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 06695C433EF for ; Wed, 27 Apr 2022 07:58:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359206AbiD0IBd (ORCPT ); Wed, 27 Apr 2022 04:01:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350586AbiD0IBa (ORCPT ); Wed, 27 Apr 2022 04:01:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5156F517D2 for ; Wed, 27 Apr 2022 00:58:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E110A61BBD for ; Wed, 27 Apr 2022 07:58:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6642C385A7; Wed, 27 Apr 2022 07:58:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651046299; bh=mE6x4iTlX7XDpvguF39C/1/ZadyoBD4PGaWQhRwJ2XU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jUVjlRuT+7C7W2EzixGj/qPE71wC76XqDAimbEcmld5o7PIfZOW3oOLJ8vJiZyi+A bh+H+d2Se3rxAarHz7SnPeQYMZS8mq0fqDdSiOcg8l1BZKAxl6T94UsTXkLVWJyxLE QXYHIkXa678jDQwMH1lXis1t6DnDEzVqJTIjMsvs= Date: Wed, 27 Apr 2022 09:58:15 +0200 From: Greg KH To: Lukasz Luba Cc: linux-kernel@vger.kernel.org, sudeep.holla@arm.com, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, rafael@kernel.org, rostedt@goodmis.org, mingo@redhat.com Subject: Re: [PATCH v3] arch_topology: Trace the update thermal pressure Message-ID: References: <20220427073551.19032-1-lukasz.luba@arm.com> <38c8a684-5fcc-cfb3-424c-d353a7bafe03@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <38c8a684-5fcc-cfb3-424c-d353a7bafe03@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 27, 2022 at 08:52:50AM +0100, Lukasz Luba wrote: > > > On 4/27/22 08:44, Greg KH wrote: > > On Wed, Apr 27, 2022 at 08:35:51AM +0100, Lukasz Luba wrote: > > > Add trace event to capture the moment of the call for updating the thermal > > > pressure value. It's helpful to investigate how often those events occur > > > in a system dealing with throttling. This trace event is needed since the > > > old 'cdev_update' might not be used by some drivers. > > > > > > The old 'cdev_update' trace event only provides a cooling state > > > value: [0, n]. That state value then needs additional tools to translate > > > it: state -> freq -> capacity -> thermal pressure. This new trace event > > > just stores proper thermal pressure value in the trace buffer, no need > > > for additional logic. This is helpful for cooperation when someone can > > > simply sends to the list the trace buffer output from the platform (no > > > need from additional information from other subsystems). > > > > > > There are also platforms which due to some design reasons don't use > > > cooling devices and thus don't trigger old 'cdev_update' trace event. > > > They are also important and measuring latency for the thermal signal > > > raising/decaying characteristics is in scope. This new trace event > > > would cover them as well. > > > > > > We already have a trace point 'pelt_thermal_tp' which after a change to > > > trace event can be paired with this new 'thermal_pressure_update' and > > > derive more insight what is going on in the system under thermal pressure > > > (and why). > > > > > > Reported-by: kernel test robot > > > > The kernel test robot did not report that you needed to add a new trace > > event :( > > > > I got feedback from the test robot for v1, which figured out that > the riscv configuration is broken. You can find it here > https://lore.kernel.org/lkml/202204201654.vcszVDGb-lkp@intel.com/ > > So, I've added that tag following: > "If you fix the issue, kindly add following tag as appropriate" > > Should this only be honored when a patch actually got into next > and then following patch with a fix would have that tag? Yes. And you can mention it in the version information about what changed between each patch version below the --- line, but as is, you can see how this does not make sense. thanks, greg k-h