From: Jocelyn Falempe Date: Thu, 11 Mar 2010 22:01:11 +0000 (-0800) Subject: [CPUFREQ] ondemand: don't synchronize sample rate unless multiple cpus present X-Git-Tag: v2.6.36-rc1~578^2~10 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a665df9d510bfd5bac5664f436411f921471264a;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git [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 Signed-off-by: Mike Chan Signed-off-by: Andrew Morton Signed-off-by: Dave Jones --- diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index fecfcdd..7b50936 100644 --- 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);