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#1 2010-02-06 13:40:44

Natanji
Member
Registered: 2009-09-22
Posts: 133

Can't get rid of my high power consumption (Thinkpad X60 Tablet)

This is really driving me nuts. On Windows 7, I can achieve a power consumption of around 11-12W (with moderate web surfing usage over WLAN and full screen brightness, just Aero turned off).
On Arch, I can't get below 13W *ever* with full screen brightness, even without WLAN and any kind of computer usage besides running X11. And normal moderate web surfing usage (without Flash, mind you) brings it up to at least 17W.

The reason for this, I believe, is a really high number of wakeups from idle. powertop shows me at least 40 wakeups per second even when I don't have anything running besides X11. If I have Firefox, Thunderbird and Pidgin running, this climbss to at least 80 wakeups per second. Powertop shows the main cause for the wakeups in both cases to be "acpi" and "extra timer interrupt", as well as "Reschedulin interrupts". With those three applications running, there is additionally a high usage of "hrtimer_start_range_ns (tick_sched_timer)" and "iwl3945" (well, I guess the latter figures for internet applications).

I'm running laptop-mode-tools for power management, btw.

Anyone got some idea of what causes those idle wakeups, and how I might be able to fix it? I don't see why Windows 7 should be better than Arch here, the bloated monstrum it is...

Last edited by Natanji (2010-02-06 13:40:58)

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#2 2010-02-11 20:42:54

Natanji
Member
Registered: 2009-09-22
Posts: 133

Re: Can't get rid of my high power consumption (Thinkpad X60 Tablet)

*bump*

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#3 2010-02-11 20:53:41

Urfaust
Member
From: Germany
Registered: 2009-01-30
Posts: 164

Re: Can't get rid of my high power consumption (Thinkpad X60 Tablet)

The issue with hrtimer_start_range_ns is existing for a while. Unfortunately it isn't fixed until today. There is an entry in the kernel bugtracker http://bugzilla.kernel.org/show_bug.cgi?id=14424
I think this is the main reason for the short battery life of my Samsung NC10 sad. If you google for it you will find numerous posting in bugtrackers of various distributions but no one seems to really care or know how to fix this?

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#4 2010-03-02 09:42:05

Natanji
Member
Registered: 2009-09-22
Posts: 133

Re: Can't get rid of my high power consumption (Thinkpad X60 Tablet)

Wow, after the current kernel update my power usage rose again. I'm at > 300 wakeups per second now with only X running (no programs), which uses 20W in idle (!). This is really crazy...

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