From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: [PATCH 1/2 vs 2.6.18rc1] ondemand: tune for hardware coordination Date: Thu, 13 Jul 2006 16:22:34 -0400 Message-ID: <200607131622.34806.len.brown@intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org+glkc-cpufreq=m.gmane.org@lists.linux.org.uk Content-Type: text/plain; charset="us-ascii" To: davej@codemonkey.org.uk Cc: alexey.y.starikovskiy@intel.com, cpufreq@lists.linux.org.uk From: Venkatesh Pallipadi 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 Signed-off-by: Alexey Starikovskiy Signed-off-by: Len Brown 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); }