[CPUFREQ] ondemand: don't synchronize sample rate unless multiple cpus present
For UP systems this is not required, and results in a more consistent
sample interval.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jocelyn Falempe <jocelyn.falempe@motorola.com>
Signed-off-by: Mike Chan <mike@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index fecfcdd..7b5093664 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -609,7 +609,9 @@
/* 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 @@
{
/* 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);