From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966740AbcA1NRs (ORCPT ); Thu, 28 Jan 2016 08:17:48 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47993 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933948AbcA1NRp (ORCPT ); Thu, 28 Jan 2016 08:17:45 -0500 Message-ID: <56AA14F6.7060802@redhat.com> Date: Thu, 28 Jan 2016 08:17:42 -0500 From: Prarit Bhargava User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Vasily Averin , linux-kernel@vger.kernel.org CC: John Stultz , Xunlei Pang , Thomas Gleixner , Baolin Wang , Andrew Morton , Greg Kroah-Hartman , Petr Mladek , Tejun Heo , Peter Hurley , Joe Perches Subject: Re: [PATCH] printk, allow different timestamps for printk.time [v2] References: <1453985029-25912-1-git-send-email-prarit@redhat.com> <56AA0F16.1020806@virtuozzo.com> In-Reply-To: <56AA0F16.1020806@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/2016 07:52 AM, Vasily Averin wrote: > Dear Prarit, > Hi Vasily, Thanks for your suggestions. > I have no objections about your patch, > bit in fact I doubt we really need to convert each timestamp in kernel logs. > How do you think is it probably better to convert only one timestamp per screen ? How do you measure a screen? :) > I.e. convert it in each 25th string only? While your suggestion does work for a flood of messages this will miss situations where an event occurred hours/minutes/seconds earlier leading to a panic. > Or just do it once per N seconds? I've tried several other versions of the patch and other userspace options (such as "date +%N > /tmp/kmsg" every second, setting up a timer to dump the real time, etc.). Assuming that the disks didn't die (which was also part of the problem I have seen) the printk buffer is finite in size and it is easy to fill the buffer if you're not careful. > And do not replace original timestamp but add converted one? I'm not sure I see the benefit of having two timestamps but if someone really wanted that I could add an additional patch to do it. At the end of the day I need to be able to determine in real time what happened on a system and to make that as easy as possible for a human to read. P.