From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F40DC282C2 for ; Wed, 13 Feb 2019 06:29:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16C84222C0 for ; Wed, 13 Feb 2019 06:29:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="X+ri0rsI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732924AbfBMG3S (ORCPT ); Wed, 13 Feb 2019 01:29:18 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:35483 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727172AbfBMG3S (ORCPT ); Wed, 13 Feb 2019 01:29:18 -0500 Received: by mail-pf1-f194.google.com with SMTP id z15so705875pfa.2 for ; Tue, 12 Feb 2019 22:29:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=sv9/LKEnpYwGLMUP3w3TvtBoynYhwg7Tk2v6eo4unZY=; b=X+ri0rsITtoA/OYe22sGYeFft2TPL/q4wEy18AtjSAndTi9CIfufrr1A8Y/Jtm07GQ gbaCEAauDg9xk0aLa+XceMUfN0S9dg6DK9s1t3f1xevT3hjLnRUkcqZ8LNJceSa9wzAd Sq4k0Dr07STZ2WdGPcPUHX4LKu5q851F0HvwTuPWG5079Yg4B9TYRrNSjJlJ4+KGRFpZ qDvaNIA5WbpGxM+VuEUaaVhLHk5hG0qfANFypLiYua4YL1P67UilGHZ99Fc/fWfvPUtW /ufX+BwqI4/aH4vYTftaHqRgEHbMKjf1AsE+uDGivUo49DBA+db9c3odpDQlo7ONw7q0 gP6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=sv9/LKEnpYwGLMUP3w3TvtBoynYhwg7Tk2v6eo4unZY=; b=f2/pqEsB7bzJLqg0iHE2xnGCLLqNSBw66GfjhugSuyLN9W6RBoavVDeOEGEm0VlH9U kKqA79ASMrz4OtEHy5t4231Mo/Zv8k76CAtDWjpHQbzuO9sO+qcuOv9e3VTFF9iaq4yr nkMg6nM4+i80VgqgdUeECKhGTzqEux9tMI6o9di83J6yp1j+hoCII/xOpavePv70mJZn AANLMrHRmVE+9mAD542oJhivZlS9Yd0/ZZdZV/d8BRbLLsMs1WtyMGpQFr7s1g8I19sF 0519xubUo5Nb5MpHMyxBZDvUHf3HBjvtIoW/isfULBK8B8+2Yv5wtlSvmdCsDyCf3gG0 VRVQ== X-Gm-Message-State: AHQUAubHR+POBYdqzBqrrWaulUMhBoC/HasIolCMFV7wNeyjtzgDJLZD z5JLD8rJsroCknUpF3WaESw= X-Google-Smtp-Source: AHgI3IYYHyd+C3sXrRh1nVJLSR/J79qhGqpSFyc1J7/b64pihYUeHLbslTnkx9J+1wy3glA97nAi+w== X-Received: by 2002:a62:3811:: with SMTP id f17mr8193207pfa.206.1550039357653; Tue, 12 Feb 2019 22:29:17 -0800 (PST) Received: from localhost ([39.7.15.189]) by smtp.gmail.com with ESMTPSA id d21sm17562572pgv.37.2019.02.12.22.29.16 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 12 Feb 2019 22:29:16 -0800 (PST) Date: Wed, 13 Feb 2019 15:29:12 +0900 From: Sergey Senozhatsky To: xiang xiao Cc: Steven Rostedt , Petr Mladek , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Xiang Xiao Subject: Re: [PATCH] printk: add KERN_NOTIME to skip the timestamp Message-ID: <20190213062912.GA23233@jagdpanzerIV> References: <1549995065-27597-1-git-send-email-xiaoxiang@xiaomi.com> <20190212144606.4b7cf0f8@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (02/13/19 14:19), xiang xiao wrote: > Here is my case: > 1.A small MCU(Cortex M4) in SoC run RTOS > 2.RTOS append timestamp to log for the accurate timing > 3.RTOS send log to Linux kernel when buffer exceed the threshold > 4.Kernel call printk to dump the received buffer > So I want that printk skip the timestamp here. > > > If anything, I would probably prefer that we export whether > > time is being printed, and have the caller not print time if printk is > > doing it already, than to add the complexity into printk itself. > > Actually, the timestamp of our initial implementation like your > suggestion come from printk, cat /sys/module/printk/parameters/time ? Y - we add time prefix N - we don't add time prefix -ss