Linux kernel 2.6.38 - major power usage increase

[Aging Technogeek]

These three articles from Phoronix point out a major problem with the 2.6.38 kernel . It consumes up to 20+% more power than older kernels. This could cause significant reduction in battery powered run times on laptops and netbooks.

http://www.phoronix.com/scan.php?page=article&item=ubuntu_natty_power&num=1

http://www.phoronix.com/scan.php?page=article&item=linux_mobile_uffda&num=1

http://www.phoronix.com/scan.php?page=news_item&px=OTM2NQ

It is apparently a kernel regression but at present there is no precise information as to cause or workarounds (if possible). Phoronix is continuing to investigate.

Since the 2.6.38 kernel is available via Update Manager for LMDE and Mint Xfce, and is the default kernel in Ubuntu 11.04 and will be in Mint 11, this is something to watch closely.

[GeneC]

Perhaps this problem is something that the 2.6-38 Liquorix kernel addresses?

I have been running the latest Liquorix (now 2.6-38-3) kernels for some time with none of the apparent problems that the new Debian 2.6-38 kernel seems to be having with so many LMDE users.

I dont have a laptop, so not aware if there are increased power issues with Liquorix.

[Aging Technogeek]

The tests were run using all Gnome versions of Ubuntu back to 8.04 for comparison, with the default kernel in each. No custom kernels like Liquorix were used

[Aging Technogeek]

Additional information just published by Phoronix

http://www.phoronix.com/scan.php?page=news_item&px=OTM2OQ

[lollo6]

Anything new about this problem? I'd like to install this kernel since it should support the HD3000 intel graphics, but if the price is an increased consumptions maybe I should wait.

[Zero Prime]

I'm using the 38 kernel on my laptop and haven't noticed any major power problems. The battery may drain a little faster, but not fast enough that I can notice it with out timing it.

[Nick_Djinn]

I dont really care when it comes to my desktop. I welcome the increase in speeds, the adoption of the 200-odd lines of code, changes to the scheduler that some of us have been harping about forever, and the hardware support. Google, despite its global ambitions, has been really helpful in developing the kernel for the end user, rather than an afterthought for the server market (which contributes greatly to functionality, but not necessarily the most efficient way possible when it comes to desktop performance).


This might be a concern on my laptop.

Are there some applications that can help reduce power consumption?

[Aging Technogeek]

After reading the Phoronix articles in depth and checking their tests, it seems that this will only be a problem under heavy usage. All the Phoronix tests were designed to test power usage under heavy loads, and they were mostly run on somewhat older IBM Thinkpads (and one EEE netbook).

The IBM units all showed up to 25% increases in power usage compared to the same unit running an older kernel, but the netbook did not exhibit the same degree of power usage increase as the IBM laptops. This seems to indicate that the degree of increased power usage may vary from one manufacturer to another so you should try things on your system and see if the power usage is excessive.

This may not be acceptable if you only use your laptop for light duty such as web surfing and email.

[Nick_Djinn]

Then again, inability to take full advantage of the massive amounts of ram in modern hardware, and performance settings that are more appropriate for servers than for powerful desktops used as intensive high performance workstations might not be acceptable to others.

There should be some welcome changes in the new kernel.

[phaed]

Will the 2.6.38 kernel be the default in Mint 11? It is the default in Ubuntu 11.04.

[Nick_Djinn]

Most likely I hope. I NEED the new kernel since the old one does not support my hard ware.

3d acceleration is also better in the new one.

[ibm450]

yes i have also noticed this on my laptop - asus ul50vt - more power usage along with alot more heat generated that has the fan running alot more often.

noticed no difference in 2.6.39rc5 either

[craig10x]

Yes..it is actually in fact a a very SERIOUS PROBLEM...especially on laptops...while not everyone is experiencing it, MANY people are....i heard there were over 100 bug reports filed on this kernel problem...I have Mint 10 main edition installed on my 2 yr old toshiba laptop (so we are not talking about ancient equipment here...lol) and the fan almost never needs to come on...laptop runs nice and cool...

But i have been testing Kubuntu 11.04 on live cd on it (both 64 bit and 32 bit versions) and my Fan is running CONSTANTLY....obviously to keep the computer from overheating because of the massive increase in power consumption...And yes, Mint 11 has that same new kernel and also does the SAME THING on my laptop when i ran the live dvd!

It ALSO DID IT when i was still running LMDE (which i don't anymore) when i got the update for the new kernel and had to boot into the previous kernel to AVOID THE PROBLEM....

I understand that debian and ubuntu are well aware of it, but until it is fixed i cannot even consider installing any system using the new kernel...
I hope that when fixes comes down for this problem, that it is posted to this thread, so i will know it is safe for me to install

By the way, i don't even use my laptop portable and on battery power (if i did i would not be surprised if my operating time would be cut down drastically from the power drain)...I use my Toshiba 17 laptop as my DESKTOP and it is ALWAYS ON AC POWER...

[Nick_Djinn]

Im using Ubuntu 11.04 on my Toshiba and its running nice and cool.

Do you think it could be a problem with certain graphics cards or CPUs? What is your hardware?

Running from disk is usually more intensive on resources and Kubuntu can be pretty heavy.

[craig10x]

Im using Ubuntu 11.04 on my Toshiba and its running nice and cool.

Do you think it could be a problem with certain graphics cards or CPUs? What is your hardware?

Running from disk is usually more intensive on resources and Kubuntu can be pretty heavy.

Interesting....although i also encountered the problem running mint 11 live dvd and also when i had a hard install of LMDE when the new kernel was added in...and when i ran LMDE and booted into the previous kernel (the one that LMDE was initially installed with) the power problem disappeared INSTANTLY...fan nice and quiet...no surge in power...no overheating...

And i recently replaced LMDE with Mint 10 main edition (which as you know, uses the previous kernel) and same deal there..fan almost never comes on at all...nice and quiet...no overheating...no huge increase in power consumption (said to be as high as 25%)....

My Toshiba Laptop is about 2 years old and has an AMD Turion X2 and Ati Radeon Graphics...though from the various posts and forums that i saw, it is NOT hardware specific....intels get it, amds get it...64 bits....32 bits...newer computers...much older ones...laptops, netbooks, even desktops! But not everyone gets it (like you for example...LOL)...but there has been enough reported for both debian and ubuntu to declare it a major bug in the kernel...

[Nick_Djinn]

Maybe the OS has become sentient and its punishing people who are wicked? Or maybe its spyware processes going on in the background and its targeting anyone who has ever said anything remotely radical on an online forum.

9ho6

[z06gal]

I am running Mint 11 RC 32bit and have not noticed any problems at all with this kernel. I'll keep a watch on it though just out of curiosity. Thanks for the info.

[Aging Technogeek]

I think Nick Djinn may be on the right track with his comment that this power use problem may be hardware related. The Phoronix tests were done on a random collection of 3 IBM Thinkpads they had available and one Samsung netbook. The Thinkpads all exhibited the problem to varying degrees but on the netbook, power usage was nearly comparable ( except for high load graphics) across all Ubuntu versions tested

Toward the end of this article

http://www.phoronix.com/scan.php?page=article&item=ubuntu_natty_power&num=1

this statement is made

With the Atom netbook, the Ubuntu 11.04 release wasn't always worse than Ubuntu 10.10, but it was worse under graphics. With the other systems, the regressions occurred regardless of idling or load for the disk, CPU, or GPU.

This seems to indicate some hardware specificity. Of course, to prove this would require more extensive testing.

Another unanswered question. Does this effect show up on AMD processors? Or is it only an Intel bug?

[craig10x]

My toshiba laptop has an amd processor, so it doesn't seem to be specific to intel...In another forum, someone also with a more recent toshiba like mine but has an intel did not have the problem at all...weird right?

And as i mentioned, in my case, i got it on hard install LMDE when using this kernel (but not the previous one), on live dvd run of Mint 11, as well as live cd run of Kubuntu 11.04...But again...not at all on previous kernel hard install (my current system) of Mint 10...

[ibm450]

Im using Ubuntu 11.04 on my Toshiba and its running nice and cool.

Do you think it could be a problem with certain graphics cards or CPUs? What is your hardware?

Running from disk is usually more intensive on resources and Kubuntu can be pretty heavy.

Interesting....although i also encountered the problem running mint 11 live dvd and also when i had a hard install of LMDE when the new kernel was added in...and when i ran LMDE and booted into the previous kernel (the one that LMDE was initially installed with) the power problem disappeared INSTANTLY...fan nice and quiet...no surge in power...no overheating...

And i recently replaced LMDE with Mint 10 main edition (which as you know, uses the previous kernel) and same deal there..fan almost never comes on at all...nice and quiet...no overheating...no huge increase in power consumption (said to be as high as 25%)....

My Toshiba Laptop is about 2 years old and has an AMD Turion X2 and Ati Radeon Graphics...though from the various posts and forums that i saw, it is NOT hardware specific....intels get it, amds get it...64 bits....32 bits...newer computers...much older ones...laptops, netbooks, even desktops! But not everyone gets it (like you for example...LOL)...but there has been enough reported for both debian and ubuntu to declare it a major bug in the kernel...

wow, what an interesting overview. i too loaded back into the original kernel in m10 (2.6.35-22-generic) and the fan and heating has dropped drastically also o_0

now this has become real interesting and overly concerning. tbo, this is the first time i actually ran the OS (m10) in the very original kernel and first time ive noticed how quiet the laptop is running....