From patchwork Thu Oct 8 17:04:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Luba X-Patchwork-Id: 11824235 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 016AD139F for ; Thu, 8 Oct 2020 17:04:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3156221FE for ; Thu, 8 Oct 2020 17:04:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730366AbgJHREv (ORCPT ); Thu, 8 Oct 2020 13:04:51 -0400 Received: from foss.arm.com ([217.140.110.172]:39566 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727698AbgJHREu (ORCPT ); Thu, 8 Oct 2020 13:04:50 -0400 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 6E597D6E; Thu, 8 Oct 2020 10:04:50 -0700 (PDT) Received: from e123648.arm.com (unknown [10.57.48.204]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1F7F43F802; Thu, 8 Oct 2020 10:04:44 -0700 (PDT) From: Lukasz Luba To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: daniel.lezcano@linaro.org, amitk@kernel.org, Dietmar.Eggemann@arm.com, lukasz.luba@arm.com, ionela.voinescu@arm.com Subject: [PATCH v2 1/2] thermal: power allocator: change the 'k_i' coefficient estimation Date: Thu, 8 Oct 2020 18:04:25 +0100 Message-Id: <20201008170426.465-2-lukasz.luba@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201008170426.465-1-lukasz.luba@arm.com> References: <20201008170426.465-1-lukasz.luba@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Intelligent Power Allocation (IPA) is built around the PID controller concept. The initialization code tries to setup the environment based on the information available in DT or estimate the value based on minimum power reported by each of the cooling device. The estimation will have an impact on the PID controller behaviour via the related 'k_po', 'k_pu', 'k_i' coefficients and also on the power budget calculation. This change prevents the situation when 'k_i' is relatively big compared to 'k_po' and 'k_pu' values. This might happen when the estimation for 'sustainable_power' returned small value, thus 'k_po' and 'k_pu' are small. Signed-off-by: Lukasz Luba Reviewed-by: Ionela Voinescu --- drivers/thermal/gov_power_allocator.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c index e566806f1550..aa35aa6c561c 100644 --- a/drivers/thermal/gov_power_allocator.c +++ b/drivers/thermal/gov_power_allocator.c @@ -132,6 +132,7 @@ static void estimate_pid_constants(struct thermal_zone_device *tz, int ret; int switch_on_temp; u32 temperature_threshold; + s32 k_i; ret = tz->ops->get_trip_temp(tz, trip_switch_on, &switch_on_temp); if (ret) @@ -157,8 +158,11 @@ static void estimate_pid_constants(struct thermal_zone_device *tz, tz->tzp->k_pu = int_to_frac(2 * sustainable_power) / temperature_threshold; - if (!tz->tzp->k_i || force) - tz->tzp->k_i = int_to_frac(10) / 1000; + if (!tz->tzp->k_i || force) { + k_i = tz->tzp->k_pu / 10; + tz->tzp->k_i = k_i > 0 ? k_i : 1; + } + /* * The default for k_d and integral_cutoff is 0, so we can * leave them as they are.