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 45C13C433F5 for ; Wed, 27 Apr 2022 07:44:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359024AbiD0HsA (ORCPT ); Wed, 27 Apr 2022 03:48:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359023AbiD0Hrz (ORCPT ); Wed, 27 Apr 2022 03:47:55 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35D391594A6 for ; Wed, 27 Apr 2022 00:44:43 -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 ams.source.kernel.org (Postfix) with ESMTPS id D4F30B82522 for ; Wed, 27 Apr 2022 07:44:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03C78C385A9; Wed, 27 Apr 2022 07:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651045480; bh=I18bs66G2uf5DPVlbIEaZXD74gjZ9PfE8Eqt8iUP8H0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=behZyIvQY9Orw+SuOUoSnrENbyYurLUx8yzQRGdfUiL6S7YhOL5uQAdTr2+F3TqIq 0W+NlnK7tVCl8dWx0oXmNt2qPTjS3G5sgjQYfg2C01dccSf1vkUUZ/3xoXa9ahR+9b MV3r/CbO5C45QHgMfy/7OeDmyh3NjOzHQPz9eDvU= Date: Wed, 27 Apr 2022 09:44:37 +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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220427073551.19032-1-lukasz.luba@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 :(