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#1 2009-07-31 04:15:00

drostin77
Member
Registered: 2009-07-15
Posts: 45

Tickless Idle: Enabled by default?

Running arch on 1000HE.  kernel 2.6.30.

I have read many places I should use a "tickless idle" to extend battery life.  I cannot seem to find how to do this.  Is the tickless idle simply enabled in kernels > 2.6.24, or do I need to enable it / compile it?  If it requires enabling how do I a) check if its enabled and b) enable it?

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#2 2009-07-31 07:07:43

brebs
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Registered: 2007-04-03
Posts: 3,742

Re: Tickless Idle: Enabled by default?

zgrep NO_HZ /proc/config.gz

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#3 2009-07-31 07:14:59

Wintervenom
Member
Registered: 2008-08-20
Posts: 1,011

Re: Tickless Idle: Enabled by default?

It is enabled by default in the stock kernel.  Note that it may cause problems on some machines.

Last edited by Wintervenom (2009-08-07 07:11:35)

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#4 2009-07-31 12:20:32

scio
Member
From: Buffalo, NY
Registered: 2008-08-05
Posts: 366

Re: Tickless Idle: Enabled by default?

Be sure to use:
http://aur.archlinux.org/packages.php?ID=27705
http://aur.archlinux.org/packages.php?ID=23318

Those will be the best way to save battery along by under-clocking and disabling peripherals you aren't using (wifi is HUGE power draw).

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#5 2009-08-07 00:41:35

drostin77
Member
Registered: 2009-07-15
Posts: 45

Re: Tickless Idle: Enabled by default?

Thanks for the replies all:)  And sorry for my slow one. 

breb:

bash-4.0$ zgrep NO_HZ /proc/config.gz
CONFIG_NO_HZ=y

Is that what it should return if enabled?

scio:

I'm using those 2, thanks.  Still getting rather sub-par (~6 hours) battery life.  I suspect (as you hint) its wifi's fault because even when I rfkill my wifi and its gone from /sys/class/net the LED on my eee indicates the wifi is still on...

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#6 2009-08-07 03:13:19

iphitus
Forum Fellow
From: Melbourne, Australia
Registered: 2004-10-09
Posts: 4,927

Re: Tickless Idle: Enabled by default?

I've got a 1000HE and I can get 7-9 hours, depending entirely on usage.

Here's a few tips:

* Install laptop-mode-tools.
* Add eeepc-laptop to your /etc/rc.conf MODULES line
* Install laptop-mode-tools-superhe, this makes a significant difference
* Configure /etc/laptop-mode/laptop-mode.conf
* Enable the following configurations in /etc/laptop-mode/conf.d/
cpufreq, usb-autosuspend, hal-polling, bluetooth, intel-sata-powermgmt, intel-hda-powersave

* Ensure you configure cpufreq especially, it can help a great deal. The ondemand governer works perfectly.
* If you use audio often, you might want to extend the sleep time or disable intel-hda-powersave, as it makes a sound on my system whenever the card wakes up from sleep.
* Enable lcd-brightness, use the following, adjust the backlight levels to your preference

BATT_BRIGHTNESS_COMMAND="echo 3"
LM_AC_BRIGHTNESS_COMMAND="echo 15"
NOLM_AC_BRIGHTNESS_COMMAND="echo 15"
BRIGHTNESS_OUTPUT="/sys/devices/virtual/backlight/eeepc/brightness"

* On my laptop at least, the wireless-led at the front doesn't appear to actually reflect whether the card is active or not

* If your 1000HE has the rt2860sta wireless device, you can use the following command to run it at low power

iwpriv ra0 set PSMode=MAX_PSP

If it's not the rt2860sta, try messing about with 'iwconfig power' - read the iwconfig manpage.

* Don't leave gmail or other similar ajax heavy websites open - these shorten battery life nicely by continually waking the system and continually using wireless.
* I find midori/arora/uzbl a bit lighter on the system than firefox, though this is subjective.
* Install powertop. It can be very useful for finding applications which are continually waking the system up and keeping it out of power saving modes. Some misbehaving apps include xbindkeys and dropbox. Most browsers are pretty miserable so close them when not in use.
* Ensure the internal-sd card reader is disabled
* Unload uhci-hcd/ehci-hcd when you're not using USB.

Some of the above are pretty small gains, but they add up. Others like cpufreq, superhe, laptop-mode, lcd-backlight make a significant difference. Others simply aren't practical sometimes, so just use what makes sense.

At the moment with wifi on and firefox, i'm getting just over 8 hours. Powertop is reporting 7.9W power usage. Without wifi it goes down to 6.9W.

Hope that helps somewhat.

James

Last edited by iphitus (2009-08-07 03:16:01)

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#7 2009-08-07 04:20:52

drostin77
Member
Registered: 2009-07-15
Posts: 45

Re: Tickless Idle: Enabled by default?

iphitus:

  Thanks much for the reply!  Questions are bolded here since I tend to ramble so if you wanna skip the rambling parts...

  As for your list, I've done (almost) all of those things, though to be honest I am not sure how to actually check if most of them are working.

  I know laptop-mode-tools-superhe works (forgot which file but cat /something/or/other returned a good value).

  I am using rt2860sta, so I will set it to Maximum Power Save Party-style (MAX_PSP, just guessing acronyms).

  Thanks also for posting your powertop "score" (heheh, fine, "watts").  I was hoping to find out what was good/normal for this.

  As suspected me EEE is running a bit high (8.2 no wireless, astronomical (11.3) with a 3.5 wireless dongle ;p).

  Can I ask, when nothing but an urxvt (or xterm or whatever) and your window manager are running approximately how many wakeups per second you are getting?

  I have been using powertop quite a bit to try to track things down, I have noticed that firefox was certainly a problem.  However, I was wondering about the following entry, which is almost always the most wakeups by a considerable margin, here's the culprit:

  hrtime_start_range_ns (tick_sched_timer)

What is this process doing?  Does this mean I am /not/ running tickless? Or, since its scheduling ticks dynamically perhaps it means I /am/ running tickless and I'm stuck with this thing.

* Ensure the internal-sd card reader is disabled
* Unload uhci-hcd/ehci-hcd when you're not using USB.

How do I do these two things / confirm they are done ?

  On average how much power do you "bleed" when suspended? I seem to bleed rather more battery life than I would expect to, but as my tuxonice is still giving me problems (been busy recently and I need to shrink my partition to give tuxonice a li'l swap, but come this weekend tuxonice better watch out, its gna be working so smooth it cries) I have no hibernate for now.

How can I confirm that cpufreq is working?  (Or any of the other utilities I have enabled in /etc/laptop-mode/conf.d/... I can guess my HD is working (light only turns on every 10 minutes to say hd is busy), but usb-autosuspend, hal-polling (this one especially is "abstract" to me), bluetooth, and cpufreq I'm not sure how to check)

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#8 2009-08-07 04:54:28

iphitus
Forum Fellow
From: Melbourne, Australia
Registered: 2004-10-09
Posts: 4,927

Re: Tickless Idle: Enabled by default?

Term is xterm, though urxvt should be fine.  WM is echinus.

hrtime_start_range_ns (tick_sched_timer)

Don't worry about this so much, unless it's something astronomical

* Ensure the internal-sd card reader is disabled
    * Unload uhci-hcd/ehci-hcd when you're not using USB.

If you have the eeepc-laptop kernel module loaded

echo 0 > /sys/bus/platform/devices/eeepc/cardr

To check it worked, just read that same file and ensure it is 0. To enable, echo 1 instead.

To unload the ehci-hcd/uhci-hcd kernel modules, "rmmod" them. Keep in mind, they're the USB drivers, so without these, no USB. I don't think the savings from these are much anyway.

On average how much power do you "bleed" when suspended?

No idea, I've never checked. I usually just suspend to disk with the standard suspend to disk - not tuxonice.

How can I confirm that cpufreq is working?

Install cpufrequtils and have a look at the output of cpufreq-info

As for checking the others, if you enabled them, they should be working. Even if they're not, they dont make as big a difference.

Also for the wifi, you might find MAX_PSP.... slow. So there's also FAST_PSP which is about medium. Same command except swap MAX_PSP with FAST_PSP

Last edited by iphitus (2009-08-07 04:59:24)

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