[CPUFREQ][1/2] ondemand: updated tune for hardware coordination
Try to make dbs_check_cpu() call on all CPUs at the same jiffy.
This will help when multiple cores share P-states via Hardware Coordination.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi at intel.com>
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy at intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 52cf1f0..f507a86 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -305,6 +305,9 @@
{
unsigned int cpu = smp_processor_id();
struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
+ /* 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 (!dbs_info->enable)
return;
@@ -312,18 +315,18 @@
lock_cpu_hotplug();
dbs_check_cpu(dbs_info);
unlock_cpu_hotplug();
- queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,
- usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
+ queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
}
static inline void dbs_timer_init(unsigned int cpu)
{
struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
+ /* We want all CPUs to do sampling nearly on same jiffy */
+ int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
+ delay -= jiffies % delay;
INIT_WORK(&dbs_info->work, do_dbs_timer, 0);
- queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,
- usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
- return;
+ queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
}
static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)