[CPUFREQ] ondemand: don't synchronize sample rate unless multiple cpu…

…s present For UP systems this is not required, and results in a more consistent sample interval. [[email protected]: coding-style fixes] Signed-off-by: Jocelyn Falempe <[email protected]> Signed-off-by: Mike Chan <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Dave Jones <[email protected]>
yshchan · Aug 3, 2010 · a665df9 · a665df9
1 parent 226528c
commit a665df9
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
@@ -609,7 +609,9 @@ static void do_dbs_timer(struct work_struct *work)
 	/* We want all CPUs to do sampling nearly on same jiffy */
 	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 
-	delay -= jiffies % delay;
+	if (num_online_cpus() > 1)
+		delay -= jiffies % delay;
+
 	mutex_lock(&dbs_info->timer_mutex);
 
 	/* Common NORMAL_SAMPLE setup */
@@ -634,7 +636,9 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
 {
 	/* We want all CPUs to do sampling nearly on same jiffy */
 	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
-	delay -= jiffies % delay;
+
+	if (num_online_cpus() > 1)
+		delay -= jiffies % delay;
 
 	dbs_info->sample_type = DBS_NORMAL_SAMPLE;
 	INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);