From patchwork Thu Apr 30 16:18:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 11520859 X-Patchwork-Delegate: daniel.lezcano@linaro.org 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 0BD55913 for ; Thu, 30 Apr 2020 16:18:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E914D2173E for ; Thu, 30 Apr 2020 16:18:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588263520; bh=lW4zzFS0G9Wi4Z0P+nqG08m6PRjTTMBcjkMLSKAEx/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WxEV4VUdQSJJPOCmRyjrTVJoloqQG9oW6/IjGZgMj8PpF+Si/Mr1RwOuD+nSGyK9c p5Afy7jMxmFmJjkKbNvNy5shWBo49wa7xQuGbQ0x3xmDIpqOTlDm4q1FUMbem+/5/l R7H9kulj2VFpydC9RNDJIZPh2tlRb3jV65lmTAnc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728148AbgD3QSj (ORCPT ); Thu, 30 Apr 2020 12:18:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:58578 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726420AbgD3QSi (ORCPT ); Thu, 30 Apr 2020 12:18:38 -0400 Received: from mail.kernel.org (ip5f5ad5c5.dynamic.kabel-deutschland.de [95.90.213.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A560320873; Thu, 30 Apr 2020 16:18:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588263517; bh=lW4zzFS0G9Wi4Z0P+nqG08m6PRjTTMBcjkMLSKAEx/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t615eT3Q9pNpfUIrouBfac8mgll8VUS4jr3Ag7enyIc+LVo6TA9j3lMsuJE9cQQfz sf9wlQhSNxFOavyUaeU7+062U1oEI3YBwpstTJ/7fZTx03yIZqvRcaMolvo/ohpyig cmqXaXddzzJQ9zOGjwxL1N0Mwus6QNxjBg+E8ROc= Received: from mchehab by mail.kernel.org with local (Exim 4.92.3) (envelope-from ) id 1jUBtT-00Axge-S6; Thu, 30 Apr 2020 18:18:35 +0200 From: Mauro Carvalho Chehab To: Linux Doc Mailing List Cc: Mauro Carvalho Chehab , linux-kernel@vger.kernel.org, Jonathan Corbet , Amit Daniel Kachhap , Daniel Lezcano , Viresh Kumar , Javi Merino , linux-pm@vger.kernel.org Subject: [PATCH v4 01/19] docs: thermal: convert cpu-idle-cooling.rst to ReST Date: Thu, 30 Apr 2020 18:18:15 +0200 Message-Id: <617873f33407a764671be95d4ee15afa6027c924.1588263270.git.mchehab+huawei@kernel.org> X-Mailer: git-send-email 2.25.4 In-Reply-To: References: MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Despite being named with .rst extension, this file doesn't match the ReST standard. It actually causes a crash at Sphinx: Sphinx parallel build error: docutils.utils.SystemMessage: /devel/v4l/docs/Documentation/driver-api/thermal/cpu-idle-cooling.rst:69: (SEVERE/4) Unexpected section title. Add needed markups for it to be properly parsed. While here, add it to the thermal index.rst. Signed-off-by: Mauro Carvalho Chehab --- .../driver-api/thermal/cpu-idle-cooling.rst | 18 ++++++++++++------ Documentation/driver-api/thermal/index.rst | 1 + 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/Documentation/driver-api/thermal/cpu-idle-cooling.rst b/Documentation/driver-api/thermal/cpu-idle-cooling.rst index a1c3edecae00..b5a4544af004 100644 --- a/Documentation/driver-api/thermal/cpu-idle-cooling.rst +++ b/Documentation/driver-api/thermal/cpu-idle-cooling.rst @@ -1,3 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +CPU Idle Cooling +================ + Situation: ---------- @@ -45,7 +51,7 @@ idle state target residency, we lead to dropping the static and the dynamic leakage for this period (modulo the energy needed to enter this state). So the sustainable power with idle cycles has a linear relation with the OPP’s sustainable power and can be computed with a -coefficient similar to: +coefficient similar to:: Power(IdleCycle) = Coef x Power(OPP) @@ -136,7 +142,7 @@ Power considerations -------------------- When we reach the thermal trip point, we have to sustain a specified -power for a specific temperature but at this time we consume: +power for a specific temperature but at this time we consume:: Power = Capacitance x Voltage^2 x Frequency x Utilisation @@ -145,7 +151,7 @@ wrong in the system setup). The ‘Capacitance’ and ‘Utilisation’ are a fixed value, ‘Voltage’ and the ‘Frequency’ are fixed artificially because we don’t want to change the OPP. We can group the ‘Capacitance’ and the ‘Utilisation’ into a single term which is the -‘Dynamic Power Coefficient (Cdyn)’ Simplifying the above, we have: +‘Dynamic Power Coefficient (Cdyn)’ Simplifying the above, we have:: Pdyn = Cdyn x Voltage^2 x Frequency @@ -154,7 +160,7 @@ in order to target the sustainable power defined in the device tree. So with the idle injection mechanism, we want an average power (Ptarget) resulting in an amount of time running at full power on a specific OPP and idle another amount of time. That could be put in a -equation: +equation:: P(opp)target = ((Trunning x (P(opp)running) + (Tidle x P(opp)idle)) / (Trunning + Tidle) @@ -165,7 +171,7 @@ equation: At this point if we know the running period for the CPU, that gives us the idle injection we need. Alternatively if we have the idle -injection duration, we can compute the running duration with: +injection duration, we can compute the running duration with:: Trunning = Tidle / ((P(opp)running / P(opp)target) - 1) @@ -188,7 +194,7 @@ However, in this demonstration we ignore three aspects: target residency, otherwise we end up consuming more energy and potentially invert the mitigation effect -So the final equation is: +So the final equation is:: Trunning = (Tidle - Twakeup ) x (((P(opp)dyn + P(opp)static ) - P(opp)target) / P(opp)target ) diff --git a/Documentation/driver-api/thermal/index.rst b/Documentation/driver-api/thermal/index.rst index 5ba61d19c6ae..4cb0b9b6bfb8 100644 --- a/Documentation/driver-api/thermal/index.rst +++ b/Documentation/driver-api/thermal/index.rst @@ -8,6 +8,7 @@ Thermal :maxdepth: 1 cpu-cooling-api + cpu-idle-cooling sysfs-api power_allocator