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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 22F27C43381 for ; Tue, 26 Mar 2019 18:43:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5E26206DF for ; Tue, 26 Mar 2019 18:43:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="gww6filz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732647AbfCZSnt (ORCPT ); Tue, 26 Mar 2019 14:43:49 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:33727 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732561AbfCZSns (ORCPT ); Tue, 26 Mar 2019 14:43:48 -0400 Received: by mail-pl1-f193.google.com with SMTP id bg8so2038104plb.0 for ; Tue, 26 Mar 2019 11:43:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=vGHxDRbS/6yolL/adNeLRruWuHT6NB7eWlWIx8+XjvU=; b=gww6filzbPExhR6qzMRQnTCop6Av5na2TthQoV/QeGa67VXI9i/Z1BCgbLkvNzdrNU cP0Qyb606jhzgHXzKqPbY7fUXgbRDXbU/+dryjm8G8tYa0hPhNG5nDSKir3zMw6/Pl1H 70gsFon/xaML4byBDCpQfTkwbPtaef5dPGwTc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=vGHxDRbS/6yolL/adNeLRruWuHT6NB7eWlWIx8+XjvU=; b=BXoEwQve58TzdN5hIRP+lEAZncnWvsAz2UbW71b7/AR5SSwQP/qaOK9ZK2U2aMCVnH Mqzlp3pAOuFv7KL/eSSJRwrMcZ1g0EqgxHmGQQ+o1Qk6rLHFbGZDNuYdzrIYQdESRzYD IrMyfB2xVqmkyHi7xPKz3U/h3pA2pB1kBy6eOj0sincnV0TbQJsfpVnElynyvGX7KHhd qaX3kimUL1J8pyHIbdgbLc1qqT3kENNo/tKHOA1+TnPrZw7PY5wQR9xoXG1mzt+FuNY4 DvRTW+CAcVAtx3kgg6mWOSWwduNRGgca3FhGjZXoHvFu3it7/LSJncc+mnHZFg+FFdni FVTg== X-Gm-Message-State: APjAAAWp4vMa0XEax/263t0Uz6sLUv5Kif4HUuYOkQKc5cSX9xfNOD7v 5mAPbtryMBlS7JO5BCOkkKIm1sMPu+E= X-Google-Smtp-Source: APXvYqwE/E/Y7PUn3zcnGNBoOmjUnCDapV/wnSH53R1Qfb98x2zAnU56RgSLxkiLSYyEB+kLQtqe7A== X-Received: by 2002:a17:902:8609:: with SMTP id f9mr33006813plo.85.1553625828180; Tue, 26 Mar 2019 11:43:48 -0700 (PDT) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id r86sm30619660pfa.82.2019.03.26.11.43.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 26 Mar 2019 11:43:47 -0700 (PDT) Date: Tue, 26 Mar 2019 11:43:46 -0700 From: Matthias Kaehlcke To: Kyle Lin Cc: "Rafael J . Wysocki" , Viresh Kumar , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] cpufreq: stats: Use lock by stat to replace global spin lock Message-ID: <20190326184346.GY112750@google.com> References: <20190325072933.215946-1-linkyle0915@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190325072933.215946-1-linkyle0915@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 25, 2019 at 03:29:33PM +0800, Kyle Lin wrote: > Stats is updated by each policy, using the lock by stat can > reduce the contention. > > Signed-off-by: Kyle Lin > --- > drivers/cpufreq/cpufreq_stats.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c > index e2db5581489a..17beb1bc7e16 100644 > --- a/drivers/cpufreq/cpufreq_stats.c > +++ b/drivers/cpufreq/cpufreq_stats.c > @@ -14,7 +14,6 @@ > #include > #include > > -static DEFINE_SPINLOCK(cpufreq_stats_lock); > > struct cpufreq_stats { > unsigned int total_trans; > @@ -23,6 +22,7 @@ struct cpufreq_stats { > unsigned int state_num; > unsigned int last_index; > u64 *time_in_state; > + spinlock_t lock; /*spinlock for stats update*/ nit: not sure if the comment adds much value. If it stay there it needs a blank after '/*' and another before '*/' > unsigned int *freq_table; > unsigned int *trans_table; > }; > @@ -39,12 +39,12 @@ static void cpufreq_stats_clear_table(struct cpufreq_stats *stats) > { > unsigned int count = stats->max_state; > > - spin_lock(&cpufreq_stats_lock); > + spin_lock(&stats->lock); > memset(stats->time_in_state, 0, count * sizeof(u64)); > memset(stats->trans_table, 0, count * count * sizeof(int)); > stats->last_time = get_jiffies_64(); > stats->total_trans = 0; > - spin_unlock(&cpufreq_stats_lock); > + spin_unlock(&stats->lock); > } > > static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) > @@ -62,9 +62,9 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) > if (policy->fast_switch_enabled) > return 0; > > - spin_lock(&cpufreq_stats_lock); > + spin_lock(&stats->lock); > cpufreq_stats_update(stats); > - spin_unlock(&cpufreq_stats_lock); > + spin_unlock(&stats->lock); > > for (i = 0; i < stats->state_num; i++) { > len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i], > @@ -211,6 +211,7 @@ void cpufreq_stats_create_table(struct cpufreq_policy *policy) > stats->state_num = i; > stats->last_time = get_jiffies_64(); > stats->last_index = freq_table_get_index(stats, policy->cur); > + spin_lock_init(&stats->lock); > > policy->stats = stats; > ret = sysfs_create_group(&policy->kobj, &stats_attr_group); > @@ -242,11 +243,11 @@ void cpufreq_stats_record_transition(struct cpufreq_policy *policy, > if (old_index == -1 || new_index == -1 || old_index == new_index) > return; > > - spin_lock(&cpufreq_stats_lock); > + spin_lock(&stats->lock); > cpufreq_stats_update(stats); > > stats->last_index = new_index; > stats->trans_table[old_index * stats->max_state + new_index]++; > stats->total_trans++; > - spin_unlock(&cpufreq_stats_lock); > + spin_unlock(&stats->lock); > } Reviewed-by: Matthias Kaehlcke