From a665df9d510bfd5bac5664f436411f921471264a Mon Sep 17 00:00:00 2001 From: Jocelyn Falempe Date: Thu, 11 Mar 2010 14:01:11 -0800 Subject: [PATCH] [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 --- drivers/cpufreq/cpufreq_ondemand.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index fecfcdda6dd..7b5093664e4 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); -- 2.20.1