From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932512AbdCWAAy (ORCPT ); Wed, 22 Mar 2017 20:00:54 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:27087 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932466AbdCWAAr (ORCPT ); Wed, 22 Mar 2017 20:00:47 -0400 Subject: Re: [v1 0/9] Early boot time stamps for x86 To: Peter Zijlstra References: <1490214265-899964-1-git-send-email-pasha.tatashin@oracle.com> <20170322202807.y34mrortprg5pi43@hirez.programming.kicks-ass.net> Cc: x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com From: Pasha Tatashin Message-ID: Date: Wed, 22 Mar 2017 19:59:43 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170322202807.y34mrortprg5pi43@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, Thank you for looking at this patchset. Yes, I am certain it is 0 or near 0 on reset on this machine. Because, I actually wondered about it, and used stop watch as an alternative way to verify the result, twice. While, I suspect it is often the case that on reset tsc is 0, it is not really import, as the offset value is not the important part of the project. The important part is that we can cover the whole Linux boot process with timestamps, and know where spend time, and avoid regressions in the future. Thank you, Pasha On 2017-03-22 16:28, Peter Zijlstra wrote: > On Wed, Mar 22, 2017 at 04:24:16PM -0400, Pavel Tatashin wrote: >> - early tsc offset is 549s, so it took over 9 minutes to get through POST, >> and GRUB before starting linux > > Lol, how cute. You assume TSC starts at 0 on reset. >