[Power] FW: OLPC Power Log

[Richard A. Smith]

On 01/08/2013 06:01 PM, Kishwer.Aziz wrote:

> Richard,
>
> this is much delayed but finally after much chasing I have been sent
> these power logs. Remember me I ma from Rahnuma School in Pakistan and
> our batteries run out after 3 hours. I am told children are reading
> without the backlight but the batteries still run out in the same sort
> of time. I am sure you will be able to find out more from the power logs.

I'm cc:ing the support gang list since many people there may be 
interested as well.  I've also bcc:ed the power at l.o list for archival 
and searching.  Its a bcc because I wan't to avoid all the bounced 
messages from SG members who may respond that are not members of the 
power@ list.  I'll follow up with a summaries to the power@ list when 
necessary.

My first observation is that you are using a really, really, old version 
of the os.  You are using release 10.1.2 which was released in August of 
2010.  Is there a specific reason you have never upgraded?

I recommend that you try to chart out an upgrade path ASAP. There are 
both kernel and powerd bugs that make analysis of your existing power 
logs difficult.  Its also going to be hard for me to invest a lot of 
time in diagnosing what your problem is on a build thats over 2 years 
old.  So many bugs and changes have been made since then.

I realize that field upgrades can be disruptive to your environment and 
that the Sugar interface had changed a lot in later releases.  At 
minimum you need to upgrade to 10.1.3 so I know the kernel and powerd 
bugs are fixed.

Bugs non-withstanding I was able to extract power info from your powerd 
logs.  Please review the following graph.  This is not from all your 
logs, just enough that I got the general idea.

http://dev.laptop.org/~rsmith/kishwer.pdf

I see 2 interesting things:

1) A large number of your logs show that the machine was booted up, 
used, and then shutdown in under half an hour.  Is that expected?  If 
its not expected then we need to investigate and see if the kernel 
timestamp bug is messing up the log files.  (Again. please upgrade)

2) You have numerous runs that show your system averaging a power draw 
of 8 watts or more for extended periods.  This is very unexpected unless 
you were doing something like running the camera.  Especially if the 
backlight is off.  The logs I have from our test group in New Zealand 
have average in the 4-6 watt range with only an occasional blip into the 
8W or greater range.  This means that something is sitting there keeping 
the cpu busy and chewing up battery.  Its also going to prevent you from 
suspending.

You mentioned that the primary use of these machines was as e-readers. 
I would not expect the reading activity to be using so much cpu. Can you 
please provide more information on exactly what the kids are doing and 
what activities they are using?

Thanks.

-- 
Richard A. Smith  <richard at laptop.org>
One Laptop per Child