:46:15 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1545961575; cv=none; d=google.com; s=arc-20160816; b=kF89IkScsJ0abeYHrC8fwuFiJ7S+KG1Ha6XpTpML8zN6F0wgd/Kv//0Pqhcm+ObU43 kvtncZoEIlRt8PVNHwMyUa+rfQTTCjlgx9ak5KWVNtxW9t0WYCcEaQy4FYWF8++sWeFB 8mGVPwWPNIQubhS7H5eH30a7McTV1iD7C/60rX4GPW5pbi9pZqzwkMXsluOyYk7PMO7+ 9Ebho5vmNmWpDkfCB6xcsA7mRkoBb1FnpR7MgxCwuUQHlY3YoCkGZz75oSAvDrkvn4Sx 2YZ4n9wSOmOoxPRd54j76x8eQ29IgvEe49V1NJF7S10xIV0aLoLhV8qz+pXl3l17Eurh SSww== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:message-id:in-reply-to:date :references:subject:cc:to:from; bh=Tlh8CxAbPxEKdQ+ZeElbJ0cn/0rbWHcP13T2Z3pq7wQ=; b=MsHacYDKeJAO5scVlnhOzO16odp8FrQMazEo63qn4a6KIvcvsiZ5hmXSL8VIC5/cTv n2l2yshXfkK2Jm4tw5O+T4nmW1PyAlGijnN4IIhF/iAO/lGJJfz14vsTUwmYH2kII3ul OYPuMOAToqk9ypJF07unake62TCgGXA5g+C+ottv97ZWrfpwcs/RpwdlEoQU1NqwtS/A pU3W7wLUFMAbeZVOAwFidhdlm6gVItf7LLOaMju87v1xoglRQ1vKP78xYxpLCBacpOCw xVze30OyZGZ1lLU+dTPgGfLRev6WMPyH1gej9DgKVAKYxkwAZo+uEVhxxwmVwUJN2fVY k7Zg== 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 v14si39791060pfc.76.2018.12.27.17.46.00; Thu, 27 Dec 2018 17:46:15 -0800 (PST) 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 S1725914AbeL0RfP (ORCPT + 99 others); Thu, 27 Dec 2018 12:35:15 -0500 Received: from albireo.enyo.de ([5.158.152.32]:48298 "EHLO albireo.enyo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725763AbeL0RfP (ORCPT ); Thu, 27 Dec 2018 12:35:15 -0500 Received: from [172.17.203.2] (helo=deneb.enyo.de) by albireo.enyo.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1gcZYv-0004uT-51; Thu, 27 Dec 2018 17:35:13 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.89) (envelope-from ) id 1gcZYv-0001TJ-0R; Thu, 27 Dec 2018 18:35:13 +0100 From: Florian Weimer To: Da Shi Cao Cc: linux-kernel@vger.kernel.org, linux-x86_64@vger.kernel.org Subject: Re: [BUG]Uncalibrated TSC is not accurate enough as a time keeper References: Date: Thu, 27 Dec 2018 18:35:13 +0100 In-Reply-To: (Da Shi Cao's message of "Sun, 23 Dec 2018 14:56:01 +0800") Message-ID: <874layvpny.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Da Shi Cao: > The cpu_khz and tsc_khz are now read directly by the cpuid > instruction, and they are deemed to be very accurate. But this is not > the case in our situation. The OS time lags behind about 8 seconds per > hour. The CPU information is as follows: Is virtualization involved? Do you use a vendor kernel? Note that is more or less dead, and your message to linux-kernel might get lost in the flood.