The patch titled
cpufreq: ondemand: don't synchronize sample rate unless mulitple cpus present
has been added to the -mm tree. Its filename is
cpufreq-ondemand-dont-synchronize-sample-rate-unless-mulitple-cpus-present.patch
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------------------------------------------------------
Subject: cpufreq: ondemand: don't synchronize sample rate unless mulitple cpus present
From: Jocelyn Falempe <jocelyn.falempe@xxxxxxxxxxxx>
For UP systems this is not required, and results in a more consistent
sample interval.
Signed-off-by: Jocelyn Falempe <jocelyn.falempe@xxxxxxxxxxxx>
Signed-off-by: Mike Chan <mike@xxxxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/cpufreq/cpufreq_ondemand.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN drivers/cpufreq/cpufreq_ondemand.c~cpufreq-ondemand-dont-synchronize-sample-rate-unless-mulitple-cpus-present drivers/cpufreq/cpufreq_ondemand.c
--- a/drivers/cpufreq/cpufreq_ondemand.c~cpufreq-ondemand-dont-synchronize-sample-rate-unless-mulitple-cpus-present
+++ a/drivers/cpufreq/cpufreq_ondemand.c
@@ -579,7 +579,9 @@ static void do_dbs_timer(struct work_str
/* 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 */
@@ -604,7 +606,9 @@ static inline void dbs_timer_init(struct
{
/* 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);
_
Patches currently in -mm which might be from jocelyn.falempe@xxxxxxxxxxxx are
cpufreq-ondemand-dont-synchronize-sample-rate-unless-mulitple-cpus-present.patch
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