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#1 2011-09-05 11:18:42

jacopo_c
Member
From: Italy
Registered: 2009-04-29
Posts: 6

[SOLVED] Huge power consumption after kernel upgrade.

Dear All,

I have recently bought the new lenovo thinkpad X1 equipped with a Core I5 processors and 4GB of RAM.
I am quite satisfied with this machine except for the fact that the fan is extremely loud (but perhaps a bios upgrade will fix problem).

Now my problem:
When I first installed Arch (first days of August) I ran powertop and the power consumption was around 10 Watts when idle with wifi card turned off.
Now, after some upgrades, the power consumption raises to 18W in idle and consequently the battery lasts less than 2h.

Here my current configuration:

Linux think-x1 3.0-ARCH #1 SMP PREEMPT Tue Aug 30 08:53:25 CEST 2011 x86_64 Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz GenuineIntel GNU/Linux

and here the powertop output obtained with the cpu frequency governor set to "On demand":

Cn                Avg residency       P-states (frequencies)
C0 (cpu running)        ( 5.3%)       Turbo Mode     0.1%
polling           0.0ms ( 0.0%)         2.50 Ghz     0.0%
C1 mwait          0.2ms ( 0.1%)         2.21 Ghz     0.0%
C2 mwait          0.3ms ( 0.0%)         1200 Mhz     0.1%
C3 mwait          2.4ms ( 0.0%)          800 Mhz    99.8%
C4 mwait         13.1ms (94.6%)
Wakeups-from-idle per second : 76.1     interval: 3.0s
Power usage (ACPI estimate): 15.7W (2.8 hours)

Top causes for wakeups:
  46.5% (135.7)   kworker/0:0
  17.7% ( 51.7)   PS/2 keyboard/mouse/touchpad interrupt
  11.9% ( 34.7)   [kernel scheduler] Load balancing tick
   8.6% ( 25.0)   [iwlagn] <interrupt>
   2.9% (  8.3)   [i915] <interrupt>
   2.6% (  7.7)   [acpi] <interrupt>
   1.8% (  5.3)   chromium
   1.6% (  4.7)   [kernel core] hrtimer_start (tick_sched_timer)
   1.5% (  4.3)   kworker/0:1
   0.7% (  2.0)   minilogd
   0.7% (  2.0)   [kernel core] iwl_bg_watchdog (iwl_bg_watchdog)
   0.6% (  1.7)   X
   0.6% (  1.7)   [kernel core] intel_gpu_idle_timer (intel_gpu_idle_timer)
   0.3% (  1.0)   Terminal
   0.3% (  1.0)   [kernel core] tpt_trig_timer (tpt_trig_timer)
   0.2% (  0.7)   [mmc0, mei, ehci_hcd:usb3] <interrupt>
   0.2% (  0.7)   upowerd
   0.1% (  0.3)   init
   0.1% (  0.3)   gpg-agent
   0.1% (  0.3)   [kernel core] ieee80211_sta_reset_conn_monitor (ieee80211_sta_conn_mon_timer)
   0.1% (  0.3)   wicd-client
   0.1% (  0.3)   kworker/u:3
   0.1% (  0.3)   watchdog/0

I have also tried to disable most of the running daemons and unload some modules, but I have never got less than 14/15W when idle, which in my opinion is definitely too much!

As far as I'm concerned, the kworker process is responsible most of the wakeups. 

Any ideas?

Last edited by jacopo_c (2011-09-05 13:12:16)

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#2 2011-09-05 11:29:31

Woofie
Member
From: RK, Czech Rep.
Registered: 2009-12-28
Posts: 83

Re: [SOLVED] Huge power consumption after kernel upgrade.

Hi it's look like kernel related problem. You sholud look at this info at Phronix.


Sorry for my english. It's not my native language..

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#3 2011-09-05 12:21:12

jac
Member
From: /home/jac
Registered: 2009-05-19
Posts: 431
Website

Re: [SOLVED] Huge power consumption after kernel upgrade.

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#4 2011-09-05 12:54:48

einhard
Member
From: Poland
Registered: 2010-01-05
Posts: 89

Re: [SOLVED] Huge power consumption after kernel upgrade.

Try adding

pcie_aspm=force i915.i915_enable_rc6=1

to the kernel line in your bootloader config file.

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#5 2011-09-05 13:08:15

jacopo_c
Member
From: Italy
Registered: 2009-04-29
Posts: 6

Re: [SOLVED] Huge power consumption after kernel upgrade.

Great! By adding

pcie_aspm=force i915.i915_enable_rc6=1

to the kernel boot parameters, the power consumption when idle dropped to 10 W!

Thank you very much

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#6 2011-09-05 23:24:54

pogeymanz
Member
Registered: 2008-03-11
Posts: 1,020

Re: [SOLVED] Huge power consumption after kernel upgrade.

Based on the stuff at Phoronix, it seems like the i915.i915_enable_rc6=1 options makes for less power usage when idle, but more when it's actually in use. How often do you just sit with your laptop idle in your lap?

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#7 2011-09-06 12:55:53

stqn
Member
Registered: 2010-03-19
Posts: 1,189
Website

Re: [SOLVED] Huge power consumption after kernel upgrade.

If you read web pages, quite often I'd say smile.

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#8 2011-09-08 02:46:38

pogeymanz
Member
Registered: 2008-03-11
Posts: 1,020

Re: [SOLVED] Huge power consumption after kernel upgrade.

Fair enough.

My power usage is still higher than it was with 2.6.39 even with all these boot parameters. I'm really upset at all the regression I've experienced and read about in the kernel since around 2.6.35.

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#9 2011-09-08 05:44:04

the sad clown
Member
From: 192.168.0.X
Registered: 2011-03-20
Posts: 833

Re: [SOLVED] Huge power consumption after kernel upgrade.

I just wanted to thank you for posting this solution.  I noticed an almost immediate drop in core temp of 10c upon implementing this.  It was always bugging me why it insisted on hanging around 50c and now I've seen it get down to 37c for probably the first time.


I laugh, yet the joke is on me

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#10 2011-09-09 08:38:11

jacopo_c
Member
From: Italy
Registered: 2009-04-29
Posts: 6

Re: [SOLVED] Huge power consumption after kernel upgrade.

I haven't had much experience with the 2.6.39 kernel, but after adding those options the power consumption dropped to 10 Watts with wifi-on and light use, which seems quite low especially with respect to my previous laptop (Core2Duo@2.2GHz) (in that case power consumption was around 15W).

Core temperature with wifi and light use stays around 47 °C, whilst the temperature in the room is 28°C.

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#11 2011-09-09 17:55:55

tab1293
Member
Registered: 2011-08-31
Posts: 7

Re: [SOLVED] Huge power consumption after kernel upgrade.

Can confirm this helps lower power consumption on the Thinkpad T420. I am wondering though does this boot parameter sacrifice any performance? Also when are we going to see a fix for this power regression issue? 3.1?

Last edited by tab1293 (2011-09-09 17:56:11)

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#12 2011-09-09 19:55:18

jaco
Member
From: Toulouse, France
Registered: 2011-03-17
Posts: 149

Re: [SOLVED] Huge power consumption after kernel upgrade.

For my own (HP Probook with I5 Sandy-bridge without concrete GPU), these parameters do the job... Instead of 65-68°C, i have now 55-58°C and i've not noticed any performance penalty.

I don't use laptop mode, nor any specific laptop optimization as i'm never in battery mode.

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#13 2011-09-10 14:47:37

pogeymanz
Member
Registered: 2008-03-11
Posts: 1,020

Re: [SOLVED] Huge power consumption after kernel upgrade.

tab1293 wrote:

Can confirm this helps lower power consumption on the Thinkpad T420. I am wondering though does this boot parameter sacrifice any performance? Also when are we going to see a fix for this power regression issue? 3.1?

I read somewhere that the kernel devs really don't see this as an issue. They just expect that laptop owners should know to try these boot parameters. So, definitely not by 3.1.

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#14 2011-09-12 00:22:42

masteryod
Member
Registered: 2010-05-19
Posts: 429

Re: [SOLVED] Huge power consumption after kernel upgrade.

pogeymanz wrote:

I read somewhere that the kernel devs really don't see this as an issue. They just expect that laptop owners should know to try these boot parameters. So, definitely not by 3.1.

from https://bugzilla.redhat.com/show_bug.cgi?id=727579:

Dave Jones 2011-08-03 15:32:21 EDT

enabling it by default in 3.0 caused regressions for some people, so it was
disabled. Hopefully Intel figures it out, and we can switch it back on by
default in 3.1 / 2.6.41 (until then, you'll have to set it by hand).

Interesting stuff, also recommend this thread on phoronix:
http://phoronix.com/forums/showthread.p … Regression

Last edited by masteryod (2011-09-12 00:30:00)

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