[Canonical-tech] Final set of results from the Power Management Blueprint

Colin Ian King colin.king at canonical.com
Thu Mar 29 14:32:58 UTC 2012

On 28/03/12 17:09, Mark Shuttleworth wrote:
> On 28/03/12 14:46, Colin Ian King wrote:
>> Now beta2 is nearly here I ran some (very simple) tests last night and
>> this morning on Unity 2D vs 3D to see how they compare in terms of
>> power consumption on a HP Mini 210 (Atom N450) and a Lenovo X220i
>> (Sandybridge, i3).
> Awesome work, Colin. Thank you! Both for the reporting and the
> improvements in 12.04.
> Should we be worried about the 100mA idle delta between 2D and 3D on the
> Lenovo?

I've dug into this by comparing wakeup events and process activity over 
100 seconds of idle time for 2D vs 3D.  The only easily noticeable 
difference between 2D and 3D in this respect is that 3D has compiz 
running and it wakes up ~2-3 times a second on average. The CPU 
utilisation for this is very small though, ~0.03%, so I am supposing 
there may be some GPU activity going on too which may consume some 
power. I'm not sure how easy it would be to verify this.

Also, Xorg in 3D seems to be using a very small amount more CPU in 3D 
compared to 2D so that may account for a small part of the 100mA.

Apart from that, I'm finding it hard to account as there is quite a bit 
of 'noise' in the data I've captured which affects the final analysis.


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