Thread (14 messages) 14 messages, 3 authors, 2013-02-05

Re: [PATCH 2/3] PM / devfreq: fix stats start time stamp

From: MyungJoo Ham <myungjoo.ham@samsung.com>
Date: 2013-01-14 14:42:17
Also in: lkml

On Tue, Jan 8, 2013 at 2:50 PM, Rajagopal Venkat
[off-list ref] wrote:
Mark the stats start time stamp when actual load monitoring is
started for accuracy.
It appears that you are changing the semantics of the information here.


For example, in the case:
- devfreq started at 0 w/ 100MHz
- at 10, devfreq monitor starts w/ 100MHz
- at 20, devfreq updates the freq to 200MHz
- at 30, devfreq is requested to show the stat

The conventional:
20 @ 100MHz / 10 @ 200MHz

You proposed:
10 @ 100MHz / 10 @ 200MHz


Could you please give some reasons why the latter is "more accurate"?
To me, the former seems appropriate.



Cheers,
MyungJoo

quoted hunk ↗ jump to hunk
Signed-off-by: Rajagopal Venkat <redacted>
---
 drivers/devfreq/devfreq.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 5782c9b..2843a22 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -254,9 +254,12 @@ static void devfreq_monitor(struct work_struct *work)
 void devfreq_monitor_start(struct devfreq *devfreq)
 {
        INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
-       if (devfreq->profile->polling_ms)
+       if (devfreq->profile->polling_ms) {
                queue_delayed_work(devfreq_wq, &devfreq->work,
                        msecs_to_jiffies(devfreq->profile->polling_ms));
+
+               devfreq->last_stat_updated = jiffies;
+       }
 }
 EXPORT_SYMBOL(devfreq_monitor_start);
@@ -498,7 +501,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
        devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
                                                devfreq->profile->max_state,
                                                GFP_KERNEL);
-       devfreq->last_stat_updated = jiffies;
        devfreq_set_freq_limits(devfreq);

        dev_set_name(&devfreq->dev, dev_name(dev));
--
1.7.10.4

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-- 
MyungJoo Ham, Ph.D.
Mobile Software Platform Lab, DMC Business, Samsung Electronics
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