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Why Is Linux Notebook Battery Life Still Poor?
Ganty writes "I recently purchased a Lenovo W500 notebook, and after 'downgrading' to XP and creating a dual partition, I found that I had a battery life of nearly three hours using the long-life battery, at this point I was a happy camper because it means that I can watch a DVD during a flight. I then tried various Linux distributions and found the battery life under FOS to be very disappointing, with an average of 45 minutes before a warning message. After settling on Ubuntu I then spent three days trying various hardware tweaks but I only managed to increase the battery life to one and a half hours. Unwanted services have been disabled, laptop mode has been enabled, the dual core CPU reduces speed when idle and the hard drive spins down when not needed. Obviously Apple with their X86 hardware and BSD based OS have got it right because the MacBooks last for hours, and a stock install of MS Windows XP gives me three hours of life. Why is battery life on notebooks so poor when using Linux? Some have suggested disabling various hardware items such as bluetooth and running the screen at half brightness but XP doesn't require me to do this and still gives a reasonable battery life."
Is your screensaver running SETI?
Probably not a good idea if you want to conserve battery life.
I may sound like a jerkwad here, but why waste all that battery power watching a dvd when you could watch the divx version off local storage?
I don't know how you can expect us to fix your problems when you won't even take the time to read the documentation provided with the release.
In order to solve your problem, you need to set the RANDOMLY_DISCHARGE_BATTERY flag in the kernel source to "0" at compile time. Ubuntu, as well as other "desktop" distributions, set this flag to "1" by default for some reason, but simply installing the source packages and recompiling your kernel will fix the issue.
Honestly, a simple well-tailored Google search and a few measly days of sifting through the docs would have given you this answer without having to waste everyone else's time.
I was able to get my X41 tablet to have good battery life (a bit better than windows actually), but it took some doing. Powertop is a godsend, it pointed me to the i915 intel drivers as the culprit. Disabling DRI made a huge difference.
If you're running on an Intel platform, try running powertop. I can easily gain over an hour of battery life by disabling the services it recommends and reducing the screen brightness.
Here's some concrete evidence. Take a look at http://event.asus.com/eeepc/comparison/eeepc_comparison.htm in which Asus compares their different eee netbooks. Go to the battery life column and observe how, unfortunately, XP consistently outperforms Linux :(
And I have plenty of anecdotal evidence that power management works really well with whatever OS the computer was intended to run, and is alright-to-crappy with any other OS.
My MacBook Pro runs decently in OSX, and drains quickly in WinXP.
My HP Compaq laptop runs really long in Vista, though its still alright in Linux. (haven't done a comparison, though... But Linux still whines when battery #1 is almost dead, even if I have battery #2 available, installed, and at 100%)
The crux of the problem is that Linux is *rarely* the "intended OS" for any of these platforms, so the hardware manufacturer never invests any effort to make sure Linux power management drivers work correctly on them.
He only wasted you time and informed me and about everyone else who didn't know this. Thanks eln!!
On my Samsung NC10, Windows gives me about 6.5 to 7 hours of battery life, Ubuntu about 4.5 to 5.
Linux is a popular choice for netbooks, where battery life is paramount.
You mean "was", until Microsoft decided to keep Windows XP alive in the North American market for a few more years at bargain-basement prices per copy.
This really is an issue, and hardware support varies. Your notebook seems to include an ATI graphics card. That's probably your problem. Last I looked neither the open source, nor the ATI graphics drivers supported power savings on the ATI cards. I have an Asus F8Sv, which actually gets longer battery life in Linux, about 10 minutes, even though when running Linux, I have an external hard drive connected. It's got an Nvidia Geforce 8600 graphics card, with Nvidia's drivers. (Mind you, this is with OpenGL composting enabled, under Kubuntu (both 9.04 and 9.10) The other big one is Intel cards, which are supported for most of their power management features under the driver Intel helped write.
I dragged my old 15" Powerbook (1Ghz G4) out of retirement to have a look at Ubuntu, and while this may be a totally unfair comparison since the PPC build is hardly going to be the major focus of their optimising, but the PB did run much hotter under Ubuntu than it did under 10.4, and fan control was much less precise. It's not surprising, since Apple made the thing and obviously designed OS X around all the various controllers and sensors in it and Ubuntu has to run on anything you can throw it at, but that would be what I put this down to.
I was not sufficiently experienced at the time to do much to cure it, but I did install some software that had been written to make the fan control better which did help a little to keep it cool, but I'm not sure it would last long away from the power adapter.
This is just the same problem Noted in XKCD.
Good battery life is not cool. Open source software, especially a mutt like linux, is all about cool.
Good battery life requires annoyingly huge amounts of microoptimizations and chipset-dependent tricks. Which is most definatly NOT cool.
Test your net with Netalyzr
I get 10 hours on winxp on my eeepc, and 7.5-ish on eeebuntu.
I'd love to know what to do to optimize eeebuntu more, since that's what I need for work.
And I get 7-8 hours on ubuntu with my netbook. ... but I get 10 hours in WinXP, and that's the point. We need a comparison.
I would like to know which version of Ubuntu he has chosen and what other distros he's done. Off the top of my head for distros I'd try:
1) Ubuntu Netbook Remix (Both Gnome and KDE)
2) Moblin
3) Puppy
4) Macpup Opera
5) Xubuntu
6) gOS
7) Damn Small Linux
Yep - either those who target netbooks or those which try to be resource friendly. If one can run on a much older system well then a newer system it should hum, plus not be such a big hit on the battery life.
I call it 'The Aristocrats'
Some have suggested disabling various hardware items such as bluetooth and running the screen at half brightness but XP doesn't require me to do this and still gives a reasonable battery life
Are you sure? My netbook dims the screen when I pull the power cord on both XP and Win7... though it might be the BIOS doing that.
Anyway my suggestion is checking if ACPI works as it should. AFAIK laptops are notorious for buggy ACPI implementations that are only tested with Windows. Linux now pretends to be Windows XP when doing ACPI stuff, before that they noped out some part of the BIOS to make it work with Linux but that wasn't reliable. Look into if you can change how Linux does ACPI and try that.
kernel developers are smarter than that, and know that would be impossible to support. The real flag is PSEUDO_RANDOMLY_DISCHARGE_BATTERY.
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While I can't say that my Dell laptop's power management has been piss-poor under Windows (I can't really say that I used Windows on THIS particular computer that much, but I did on previous Dell models) and the power management was pretty excellent especially when the Intel speedstep software was running. If it helps, I run Fedora and Fedora and Dell laptops have been getting along fabulously for at least the past 6 or 7 version releases.
But one thing about running Windows that has always been a complaint and that's it's estimation for "time remaining." Whether looking at file transfers or remaining battery life, Microsoft ALWAYS seems to over-estimate "time remaining" or has at least reported the most optimistic figure possible. What I'm getting at is that it is QUITE possible that the Windows battery life you are reading is either untrue or unrealistically optimistic.
I know on my Dell Mini 9 running XP and watching video on battery power initially claims I have like 3 or 4 hours battery remaining, but before the two hour movie is complete, it wants to die.
The biggest source of battery drain on my netbook is CPU processing. No doubt with my other notebook, it would be hard drive usage followed closely by processor/gpu usage. This leads me to the next suggestion when using Linux -- use the graphics driver provided by nvidia or ati. They manage power better because they have the "secrets" that the GPL drivers don't have access to. Remember that a GPU is still a processor and eats power when processing.
Power management on laptops is all about paying attention to everything that draws power and being aware of it. For example, if it generates heat, it's using power... usually lots of it and cooling systems draw even more power as a consequence. Dial that speedstep down WAY low when unplugged.
This is, of course a vast simplification, but it gets the point across. The linked to article also shows how to use laptop mode to address these issues and extend batterly life (although, it seems to me that there is a trade off in the ability of journaled file systems to perform correctly).
It is no use setting sleep mode on the HDD if you leave Syslog running.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
Oh, hey, I know you. You're the tech support guy from A&TT I spoke with last week. When I asked why my cell phone didn't turn on anymore, you asked me to turn it on and go to the configure screen. When I responded that It wouldn't turn on. You asked me why.
XP's default file system is NTFS, and NTFS is journaled, so I don't think Linux gets an easy out there...
I'm surprised, my experience with Ubuntu 9.04 is very good on similar Thinkpad hardware. After upgrading from a decrepit IBM T42p to a Lenovo T61p (UXGA->WUXGA = similar screen size/power demands to the hi-res W500), I still get ~4:00 out of the Thinkpad extended battery.
Some ideas; perhaps these will be useful: .45A Seagate, and my experience was dramatic: 30-45min more battery time from that change alone. When I upgraded the recent hdd, I made sure to select one with less than .5A consumption.
- There is a bios setting on the Lenovo-era Thinkpads where you can force the screen to high brightness. My Ubuntu install manages this correctly (i.e. turns it on when on line power, off when on battery). However if yours does not kick the brightness to the normal range off line power, it'll kill the battery faster than any other factor. On high display brightness, you will be lucky to get more than 90min on battery.
- Hard drive power consumption does make a significant difference, and for that, Windows does tend to spin down the drive more frequently. With a high-load drive the difference can be pretty dramatic, but a more efficient drive closes the performance gap even if Linux isn't as aggressive with drive power management. For example, with the last upgrade to the T42, I replaced the old 1.1A IBM drive with a
- Check your display drivers. On the T61 with the default Ubuntu installation, the CPU load increased with the open-source video driver, because it's compensating for certain unknowns in the GPU by offloading to the CPU/being more inefficient. Loading the Nvidia driver not only increased performance (a lot), but (again) noticeably reduced power consumption.
In short, optimize, optimize, optimize.... and sometimes that means installing the right driver, not stripping things down.
I think not...(*poof*)
What do you mean? I just turned on my laptop linux and it always lasts ove
It's sadly true that almost all Linux applications / distributions have not taken writing-to-disk into account to reduce power. On the other hand, video / 2G / 3G graphics acceleration in hardware makes a huge difference, which is why I would really like to see more companies offering more in terms of stable hardware acceleration.
I've personally experienced issues with my laptop BIOS. It works properly in Windows, but a lot of the ACPI functions just flat out don't work in Linux. This is due to a compiler that lets the code compile with errors (Mainly functions that don't return a value when they should). This allows the BIOS programmers to be lazy, and write half assed power functions that don't work properly.
You can fix a lot of these issues by following the instructions in one of the links below to decompile that portion of the BIOS, and recompile it using the Intel compiler. It isn't easy, and certainly isn't something an user should ever have to do. It did fix a lot of the power issues with my HP laptop though (Running hot, not booting on battery power unless a key was pressed, hibernation).
See
http://www.osnews.com/thread?230516
http://ubuntuforums.org/showthread.php?t=1036051
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/272247?comments=all
In this instance, you can blame MS's poor compiler for Linux's poor battery life.
Because linux is fucking terrible for desktop use.
The battery life on my desktop is just fine.
Look in cron and disable stuff you do not use, especially locate.
Do not use the optical drive and make sure you are quiescing it.
Turn-off access time modifications for the hard disk.
Turn off fsck on boot.
Turn off periodic SMART status checking (on some drives this spins it up).
Tune the time to idle the drives and the periodic disk flusher (you have basically UPS with a laptop anyway).
Turn off swap.
Use a light simple window manager such as fvwm2 instead of something like gnome where lots of files are being accessed all of the time and you have many procs/threads running and the neat effects burn the battery.
Find the docs to your graphics drivers and tweak the tunables to use as little power as possible (this will give you much more than you likely expect).
Turn off bluetooth and wireless when you are not using it.
Don't use any of the crazy sound daemons.
You probably don't need wake-on-magic-packet for a laptop, turn it off, it helps a lot for some NICs.
Do you use multicast for wireless, most likely not, read the docs and figure-out how to get your driver to ignore that, it can conserve more power on some cards.
With some of the older chips USB was very power hungry in sleep (if that's your case tweak what you can so that it does as little as possible, likely turning off the wake on keyboard and mouse since you shutting and opening the lid should handle that).
Install a flash blocker and/or ad blocker and use gnash where you can instead of the adobe version.
As one of those non-techies who enjoys reading /. for the brilliant article summaries, insightful commentary and the sterling sense of humor of many posters, this little tale explains exactly why I am not willing to switch away from a mainstream operating system. I think I'm reasonably tech savy for someone who's never taken a computer programming class, but wow -- none of this makes the slightest degree of sense to someone like me. Can anyone explain why my initial gut sense is an over-reaction? Should my replacement computer (another laptop) be Linux (other than Apple)?
There are very few modern models where battery life is given as different from XP. In those cases the difference is rather small (not like what the article poster is experiencing). In at least one of those cases, the Linux hardware configuration is different than the XP hardware configuration. (Different flash drive size, there may be other changes such as a different WLAN card. For example, the Dells that have Ubuntu preinstalled have a different hardware configuration than non-Ubuntu Dells of the exact same model number.)
For example:
1101HA is given as being available with either XP or Linux. Only two battery life numbers are given, one for each possible battery configuration.
The 1002H is XP-only and seems to be one of the worst performers in the 10" class (5 hours)
In my experience, the most common causes of lower battery life under Linux:
NVidia chipsets. The power management in their driver is one of their lowest priorities. If you want games, you're going to have to sacrifice battery life.
Sometimes the "ondemand" cpu speed governor can be a little flaky and step to high speed way too quickly.
Keep in mind that's Asus's own Linux distro which most people regard as not being that hot. It may be missing some power tweaks available to other users. With the exception of Nvidia-graphics based laptops, I've usually been able to get much better real-world battery life on a machine with Linux than Windows. (Exception being that I haven't gotten FSB clock changing working on the Ubuntu partition of my Eee 1000HE yet - downclocking the FSB is the core component of Asus's "Super Hybrid Engine" power management scheme.)
retrorocket.o not found, launch anyway?
Is it one of the new "Super Hybrid Engine" Eees like the 1000HE?
You need to figure out how to underclock your FSB - that's really all that Super Hybrid Engine does on XP. Ubuntu's power management doesn't touch the FSB by default.
I haven't gotten around to doing this on my 1000HE yet.
retrorocket.o not found, launch anyway?
Because linux is fucking terrible for desktop use.
The battery life on my desktop is just fine.
Really? Battery life on my desktop sucks. It dies as soon as I remove the power cord.
Hardware specifically designed for the OS...
As far as I know, Windows does not tailor it's code to all Dell, Lenovo, Gateway, HP, and Asus laptops.
Come on, you refute your own argument. Hardware manufacturers do design their laptops to play well with Windows, in general. It is only recently that they have even considered installing linux as a feature. Most of them are probably still way behind on making their hardware play well with Linux. The main complaint I always hear about Linux is about having to do fancy things to make drivers work. So all comparisons are valid.
Well, DUH, it HAS to be perfectly optimized for the hardware.
Battery management requires checking every single pin on your hardware and ensuring that you've set the i/o correctly for sleep mode.
If you have even one pin with a pull-up resistor set as an output, then you'll get lower battery life than the nominal case. If you have just random I/O on unused pins, then you're going to get greater drain than ideal.
I'll qualify that statement by saying I'm an Electrical Engineer with embedded experience. One of the products I worked on was a GPS / VHF tracker with a 12uA standby current. Another was a VHF tracker with an 8uA standby current. Slight modifications to the firmware would bring the standby current up to 50-100 mA. That's more than 1000x more standby current.
My experience dealing with Linux developers (and realistically, software developers in general) is that they're all terrible at determining the link between hardware and software. Look at the derision you get online towards C. Linux devs are worse -- if you're not running their exact hardware on a machine you bought in the last month, then it's your problem, not theirs. "Weird, it works here. Have you tried recompiling the drivers?"
It's fairly easy to map these pins, BTW. All you have to do is set everything to an output, set it to 0, and then turn everything to an input. Everything that's high has a pullup resistor. Do the same with 1 and everything that's low has a pull-down resistor. Now you know which pins must be inputs when you're not using them.
Of course, since you taught yourself programming with Ruby on Rails, you know all this, right? It's not like you'd have to have some low-level knowledge of the hardware in order to effectively make a complete synergistic hardware and software package.~
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ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
Just my own experience, but I've never seen differences in battery life that are this extreme. Linux has always been worse, but never more than about 10% on the laptops I've used, with one exception.
The only time I've seen a huge difference is on an HP laptop that I currently use as an SVN/Trac/CUPS server. The machine has a BIOS bug that prevents me from using ACPI in Linux, and HP never released a patch to fix it. The only way to keep the machine stable in Linux is to boot "acpi=off, noapic, nolapic". With no real power management, it drains mighty fast, even with all the hardware that gets disabled booting this way (webcam, wireless, etc).
On the other hand, a few years ago I owned a wonderful Sager laptop. With two double capacity batteries and a regular capacity battery, I could get a full 20 hours of battery life from the three (8 hours for double, 4 for regular) running Linux (Gentoo at the time), which was within 1 hour of the average total when I ran XP.
Linux does have worse battery life, for a number of reasons, but the difference doesn't seem significant on most hardware. It all seems to depend on hardware quirks in your machine.
It is notoriously hard to work with power management features of notebooks, because it is hard to find a really ACPI-compatible BIOS. Most of them are broken in some way, or require undocumented voodoo and magic values to behave. There is really no solution to this unless: a) Manufacturers get their shit together and ship functioning hardware, not hardware that accidentally happens to work under Windows (systemic approach); b) Linux gets more mindshare and those issues get sorted out on a per-device basis (band-aid approach). a) is very unlikely, since shipping functioning hardware brings no obvious reward to the manufacturer. Therefore we can only hope for b).
Note that this is not limited to ACPI. In almost every area, there are hardware products that do not comply with specifications they are supposed to comply with, lie about supported features when probed, have bogus device descriptors, reuse the product ID of a different device, do stupid things when supplied valid commands it doesn't expect, etc.
Those who would give up liberty to obtain working drivers, deserve neither liberty nor working drivers.
That's nonsense. It doesn't explain why designed-for-linux netbooks like the Linux Eee systems perform as poorly as they do.
I would bet that the problem can be largely attributed to 1) vm.swappiness being set too high and (IMO every laptop user should set vm.swappiness = 0 unless they know a higher metric would help their specific operation behavior) 2) ext3 sucks horribly, 3) linux often defaulting to the 'standard' and ignoring/overriding hardware bugs which might be accounted for in the closed drivers (such as with the BIOS), 4) hard drive power management options/defaults are usually not very good and do not account for/override filesystem settings.
There might be something else to it, too. I've personally never had a laptop that got better battery performance in Linux than in Windows; it's always just been Part of the Deal of running Linux to get worse battery life, despite what I've heard others say.
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
I'm running a stock Ubuntu install (except Nvidia drivers) and my battery life is great. The sleep mode works, too. The key to running Linux is using compatible hardware and it works very well. Ubuntu really has made the user experience better than Windows. I'm not saying that Linux offers the same breadth of software but on compatible hardware is really is slick. I was at my brothers and wanted to print a file. I plugged the USB cable in and the selected the printer while printing from the application. No downloading drivers, no loading crapware from a CD, just plug in and print.
"Linux is dead, long live Windows 7!"
er, don't know about dead, and I wouldn't say "long live windows 7", but I will admit the battery power options are very impressive on Windows 7. Not only can you change the obvious like cpu speed, but you can go all the way down and adjust how long the CPU fan should be on if you're on battery, and it can change according to which battery profile you choose. It has more options than I've ever seen on any program, even more than NHC.
my karma will be here long after I'm gone
I think many of the posters here, who all have great ideas and suggestions, are missing the point of the OP.
Why is an out-of-the-box XP machine performing better than an out-of-the-box Linux machine?
The Linux community shouldn't be saying "try this" or "tweak that" or "install this device driver" or "switch your hardware"... they should be working on building those into the next revs of the OS and making them part of the default configuration (or at least an easy prompt like XP offers).
-David
Well, perhaps it's the distro? Or the hardware. On my Dell Vostro 1000 with a 6 cell battery, I get at absolute maximum 4 hours of battery live on WinXP. On a slightly stipped-down Mandriva Linux I've managed to squeeze 6 hours of use out of it while watching movies. Of course, you could say this isn't an _entirely_ fair test as I was running both the system and the movie from a USB flash drive, but considering I did nothing special in the installer, just told it to install to the flash drive, I'd say it's fair - if you could install Windows to flash that easily I'd run it from one too. Plus with my full version of Mandriva 2009.1 using KDE4 I still get at least as much battery life as I get on XP - and it actually last longer than XP does for gaming (specifically World of Warcraft).
I have found that if your kernel wasn't compiled with the correct CPU drivers, the CPU might not be speed stepping. If you are using gnome you can use the gnome CPU applet to see the actual CPU speed. In my case, (HP DV1000, Pentium M 1.73 CPU) with ubuntu Hardy, the CPU steps fine, but having the "correct" CPU voltage and speed values hard coded on the OS kernel prevents me from underclocking and undervolting the laptop under linux (without compiling a custom kernel), which is easily done in windows with software such as Rightmark Clock Utility. So my battery lasts 1:30 hours with Ubuntu and almost 3 hours on XP. Guess which I use the most for school even though I strongly prefer FOSS?
Greetings, programs!
Sounds like you are simplifying the situation alot. Yes thats how you do power management on tiny microcontrollers, but that has nothing to do with power management on a typical PC.
Video card have ways to stop clocks in certain areas of the chips, this is the main way power is saved, same with CPU's. These devices don't have I/O pins in the same way microcontrollers do, usually all the buses are tri-state and there is no need at all to 'set' something to input or output or high or low, you simply high impedance the whole bus connection.
What you are talking about has nothing to do with programming on modern computers, you can't just tell your video card what pins to set as output and input, you have to talk to it over a bus, and it runs its own firmware/bios that may have calls that make it disable clocks in certain parts of its chips and high empedance certain bus lines etc. Knowing what these commands are and how to talk to chip when the manufacturer doesn't release any details, just a windows binary driver is the whole problem in the first place.