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 D7CC7C433F5 for ; Wed, 23 Feb 2022 00:40:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236434AbiBWAlL (ORCPT ); Tue, 22 Feb 2022 19:41:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231518AbiBWAlL (ORCPT ); Tue, 22 Feb 2022 19:41:11 -0500 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D19735F8F7; Tue, 22 Feb 2022 16:40:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1645576844; x=1677112844; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=bXG/hqPanWAZqS1VkKyT5WERuxbLoNAjWQs8L+yqxEg=; b=YftGCQmzBOAr6wQwUjZ6cNYRcnQZMx1kGLyYkYhh9MC/xxUIosKClf/G 3U4T1VZz5hmv3ymt1vfy7KqgePwItipphY8T4wQ8ToCJ3lXzWuGxoj/59 0FqWkIiw9cnRU5meORy1qWOPAmzgkNEgqlfIG/2Zu2auln5JQ+BVJPqO1 EoNF6tUkIEPnICWeZefEnRAYTaz5s8YofpFOY6b1hikZ1+mYTxjARoLhX 27dQn3481V5C1UjQ2X4qzUrNi31u5BuUL9uCwc6AP0n+tTcjgLlWdb5TJ 075q/2b3BmGemlpYdCQmSx18sbXGeb6qds8LedT5wVYeCzfze13RkosNo g==; X-IronPort-AV: E=McAfee;i="6200,9189,10266"; a="235360402" X-IronPort-AV: E=Sophos;i="5.88,389,1635231600"; d="scan'208";a="235360402" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2022 16:40:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,389,1635231600"; d="scan'208";a="776497120" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.146.189]) by fmsmga006.fm.intel.com with ESMTP; 22 Feb 2022 16:40:41 -0800 Date: Wed, 23 Feb 2022 08:40:41 +0800 From: Feng Tang To: srinivas pandruvada Cc: Doug Smythies , "Rafael J. Wysocki" , "Zhang, Rui" , Thomas Gleixner , "paulmck@kernel.org" , "stable@vger.kernel.org" , "x86@kernel.org" , "linux-pm@vger.kernel.org" Subject: Re: CPU excessively long times between frequency scaling driver calls - bisected Message-ID: <20220223004041.GA4548@shbuild999.sh.intel.com> References: <20220208091525.GA7898@shbuild999.sh.intel.com> <20220222073435.GB78951@shbuild999.sh.intel.com> <24f7d485dc60ba3ed5938230f477bf22a220d596.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <24f7d485dc60ba3ed5938230f477bf22a220d596.camel@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Feb 22, 2022 at 04:32:29PM -0800, srinivas pandruvada wrote: > Hi Doug, > > On Tue, 2022-02-22 at 16:07 -0800, Doug Smythies wrote: > > Hi All, > > > > I am about 1/2 way through testing Feng's "hacky debug patch", > > let me know if I am wasting my time, and I'll abort. So far, it > > works fine. > This just proves that if you add some callback during long idle, you > will reach a less aggressive p-state. I think you already proved that > with your results below showing 1W less average power ("Kernel 5.17-rc3 > + Feng patch (6 samples at 300 sec per"). > > Rafael replied with one possible option. Alternatively when planing to > enter deep idle, set P-state to min with a callback like we do in > offline callback. Yes, if the system is going to idle, it makes sense to goto a lower cpufreq first (also what my debug patch will essentially lead to). Given cprfreq-util's normal running frequency is every 10ms, doing this before entering idle is not a big extra burden. Thanks, Feng > So we need to think about a proper solution for this. > > Thanks, > Srinivas