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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED 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 1B4F7C5CFEB for ; Mon, 9 Jul 2018 18:25:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C053C208E2 for ; Mon, 9 Jul 2018 18:25:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Qrm1SlQo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C053C208E2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933340AbeGISZj (ORCPT ); Mon, 9 Jul 2018 14:25:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:34326 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932872AbeGISZi (ORCPT ); Mon, 9 Jul 2018 14:25:38 -0400 Received: from tzanussi-mobl (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9CDF7208E1; Mon, 9 Jul 2018 18:25:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1531160737; bh=j5gbrZknnsZAdkB5FUTqnSynrxZpvgVQlz1VuesBGvc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Qrm1SlQox7CHNDQiRkneLEJK/rD40/bFIWI6A7LY4AkbXRD/rxEIKDGvJUiMGkzZn HEKz5gDU7cG6W4pyeEOMxl2QEUuVmIZxcW6ZMftmC1XVWQcOsHJWWUNFQS/mHyeEh8 SD5zOcccJ7XQ3H4HXIH0yY4n+vOrJQAXueehd+SQ= Message-ID: <1531160735.20374.17.camel@kernel.org> Subject: Re: [PATCH v2 0/7] tracing: Hist trigger snapshot and onchange additions From: Tom Zanussi To: Masami Hiramatsu Cc: rostedt@goodmis.org, tglx@linutronix.de, namhyung@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel@joelfernandes.org, mathieu.desnoyers@efficios.com, julia@ni.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Tom Zanussi Date: Mon, 09 Jul 2018 13:25:35 -0500 In-Reply-To: <20180708000006.5b93884b8123392ab2446809@kernel.org> References: <20180708000006.5b93884b8123392ab2446809@kernel.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.1-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Masami, On Sun, 2018-07-08 at 00:00 +0900, Masami Hiramatsu wrote: > Hi Tom, > > On Mon, 2 Jul 2018 15:22:19 -0500 > Tom Zanussi wrote: > > > From: Tom Zanussi > > > > Hi, > > > > This is v2 of the hist trigger snapshot and onchange additions > > patchset. It adds a couple fixes to problems flagged by the kbuild > > test robot, but is otherwise the same as v1. > > > > Changes since v1: > > > > - added missing tracing_cond_snapshot_data() definition for when > > CONFIG_TRACER_SNAPSHOT not defined > > - removed an unnecessary WARN_ON() in track_data_snapshot_print() > > > > > > Original text: > > > > This patchset adds some useful new functions to the hist > > trigger code: a snapshot action and an onchange handler. > > > > In order to make it easier to add these and in the process make the > > code more generic, I separated the code into explicit 'handlers' > > and > > 'actions', handlers being things like 'onmax' and 'onchange', and > > 'actions' being things like 'take a snapshot' or 'save some > > fields'. > > Sounds great! > > By the way, it seems that nowadays the syntax of trigger is > very complicated. For example, we can set some 'actions' without > handlers, but this introduce new 'handlers' on it. > > Could you consider not just extending it, but refactor it from > the viewpoint of consistent and extensible syntax? > > e.g. if we support > > if > > syntax, why we can not do > > onchange() It seems that doing this would restrict you to only one handler e.g. you could no longer do something like: ...:onchange($var1).save(...):onmax($var2).snapshot() I'm not sure how you would do that with your syntax. On the other hand, if the most common use case is just a single handler along with one or more actions, I think it would make sense to provide a shorthand like you describe which just gets translated into the longer more explicit form. Or were you thinking of something more radical? Thanks, Tom >