Hi,
The ondemand delay value is calculated before calling dbs_check_cpu which can lead to a delay value of sampling_rate*sampling_down_factor but a frequency set to the lowest value. The main result is a slow responsiveness during this period. This patch moves the calculation of delay after the call of dbs_check_cpu. I have seen this problem when testing cpufreq-bench on my Arm platform.
Vincent
On 7 February 2011 17:14, Vincent Guittot vincent.guittot@linaro.org wrote:
calculate ondemand delay after dbs_check_cpu call because it can modify rate_mult value
use freq_lo_jiffies value for the sub sample period of powersave_bias mode
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org
drivers/cpufreq/cpufreq_ondemand.c | 20 +++++++++++++------- 1 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 58aa85e..44c2dba 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -641,13 +641,7 @@ static void do_dbs_timer(struct work_struct *work) container_of(work, struct cpu_dbs_info_s, work.work); unsigned int cpu = dbs_info->cpu; int sample_type = dbs_info->sample_type;
- /* We want all CPUs to do sampling nearly on same jiffy */
- int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate
- * dbs_info->rate_mult);
- if (num_online_cpus() > 1)
- delay -= jiffies % delay;
- int delay;
mutex_lock(&dbs_info->timer_mutex);
@@ -660,10 +654,22 @@ static void do_dbs_timer(struct work_struct *work) /* Setup timer for SUB_SAMPLE */ dbs_info->sample_type = DBS_SUB_SAMPLE; delay = dbs_info->freq_hi_jiffies;
- } else {
- /* We want all CPUs to do sampling nearly on
- * same jiffy
- */
- delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate
- * dbs_info->rate_mult);
- if (num_online_cpus() > 1)
- delay -= jiffies % delay;
}
} else { __cpufreq_driver_target(dbs_info->cur_policy, dbs_info->freq_lo, CPUFREQ_RELATION_H);
- delay = dbs_info->freq_lo_jiffies;
} schedule_delayed_work_on(cpu, &dbs_info->work, delay); mutex_unlock(&dbs_info->timer_mutex); -- 1.7.1