From: Len Brown <len.brown@intel.com>
To: davej@codemonkey.org.uk
Cc: alexey.y.starikovskiy@intel.com, cpufreq@lists.linux.org.uk
Subject: [PATCH 1/2 vs 2.6.18rc1] ondemand: tune for hardware coordination
Date: Thu, 13 Jul 2006 16:22:34 -0400 [thread overview]
Message-ID: <200607131622.34806.len.brown@intel.com> (raw)
From: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
cpufreq_ondemand.c | 16 ++++++++++------
1 files changed, 10 insertions(+), 6 deletions(-)
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@intel.com>
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Index: linux-2.6.15.1/drivers/cpufreq/cpufreq_ondemand.c
===================================================================
--- linux-2.6.15.1.orig/drivers/cpufreq/cpufreq_ondemand.c 2006-07-10 15:34:53.000000000 +0400
+++ linux-2.6.15.1/drivers/cpufreq/cpufreq_ondemand.c 2006-07-12 12:36:18.000000000 +0400
@@ -74,6 +74,7 @@
struct dbs_tuners {
unsigned int sampling_rate;
+ unsigned int sampling_rate_jiffies;
unsigned int up_threshold;
unsigned int ignore_nice;
};
@@ -139,6 +140,7 @@
}
dbs_tuners_ins.sampling_rate = input;
+ dbs_tuners_ins.sampling_rate_jiffies = usecs_to_jiffies(input);
mutex_unlock(&dbs_mutex);
return count;
@@ -303,26 +305,28 @@
{
unsigned int cpu = smp_processor_id();
struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
+ int delay = dbs_tuners_ins.sampling_rate_jiffies -
+ (jiffies % dbs_tuners_ins.sampling_rate_jiffies);
dbs_check_cpu(dbs_info);
- queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,
- usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
+ /* We want all CPUs to do sampling nearly on same jiffy */
+ 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);
+ int delay = dbs_tuners_ins.sampling_rate_jiffies -
+ (jiffies % dbs_tuners_ins.sampling_rate_jiffies);
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;
+ /* We want all CPUs to do sampling nearly on same jiffy */
+ queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
}
static inline void dbs_timer_exit(unsigned int cpu)
{
struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
-
cancel_rearming_delayed_workqueue(kondemand_wq, &dbs_info->work);
}
reply other threads:[~2006-07-13 20:22 UTC|newest]
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