From 1ce28d6b19112a7c76af8e971e2de3109d19a943 Mon Sep 17 00:00:00 2001
From: Alexey Starikovskiy <alexey_y_starikovskiy@linux.intel.com>
Date: Mon, 31 Jul 2006 22:25:20 +0400
Subject: [PATCH] [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>
---
drivers/cpufreq/cpufreq_ondemand.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 52cf1f021825..f507a869acbc 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -305,6 +305,9 @@ static void do_dbs_timer(void *data)
{
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 @@ static void do_dbs_timer(void *data)
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)
--
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