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PowerTOP tops up to 2.1

PowerTOP tops up to 2.1

Posted Aug 31, 2012 12:34 UTC (Fri) by wookey (subscriber, #5501)
Parent article: PowerTOP tops up to 2.1

New powertop is nice, but it seems to have lost my favourite feature which was the reading of current power consumption in Watts. Is there a good reason why that is no longer printed?

Currently I can twiddle params between 'good' and 'bad', and I can see how that changes the fraction of time in various states, but not the _actual power consumption_ which is what I am trying to optimise.

I can sort of guess by wiating a while and looking at the 'time left' pop-up in xfce4-power-manager, but that's still not actual current average consumption, although I naively hope it's linearly related to it.

And more help on the what the various params actually _do_ would be really nice. For the non kernel-power-management guru most of it is highly cryptic. Some idea of each tradeoff and associated risks would be very nice.

In practice I've found that turning everything to 'good' still leaves my machine working, and this article has allowed me to discover there there is an easy way to put all that lot in my 'onbatt' script, which is great. Some of them should perhaps be on for mains use too though - and I have no idea how to work out which.

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But what does BAD->GOOD do?

Posted Aug 31, 2012 15:06 UTC (Fri) by spaetz (subscriber, #32870) [Link]

My biggest gripe (I am sure I have overseen it), is that while I can make myself happy by transitioning everything from BAD to GOOD until the next reboot, I have no way to find out what this actually does.

E.g. how would you learn that "Turn off NMI watchdog" translates into

"echo 0 > /proc/sys/kernel/nmi_watchdog" (this took me quite some googling and one one of the easier things to find out).

I would appreciate if powertop could tell me what tweak it actually applies when hitting <ENTER>. Teach me to fish, don't just hand me one :-).

But what does BAD->GOOD do?

Posted Aug 31, 2012 17:14 UTC (Fri) by hummassa (subscriber, #307) [Link]

Version 2.1 does just that.
But I didn't like the system after I transitioned (ok, I did everything together and shouldn't have done that...), it became strange and unresponsive.

But what does BAD->GOOD do?

Posted Sep 1, 2012 2:15 UTC (Sat) by spaetz (subscriber, #32870) [Link]

Thanks that is good to hear. But I just opened Powertop 2.1 and could not find anything like that. Can you enlighten me?

But what does BAD->GOOD do?

Posted Sep 2, 2012 21:09 UTC (Sun) by drago01 (subscriber, #50715) [Link]

From the article:
PowerTOP's other mode is report generation, which you can invoke by running either sudo powertop --html or sudo powertop --csv. [...] A bit more interesting, however, is the HTML output's Tuning tab, which includes the command necessary to change each "Bad" setting

But what does BAD->GOOD do?

Posted Sep 3, 2012 8:42 UTC (Mon) by spaetz (subscriber, #32870) [Link]

DOH, thanks for that! Clearly, I need to brush up my reading capabilities.

PowerTOP tops up to 2.1

Posted Sep 3, 2012 23:33 UTC (Mon) by Baylink (guest, #755) [Link]

Well, wookey, thank you for saving me a lot of time and trouble. I've got enough info out of powertop 1.13, and if 2.x doesn't show me watts anymore, I'm not sure I'm going to bother...

Showing watts

Posted Sep 3, 2012 23:45 UTC (Mon) by corbet (editor, #1) [Link]

It shows power consumption just fine on my machine. Like 1.x, you likely need to be off AC power before ACPI will tell powertop what the current usage is.

Showing watts

Posted Sep 4, 2012 0:33 UTC (Tue) by wookey (subscriber, #5501) [Link]

Aha. That is indeed the secret. Unplug the power, get power consumption stats, plug it back in and they disappear. I suppose this is a feature of ACPI and/or what the hardware can measure. I'd have been much less confused if there was some kind of clue that this info would be displayed when off mains, such as a placeholder.

Showing watts

Posted Sep 4, 2012 0:40 UTC (Tue) by Baylink (guest, #755) [Link]

Oh, that.

Silly me. Hadn't even thought about that. Thanks.

Showing watts

Posted Sep 4, 2012 0:45 UTC (Tue) by mjg59 (subscriber, #23239) [Link]

ACPI doesn't report power consumption, it reports change in battery state. So if you're on AC, the interface that would tell you power consumption is instead telling you how fast your battery is charging…

Showing watts

Posted Sep 4, 2012 23:15 UTC (Tue) by zlynx (subscriber, #2285) [Link]

And you should note that in most cases, the reported watt usage is correct because the battery hardware is working properly.

In some cases the watt usage will be incorrect because your battery is borked. I've seen this happen.

If your battery drops from 100% to 60% within 15 minutes, there is almost certainly something wrong with the battery. Or you are running an Alienware. :-)

Showing watts

Posted Sep 5, 2012 23:25 UTC (Wed) by nix (subscriber, #2304) [Link]

... or it's an old battery with correspondingly high internal resistance due to oxidation. (This generally exhibits itself as a battery with 'high' capacity that drops fast, in my experience.)

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