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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS 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 3EBDCC43441 for ; Thu, 29 Nov 2018 01:12:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAB8220863 for ; Thu, 29 Nov 2018 01:12:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="MYbRLwA9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAB8220863 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 S1727022AbeK2MQA (ORCPT ); Thu, 29 Nov 2018 07:16:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:54674 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbeK2MQA (ORCPT ); Thu, 29 Nov 2018 07:16:00 -0500 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 17F22206B6; Thu, 29 Nov 2018 01:12:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543453946; bh=3T6rMB0XvE37yr31GYVP2uvaQsuhFoBEKdGv1wB3dCw=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=MYbRLwA9BKu7e4ZFaqD/KP1mwbpa92UsoPMxti4Q/T1wdYrzS45QhVwwYyyknqj3T 5gSSiAdteTH1grLUlcDLd1uPPxs514MynB1hleU0Omj8/tH0Lws2mzrTcvDuJUphK9 AVKwjeVMXZI4m/zcFozIYHDCYUn6FcocWfIqB+EE= Message-ID: <1543453945.4149.6.camel@kernel.org> Subject: Re: [PATCH v7 09/16] tracing: Add hist trigger snapshot() action test case 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 Date: Wed, 28 Nov 2018 19:12:25 -0600 In-Reply-To: <20181128111558.5869fa4be7104314e833a801@kernel.org> References: <20181126220332.215b461779d1d57f37b46e20@kernel.org> <1543359225.4223.5.camel@kernel.org> <20181128111558.5869fa4be7104314e833a801@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 Wed, 2018-11-28 at 11:15 +0900, Masami Hiramatsu wrote: > Hi Tom, > > On Tue, 27 Nov 2018 16:53:45 -0600 > Tom Zanussi wrote: > > > > > +ping $LOCALHOST -c 3 > > > > +nice -n 1 ping $LOCALHOST -c 3 > > > > + > > > > +echo 0 > /sys/kernel/debug/tracing/events/sched/enable > > > > > > Shouldn't we stop tracing instead of disabling the event? > > > > > > > This is just reversing the enable, so should be fine, but I can > > stop > > tracing instead if you prefer. > > Oops, maybe we have to check the difference between event enabling > and > trace enabling. > echo 0 > tracing_on will stop writing ring buffer, but event may > continue > to be called. Does this mean hist will be updated? (and I guess > preferrable > behavior is to stop hist too, isn't it?) > For this test case, we're only enabling the sched events so we have something in the snapshot buffer to verify that the snapshot worked, so either should work for this purpose. The triggers are supposed to work even if nothing is being logged to the ring buffer, so the hist triggers updating when tracing to the buffers is disabled is consistent with that... Tom > Thank you, > >