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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4F26C001B1 for ; Mon, 3 Jul 2023 15:53:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230377AbjGCPxa (ORCPT ); Mon, 3 Jul 2023 11:53:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230052AbjGCPx2 (ORCPT ); Mon, 3 Jul 2023 11:53:28 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C264CE54; Mon, 3 Jul 2023 08:53:27 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 539802F4; Mon, 3 Jul 2023 08:54:10 -0700 (PDT) Received: from [10.57.27.93] (unknown [10.57.27.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1986B3F663; Mon, 3 Jul 2023 08:53:24 -0700 (PDT) Message-ID: Date: Mon, 3 Jul 2023 16:53:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v2 05/17] trace: energy_model: Add trace event for EM runtime modifications Content-Language: en-US To: Dietmar Eggemann Cc: rui.zhang@intel.com, amit.kucheria@verdurent.com, amit.kachhap@gmail.com, daniel.lezcano@linaro.org, viresh.kumar@linaro.org, len.brown@intel.com, pavel@ucw.cz, Pierre.Gondois@arm.com, ionela.voinescu@arm.com, rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rafael@kernel.org References: <20230512095743.3393563-1-lukasz.luba@arm.com> <20230512095743.3393563-6-lukasz.luba@arm.com> <3ed3c9a0-8aed-02ad-b7f0-69200441a994@arm.com> From: Lukasz Luba In-Reply-To: <3ed3c9a0-8aed-02ad-b7f0-69200441a994@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/30/23 11:03, Dietmar Eggemann wrote: > On 12/05/2023 11:57, Lukasz Luba wrote: >> The Energy Model (EM) supports runtime modifications. Track the changes >> in order to do post-processing analysis. Don't use arrays in the trace >> event, since they are not properly supported by the tools. Instead use >> simple "unroll" with emitting the trace event for each EM array entry >> with proper ID information. The older debugging mechanism which was >> the simple debugfs which dumping the EM content won't be sufficient for >> the modifiable EM purpose. This trace event mechanism would address the >> needs. > > Do we really need a full trace_event for this? Can we not follow the > task scheduler rule which says no new trace_events and use a trace_point > here? The footprint in the kernel would be so much smaller. > > E.g. pelt_cfs_tp > > 0 sched.h 694 DECLARE_TRACE(pelt_cfs_tp, > 1 core.c 106 EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_cfs_tp); > 2 fair.c 3937 trace_pelt_cfs_tp(cfs_rq); > > And then this patch should be after the section with the functional changes. > > [...] I agree. I will change that approach and create tracepoint. Also, I'll move it to the patch at the end of the functional changes.