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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_MED,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 9C26CC072B5 for ; Fri, 24 May 2019 15:48:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71AE4217D7 for ; Fri, 24 May 2019 15:48:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="M4QUoyns" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390194AbfEXPs6 (ORCPT ); Fri, 24 May 2019 11:48:58 -0400 Received: from mail-pl1-f178.google.com ([209.85.214.178]:39134 "EHLO mail-pl1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389079AbfEXPs6 (ORCPT ); Fri, 24 May 2019 11:48:58 -0400 Received: by mail-pl1-f178.google.com with SMTP id g9so4325442plm.6 for ; Fri, 24 May 2019 08:48:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=m6gKYz7wkMPGTWMNM0luL5MmLCYmBXD7EJslrvo/nuI=; b=M4QUoyns4jSgst9lr4PwNHSUiJULHUtmzpXOWndjKxy4R6IxbXauo5MLpecOAGHzVd 7txaUQB3BUrcseBlcRGnzxH6ugyzMaXst4C4Xf/PfNBsOQJUsgDQrawrNBRwa+j+pzai dc4HndGGbrZHemNVGV8OQfhSl+KDkQ2iKoDV5zOceF3NFyMJM6zYHFV4aTGB0bFXZ3MB kttg0HiaviV/rHqN/nX4fIjA3SxT730gE4iDAoHjprM+Ib+UJL66opcCEwtwIwLXd4dW ICuaRA9wXlfR87lMl0KpAaevH/emFdCSUuqbDqXhvfdMdj59LhoIpW+3yuk/OsqdoHUO lPXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=m6gKYz7wkMPGTWMNM0luL5MmLCYmBXD7EJslrvo/nuI=; b=pI8hbRY4Wn5GJblWJPA7yJ1rec6eA1TD/lWzc53voClwv7TYP5l9dsOuWXNRupUwN9 FgsKT3yWNPU3dJb+3g3ZnRr35IDa60JcSLvhWuzYuI7Kq2bpa4kipPB6AK/hlx3qcQmj 2fKyWB0R6RAoC9bDNQtXkZuFp6tZyS9pdV4LIoUx/F93CfAarf9tO+sMakdbOzU0V17A lFvBShjb6N5wzU0P5umqJqy8ap/t5qSuQhMzbqp+ZggzfHHXP47lSUVsdkg72cfrGM2c tof7V8D4Cv6IbmU+MqoyifgfWfmDyyg/OP26RMlivd6w84yxxsaaaHsiUZREPVi37EU0 E5Rg== X-Gm-Message-State: APjAAAVFCdHg6HQZel6Ypoj735aXzU9PY1x1xdzd4Eihzqh+0J1XtiZc 2Jl/ti1U99x1zKK3dh+qk6CuOWpE2xt/GOVBggwLvPEjbho= X-Google-Smtp-Source: APXvYqzt+tANlU8Rah8eIjD2c2ndYNOEsbqihsbGfnF3jgLGWI/bEJDx77myq9kw+EFJoQEvuqsFy2MjrsQQ7oENbaY= X-Received: by 2002:a17:902:7486:: with SMTP id h6mr11158387pll.262.1558712936535; Fri, 24 May 2019 08:48:56 -0700 (PDT) MIME-Version: 1.0 References: <20190329125258.2c6fe0cb@gandalf.local.home> <20190401222056.3da6e7a7@oasis.local.home> <20190524110048.142efd44@gandalf.local.home> <20190524112457.58b24d89@gandalf.local.home> In-Reply-To: <20190524112457.58b24d89@gandalf.local.home> From: Jason Behmer Date: Fri, 24 May 2019 08:48:44 -0700 Message-ID: Subject: Re: Nested events with zero deltas, can use absolute timestamps instead? To: Steven Rostedt Cc: tom.zanussi@linux.intel.com, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 24, 2019 at 8:25 AM Steven Rostedt wrote: > > On Fri, 24 May 2019 08:11:12 -0700 > Jason Behmer wrote: > > > > > What do you think of that? > > > > > > I don't think that's confusing if its well documented. Have the user > > > flag called "force_absolute_timestamps", that way it's not something > > > that the user will think that we wont have absolute timestamps if it is > > > zero. Have the documentation say: > > > > > > Various utilities within the tracing system require that the ring > > > buffer uses absolute timestamps. But you may force the ring buffer to > > > always use it, which will give you unique timings with nested tracing > > > at the cost of more usage in the ring buffer. > > > > > > -- Steve > > > > Ah, I was thinking of doing this within the existing timestamp_mode > > config file. Having a separate file does make it much less confusing. > > Not a separate file, but a new tracing option. > > -- Steve Sorry, I'm not sure I follow. By new tracing option do you mean a new option in the timestamp_mode file? I guess in that case would that still be the only writable option? You could write 1/0 to the file which would turn on/off force_absolute_timestamps, and reading the file would show which of absolute, delta, and force_absolute was set? Or did you mean something else by tracing option?