From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Kaehlcke Subject: Re: [PATCH] cpufreq: stats: Use lock by stat to replace global spin lock Date: Tue, 26 Mar 2019 11:43:46 -0700 Message-ID: <20190326184346.GY112750@google.com> References: <20190325072933.215946-1-linkyle0915@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20190325072933.215946-1-linkyle0915@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Kyle Lin Cc: "Rafael J . Wysocki" , Viresh Kumar , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-pm@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