Linux vs. linux-ck power usage - laptop users please post your results

Question

Krum reported are rather significant increase in power consumption when using the linux-ck kernel vs. the linux (stock ARCH) kernel.
krum wrote:With the last ck i7-avx, I jump from 10W (stock arch) to 15W on my laptop with the same kernel options and same usage.
I will investigate further another time...
I began to wonder just how universal this was so I tested on my own laptop (Intel T9400 @ 2.53 GHz, NVidia FX, 2x2 GB, SSD and 17" screen) booted into three different kernels, ARCH, ck-generic, and ck-core2 with the latter two downloaded from my unofficial repo.  I took two readings per kernel.  The first was measured with powertop on battery after letting it settle for a good 3 min of idle.  The second was with the battery removed and on AC power measured with a Kill-A-Watt.  My results indicate no significant differences.
linux-3.0.3-1
Powertop: 37.5
Kitt-A-Watt: 41
linux-ck-3.0.3-4
Powertop: 38.6
Kitt-A-Watt: 41
linux-ck-core2-3.0.3-4
Powertop: 37.5
Kitt-A-Watt: 40
Can others running both kernels do a similar analysis with powertop and post the results here?

Answer 1

Hi,
I did my test with powertop.
I got also higher temp:
[root@akira david]# uname -a && uptime && fan
Linux akira 3.0-ck #1 SMP PREEMPT Sun Aug 21 05:31:12 EDT 2011 x86_64 Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz GenuineIntel GNU/Linux
22:20:24 up 10:26,  4 users,  load average: 0.00, 0.03, 0.07
speed:        2616
level:        auto
Core 0:         +47.0°C 
Core 1:         +42.0°C
[root@akira david]# uname -a && uptime && fan
Linux akira 3.0-ARCH #1 SMP PREEMPT Wed Aug 17 21:55:57 CEST 2011 x86_64 Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz GenuineIntel GNU/Linux
22:22:52 up 2 min,  4 users,  load average: 0.28, 0.19, 0.08
speed:        2630
level:        auto
Core 0:         +39.0°C 
Core 1:         +38.0°C
EDIT:
[root@akira david]# uname -a && uptime && fan
Linux akira 3.0-ck #1 SMP PREEMPT Sun Aug 21 05:31:12 EDT 2011 x86_64 Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz GenuineIntel GNU/Linux
22:29:41 up 2 min,  4 users,  load average: 0.18, 0.24, 0.10
speed:        2644
level:        auto
Core 0:         +40.0°C 
Core 1:         +35.0°C
My bad, I forget to had these kernel boot option: pcie_aspm=force i915.i915_enable_rc6=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1
So it seems to be OK, I will do new powertop test when my battery will be full.
Last edited by krum (2011-08-28 21:11:47)