From patchwork Tue Apr 29 20:28:33 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stratos Karafotis X-Patchwork-Id: 4089191 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 368CDBFF02 for ; Tue, 29 Apr 2014 20:28:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5C18E20222 for ; Tue, 29 Apr 2014 20:28:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FCC2201CE for ; Tue, 29 Apr 2014 20:28:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757398AbaD2U2h (ORCPT ); Tue, 29 Apr 2014 16:28:37 -0400 Received: from sema.semaphore.gr ([78.46.194.137]:42434 "EHLO sema.semaphore.gr" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753522AbaD2U2g (ORCPT ); Tue, 29 Apr 2014 16:28:36 -0400 Received: from albert.lan (ppp079166106130.access.hol.gr [79.166.106.130]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: stratosk) by sema.semaphore.gr (Postfix) with ESMTPSA id 18CC6837F0; Tue, 29 Apr 2014 22:28:30 +0200 (CEST) Message-ID: <53600B71.2050904@semaphore.gr> Date: Tue, 29 Apr 2014 23:28:33 +0300 From: Stratos Karafotis User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" , Viresh Kumar CC: "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , LKML Subject: [PATCH] cpufreq: Break out early when frequency equals target_freq Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Many drivers keep frequencies in frequency table in ascending or descending order. When governor tries to change to policy->min or policy->max respectively then the cpufreq_frequency_table_target could return on first iteration. This will save some iteration cycles. So, break out early when a frequency in cpufreq_frequency_table equals to target one. Testing this during kernel compilation using ondemand governor with a frequency table in ascending order, the cpufreq_frequency_table_target returned early on the first iteration at about 30% of times called. Signed-off-by: Stratos Karafotis --- drivers/cpufreq/freq_table.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index 8e518c6..1632981 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -137,9 +137,13 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy, i = pos - table; if ((freq < policy->min) || (freq > policy->max)) continue; + if (freq == target_freq) { + optimal.driver_data = i; + break; + } switch (relation) { case CPUFREQ_RELATION_H: - if (freq <= target_freq) { + if (freq < target_freq) { if (freq >= optimal.frequency) { optimal.frequency = freq; optimal.driver_data = i; @@ -152,7 +156,7 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy, } break; case CPUFREQ_RELATION_L: - if (freq >= target_freq) { + if (freq > target_freq) { if (freq <= optimal.frequency) { optimal.frequency = freq; optimal.driver_data = i;