Powertop and powersaving tips?

[DupermanDave]

I've been scouring the web for powersaving tips and I just can't seem to apply any of the methods I'm learning. I've been using linux since Red Hat 5.0 and have mainly been using it on laptops and it has never been good with battery life. On this Windows 7 machine I can stretch out my battery life to about 9 hours. On linux I can't seem to break an hour and 15. Right now my battery monitor flip flops from 2 hours 22 minutes to an hour and 10 minutes.

I've used powertop before on OpenSuSE, but that was an odd interactive mode. I'd run powerop as root and it was systematically analyze my system and ask me to disable features. That seemed to work quite well. Now, with the newer powertops, it just looks like the top interface with power consumption info. I can't seem to figure out how to disable stuff that's waking up other processes and eating up my CPU cycles.

ANy advice would be greatly appreciated. I have one more question. I have a dual graphics card setup (intel and ATI) and I feel the ATI card may be in use by default. Anyone know how I can see which card is being used and how I can turn it off completely and use the intel card?

[glennzo]

Powertop is something that I've just started looking at over the last weekend so I'm by no means an authority on the subject, but I can give you the links I've been exploring.

http://docs.fedoraproject.org/en-US/.../PowerTOP.html
https://lesswatts.org/projects/powertop/
https://01.org/powertop/

I haven't made too much progress with the subject computer. I've only disabled the unused audio device to date.

[DupermanDave]

Originally Posted by glennzo

Powertop is something that I've just started looking at over the last weekend so I'm by no means an authority on the subject, but I can give you the links I've been exploring.

http://docs.fedoraproject.org/en-US/.../PowerTOP.html
https://lesswatts.org/projects/powertop/
https://01.org/powertop/

I haven't made too much progress with the subject computer. I've only disabled the unused audio device to date.

That first link is great, but as with all of the documentation and videos I'm finding, the instructions are incomplete. I just finished a second round of "powertop --calibrate" and I'm sitting at the turntables menu where the guide says, "The enter key toggles the suggestion on and off. " In application, not really. It toggles the setting as "good" or "bad". What's good and what's bad? How does one finalize and apply these settings?

The documentation also says, "The Tunables tab contains suggestions for optimizing the system for lower power consumption." Again, it does not. It lists a bunch of hardware and has a good/bad status on it. There's no mentioning of a suggested command to run to fix the power drain.

[smr54]

Dimming screen brightness, if you don't need it, is one of the quickest ways to add an hour or two to battery life. There's some power saving tips on the Arch Wiki.
https://wiki.archlinux.org/index.php...wer_Management

EDIT--Arch Linux's powertop will also give suggestions about tunables, such as the ones that you mention are missing. I've only used it in package form from both Fedora and Arch. In Fedora's case, good should mean that it's saving power.

[glennzo]

This is the same thing I found, not surprisingly. I guess if either you or I want to move forward we need to do a bit of research. What I learned though, because it never occurred to me, was that I could disable things like audio adapters and other unused devices on my server. There will be no music playing on that computer. The rest of the suggestions, like on demand CPU stuff and changing the USB behavior I'm not too sure about. It also recommended something about making some edits to the way the Ethernet adapter works. Still, a bit scary for the uninitiated.

[marko]

What I did was run

powertop --calibrate --html=powertop.html

and then let it run. it produces a html file called "powertop.html", I took the echo commands suggested in the html file and put them in /etc/rc.local

make sure to put as the first line:

#!/bin/sh

and make the file executable with

chmod 755 /etc/rc.local

and made a link from /etc/rc.d/rc.local to /etc/rc.local and made sure the rc-local.service was enabled. That worked for me but I made sure to not include the power management on my usb mouse which tended to break the mouse.

[DupermanDave]

Originally Posted by marko

What I did was run
and then let it run. it produces a html file called "powertop.html", I took the echo commands suggested in the html file and put them in /etc/rc.local

make sure to put as the first line:


and make the file executable with




and made a link from /etc/rc.d/rc.local to /etc/rc.local and made sure the rc-local.service was enabled. That worked for me but I made sure to not include the power management on my usb mouse which tended to break the mouse.

Pretty neat idea, thanks a bunch for that.

Any ideas on how I can determine the video card in use and how to switch cards?

Alrighty guys, so here's an update. I have not applied anything from powertop (I was just too lazy). But I did disable the ATI card and now my estimated battery life is 6+ hours. Well, it's fluctuating from 2 hours, 5+ hours, 6+ hours. So we'll see. But it looks like the hybrid graphics was the key. I'll play with the top suggestions and report back my findings.

-edit-
Just an update for you guys. I added the powertop suggestions to a startup script and it didn't seem to make a noticeable difference. Turning off the ATI card is what did it for me. Now I need to mess around with disabling the intel card and enabling ATI and see how much power I have to let go. I'd like to use the ATI card since I picked up my old 3d modelling habits again, but it's not necessary.

[george_toolan]

Which graphics chip do you have?

Try to enable power saving for the radeon driver http://www.x.org/wiki/RadeonFeature#...gement_Options

or install the proprietary Catalyst driver from rpmfusion

yum install kmod-catalyst

[DupermanDave]

Originally Posted by george_toolan

Which graphics chip do you have?

Try to enable power saving for the radeon driver http://www.x.org/wiki/RadeonFeature#...gement_Options

or install the proprietary Catalyst driver from rpmfusion

yum install kmod-catalyst

I'll give that a shot. First I need to figure out how to disable the intel card and have linux use the ATI card only.

I believe it's:
echo DIS > /sys/kernel/debug/vgaswitcheroo/switch
echo OFF > /sys/kernel/debug/vgaswitcheroo/switch


Is this correct?

[marko]

Originally Posted by DupermanDave

I added the powertop suggestions to a startup script and it didn't seem to make a noticeable difference

Make sure to confirm the powertop mods were actually applied, just re-run powertop again, and look at the "tunables" tab and you should see a whole bunch of "good" entries and almost no "bad" ones. I have one "bad" tunable left because the power saving on the usb mouse made the mouse worthless so I didn't use that one.

[DupermanDave]

Originally Posted by marko

Make sure to confirm the powertop mods were actually applied, just re-run powertop again, and look at the "tunables" tab and you should see a whole bunch of "good" entries and almost no "bad" ones. I have one "bad" tunable left because the power saving on the usb mouse made the mouse worthless so I didn't use that one.

I confirmed that already. Everything is good.

[marko]

another useful thing to try in powertop if you're on a laptop, try going to the "overview" tab and unplug the power brick so the laptop is running on battery only.

In that situation it will show the actual usage in total watts and the estimated number of hours and minutes left until 0% battery, for some reason the wattage used can't be shown when the AC is plugged in

[stevea]

It's no surprise when powertop only saves a watt or two. Screen brightness (as smr54 suggests) can have a bigger impact.

But something is is wrong here. My Lenovo T510 can squeeze out around 7 hours of browsing & light-load, maybe 8 with care. No way that's much worse the Win. So the question is - WHAT is burning power system ?


Try disabling various HW from the bios, and rebooting. *IF* you have a smart battery you might be able to read the dynamic charge/drain state with
sudo cat /sys/devices/platform/smapi/BAT0/power_now
or similar, but few vendors beyond Lenovo/IBM do so.

My suspicion is proprietary VID (but it's alway suspicious).