Is PowerTop Still Useful For Extending Your Battery Life?

[phoronix]

Phoronix: Is PowerTop Still Useful For Extending Your Battery Life?

Three years ago Intel had released PowerTop, an open-source utility for Linux that would analyze how well your laptop was conserving power and would allow users to easily tune their system for maximum battery life via simple power optimizations. By simply running this utility, some users were able to significantly extend their battery life. However, is this utility still useful and needed with a modern Linux desktop? The most recent release of PowerTop (v1.11) was a year and a half ago, so we are seeing how well PowerTop is still able to reduce the power consumption of Intel notebooks/netbooks running Linux.

http://www.phoronix.com/vr.php?view=15083

[Ragas]

But you know that this is not the only use for powertop, do you?!

I once had a Volume control plugin wich was responsible for ablot 30% of my system wakeups. since this isn't funny on a laptop I replaced it with a different one so to preserve Power.
And right now I see that the plugin container of firefox is causing 25% of the wakeups, which tells me that there are some stupidly flash ads, which aren't even seen in foreground right now that consume my poor battery. so I might think about blocking them.
And don't forget, that working around one offending thing actually cuts your wakeups more than just the percentage the tool shows, because you also get less kernel calls and stuff.
When is have a lot of pages flash sometimes prevents me from having an idle cpu.

Btw. why must everyone use flash for some lousy ads? wouldn't an animated gif or something do the same job?!

[bibiu]

That article is retarded sorry.
PowerTop is not made to run and hit the keys to activate whatever it says and boom magic battery life - windows wizard style, aren't you a tech site supposed to know that?

The tips are just a fun option they added. The primary usage of powertop is being able to see which application is causing wake ups and draining the battery in order to optimize them. (or kill them)

You got it quite quite wrong

[Craig73]

Well, I for one like the higher level questions of if Linux is starting to polish/refine, so I don't find it a 'retarded' article at all in concept.

I don't think I should have to tweak/tune Linux for to get better video/battery/performance/features.

That might have been a reasonable expectation in the earlier days where most everyone was a developer-user or power-user and the Linux/FOSS platform was a collection of bleeding edge where roughness and manual tweaking was an acceptable trade-off to have as-functional-as-possible-while-evolving desktop, but things are good enough now that refinement needs to be/is happening --- so good on Michael for exploring these questions.

Now on the true use of the utility - well whatever, people use and abuse software for whatever they think it's useful for (hence the nature of hacking).

It's obviously not being used (enough) for fixing CPU abusive problems (at least by Adobe) because I can walk away from my laptop for any length of time and come back and it's burning up (not quite idle)

[jboehm]

PowerTop is also very useful for confirming if Core i* family of processors utilizing Turbo Frequencies. In addition it gives some view into CStates utilization. Although turbostat gives a more complete picture.

http://kernel.org/pub/linux/kernel/people/lenb/acpi/utils/pmtools/turbostat/

[garytr24]

linux-phc

unfortunately, it'll never become mainstream because it's risky , but if you really care about power consumption and heat, use linux-phc and try to undervolt your chips (it won't fry your chips, but it could cause data loss if it locks up during testing). I get about 20-30% more practical battery life by pushing down all the voltages on my core2 duo p8400 thinkpad sl300. Makes a world of difference. P=IV and current goes down as voltage goes down, so you get large savings. Very noticeable especially when compiling with make -j3, the heat of the laptop is about half as bad with aggressive undervolting plus a little margin of a couple of ticks for stability.

[rohcQaH]

Unless your CPU was designed to handle lower voltage, undervolting can actually fry it. Good thing it's not mainstream.

Anyway, powertop does still increase my battery life. Not because I've installed it, but because it's in the hands of the developers and distributors. If there's no more improvements to make by hand-tweaking my installation, then powertop has achieved what it was designed for: good distributions that don't waste power.

[Ragas]

Unless your CPU was designed to handle lower voltage, undervolting can actually fry it. Good thing it's not mainstream.

and which processor that can change voltages from software isn't designed to handle lower voltages?!

Plus I've never ever heard of a broken CPU because of too low voltages and I provably never will because to less energy will never have the energy to fry an electric connection. (That would be like saying your computer will break if you shut him down, because the shut down voltage (0V) would be too low.)

some comments are just too stupid.

[garytr24]

yea, all higher voltages do is make the logic transitions between cycles sharper plus make the design more robust to noise (same noise plus higher voltage means better SNR). But I'm thinking CMOS, don't know how this applies to modern designs. Overclocking and undervolting mess with the slope of the the on-off transitions and the length of time the peaks and valleys stay stable. In once case you're increasing current and heat, and in the other, you're decreasing it. but IANATransistorExpert

[rohcQaH]

Plus I've never ever heard of a broken CPU because of too low voltages and I provably never will because to less energy will never have the energy to fry an electric connection.

I can't find the link right now, but IIRC that's true only if you look at an isolated CPU. There's more components inside your computer.

If transistors cannot function your CPU will output random nonsense. Writing weird memory values causes your programs to crash. Violating bus protocols opens up an entirely different class of failures. I doubt that consumer grade hardware is meant to fail gracefully there.

Also, your CPU gets signals from everyone else, and those are at a fixed voltage. There you'll see an increased voltage differential when undervolting your CPU which may or may not harm whatever's responsible for the conversion.


So yeah, slightly undervolting will probably result in system crashes before it physically damages anything. But if you lower it too far and got a bit of bad luck, you may end up with broken hardware.