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 X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E89EC47076 for ; Fri, 21 May 2021 16:54:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F28E4613D9 for ; Fri, 21 May 2021 16:54:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237833AbhEUQ4T (ORCPT ); Fri, 21 May 2021 12:56:19 -0400 Received: from foss.arm.com ([217.140.110.172]:51560 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237802AbhEUQ4Q (ORCPT ); Fri, 21 May 2021 12:56:16 -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 B4A5E1480; Fri, 21 May 2021 09:54:52 -0700 (PDT) Received: from e120877-lin.cambridge.arm.com (e120877-lin.cambridge.arm.com [10.1.194.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5FD103F73D; Fri, 21 May 2021 09:54:51 -0700 (PDT) From: Vincent Donnefort To: peterz@infradead.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, vincent.guittot@linaro.org, qperret@google.com Cc: linux-kernel@vger.kernel.org, ionela.voinescu@arm.com, lukasz.luba@arm.com, dietmar.eggemann@arm.com, Vincent Donnefort Subject: [PATCH v2 1/3] PM / EM: Fix inefficient state detection Date: Fri, 21 May 2021 17:54:22 +0100 Message-Id: <1621616064-340235-2-git-send-email-vincent.donnefort@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1621616064-340235-1-git-send-email-vincent.donnefort@arm.com> References: <1621616064-340235-1-git-send-email-vincent.donnefort@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, a debug message is printed if an inefficient state is detected in the Energy Model. Unfortunately, it won't detect if the first state is inefficient or if two successive states are. Fix this behavior. Signed-off-by: Vincent Donnefort diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 0c620eb..c4871a8 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -107,8 +107,7 @@ static void em_debug_remove_pd(struct device *dev) {} static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, int nr_states, struct em_data_callback *cb) { - unsigned long opp_eff, prev_opp_eff = ULONG_MAX; - unsigned long power, freq, prev_freq = 0; + unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX; struct em_perf_state *table; int i, ret; u64 fmax; @@ -153,25 +152,19 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, table[i].power = power; table[i].frequency = prev_freq = freq; - - /* - * The hertz/watts efficiency ratio should decrease as the - * frequency grows on sane platforms. But this isn't always - * true in practice so warn the user if a higher OPP is more - * power efficient than a lower one. - */ - opp_eff = freq / power; - if (opp_eff >= prev_opp_eff) - dev_dbg(dev, "EM: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n", - i, i - 1); - prev_opp_eff = opp_eff; } /* Compute the cost of each performance state. */ fmax = (u64) table[nr_states - 1].frequency; - for (i = 0; i < nr_states; i++) { + for (i = nr_states - 1; i >= 0; i--) { table[i].cost = div64_u64(fmax * table[i].power, table[i].frequency); + if (table[i].cost >= prev_cost) { + dev_dbg(dev, "EM: OPP:%lu is inefficient\n", + table[i].frequency); + } else { + prev_cost = table[i].cost; + } } pd->table = table; -- 2.7.4