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| author | Jocelyn Falempe <jocelyn.falempe@motorola.com> | 2010-03-11 14:01:11 -0800 |
|---|---|---|
| committer | Dave Jones <davej@redhat.com> | 2010-08-03 13:47:04 -0400 |
| commit | a665df9d510bfd5bac5664f436411f921471264a (patch) | |
| tree | 0814b40d3cf1974f0b6c9ad844d38d278fd0e458 /drivers/cpufreq/cpufreq_ondemand.c | |
| parent | 226528c6100e4191842e61997110c8ace40605f7 (diff) | |
| download | linux-3.10-a665df9d510bfd5bac5664f436411f921471264a.tar.gz linux-3.10-a665df9d510bfd5bac5664f436411f921471264a.tar.bz2 linux-3.10-a665df9d510bfd5bac5664f436411f921471264a.zip | |
[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>
Diffstat (limited to 'drivers/cpufreq/cpufreq_ondemand.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq_ondemand.c | 8 |
1 files 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); |