Longer battery life for Athlon64 and Turion laptops

[Elmo234]

Hi!

I started developing a new program. The first version is out now
It is a daemon to replace powernowd, cpufreqd, etc...

It is more configurable and it lets you override the voltage of AMD K8 core cpu's (Athlon 64, Opteron and some Semprons) and Pentuim-M (centrino) and Celeron-M from Intel.

After a few test I found that my athlon 64 processor was able to work at 1,2v at 1800Mhz and 0,8v at 800Mhz (AMD it has to work at 1,5 and 1,1v). This makes the cpu run cooler and I have almos 30 minutes more of battery life.

So you can have a try if you want...

www.tuxamito.com.es/cpupw/ Here you will find a lot more of information.

Please, write your comments...

[Gnufsh]

Sounds interesting. Planning on writing an ebuild for it?

[mudrii]

Nice and really cool if you can make an ebuild.

Is it work on Big AMD 64 dual core too ?
_________________
www.gentoo.ro

[Elmo234]

Yes it works for dual core cpus. I tested it on mine

It is also supposed to work on multi cpu systems and hybrid systems (1 dual core cpu and a single core cpu)... But I haven't tested that...

This is just the first release. Next week I will release a new version that solves some isues. I also want to make some scrips for starting / stopping the daemon.

Then I will try to write and ebuild. The problem is that I have never written one. I hope it is not too difficult

[Plugin_baby]

Sounds good, the short battery life of my turion64 laptop really annoys me...

Elmo234, you say you get an extra 30 min. with this, how long do you have in total?
At 800MHz (ondemand) I still only get about 2 hours.
I know that battery life also depends on the model, but I'm curious about what others are able to get

[Elmo234]

My notebook is an ACER 1501 LMI with an Athlon 64 DTR processor. At 800 Mhz I can change voltage from 1,1 to 0,8v. That reduces the energy needed by the cpu in a 47%. This pushes battery life from 2 hours 30 minutes to over 3 hours.

But in a Turion system you won't be able to reach such a high difference because you processor uses lover voltage by default and because Turion uses about half energy that an old Athlon 64 DTR.

But you can try it. Maybe you have 15 or 20 minutes more of battery life.

[Elmo234]

I just released a new version (0.1.1) that solves some bugs. The ebuild will come soon (in two or three days).

[Voluspa]

Ever since Linus "stole" my one and only C-state for reducing power usage in kernel 2.6.15 (see http://bugzilla.kernel.org/show_bug.cgi?id=5767 ), I've patched it back with:

[Elmo234]

Thank you Voluspa for such a great comment to the program. And thanks for thanking me

[Voluspa]

I've read the interesting (and long-running) gentoo AMD64 thread on undervolting, where hopes of a kernel or at least a distributor patch acceptance is expressed. That will probably never happen. Operating out of spec, even if it is a user choice, would place them in a most unwanted liability. Consider for example the powersaving AMDK7 patch that has been floating around since 2002. Len Brown, the ACPI maintainer from Intel, had some final strong words:

[PATCH] amd76x_pm: C3 powersaving for AMD K7
Thread start http://marc.theaimsgroup.com/?l=linux-acpi&m=113873375729153&w=2
--quote Len Brown http://marc.theaimsgroup.com/?l=linux-acpi&m=113895655522773&w=2 --
[...]
How about if we put it this way...
If the ACPI maintainer were an AMD employee,
and he accepted a patch like this specific to Intel hardware --
a patch that rejects whatever validation Intel, the BIOS
vendor and the board vendor have put into the product --
I'd call for his expulsion for ineptitude.

If somebody from AMD steps forth and says that hey, their hardware
is broken if used in the standard way, but that this "logic around"
is a valid model-specific workaround -- then we have something
that MAYBE we can work with. Otherwise, do whatever works for your
own system, but it would be reckless of us to put stuff like this
in the upstream kernel and then ask distros to support it.
--end quote--

Undervolting has a strong aura of "recklessness" and a userspace tool like CPUPW could well be the only patch-free avenue for the foreseeable future.

Speaking of which, Daniel, when university has eased its grip could you contemplate a runtime switch along the line of "--maxfreq <frequency>"? When trying out voltages my 2200 and 800 MHz speeds posed no problems. The 800 could be had by using your "--laptop" switch and doing an "echo -n '1'>/proc/sys/vm/laptop_mode", but the intermediate speeds 2000 and 1800 really had me stumped for awhile. Experiments caused a lot of "ignoring illegal change in lo freq table-0 to 0x0 -- transition frequency failed" in /var/log/syslog until I finally could clamp the speed AND retain correct voltage by doing:

echo -n "1800000">/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
(using this cpupw.conf)
1
1
304
4
2200000 22 -1 -1
2000000 22 -1 -1
1800000 22 -1 -1
800000 30 -1 -1
1

echo -n "2000000">/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
(using this cpupw.conf)
1
1
304
4
2200000 16 -1 -1
2000000 16 -1 -1
1800000 22 -1 -1
800000 30 -1 -1
1

Not pretty If we want to find _stable_ voltages, testing each level is a must. And, as it turns out, that requires quite some work. Taking a hint from the other undervolting thread, I downloaded GIMPS (mprime) http://www.mersenne.org/freesoft.htm and ran the torture test (-t). Heh... my value for 2200 MHz, which was stable in Neverwinter Nights, miscalculated after a mere two minutes. Fixed by upping it another 50 mV. I then ran each speed - deleting local.ini in between - the recommended minimum of six hours without errors.

But, and this really underscores the need for multiple test-tools, entering Neverwinter Nights again I experienced a crash while loading an area. Knowing that this is more disk than CPU bound I guessed that the lower frequencies also needed a little extra juice. Giving both 800 and 1800 speeds another 50 mV and walking around the map for an hour finally convinced me of machine stability.

Examining by "cat /sys/devices/system/cpu/cpu*/cpufreq/stats/trans_table" (cpufreq_stats and freq_table modules loaded or builtin) after the game is another must to verify that you've really exercised all the CPU speeds.

Final cpupw.conf for me, and me only

1
1
304
4
2200000 12 -1 -1
2000000 16 -1 -1
1800000 20 -1 -1
800000 28 -1 -1
1

Ergo:

[octapus]

Very useful program indeed.

I have an AMD 64 3200+ and the following working configuration:

1
1
304
3
2000000 16 -1 -1 <= 1150mV from 1500mV
1800000 20 -1 -1 <= 1050mV from 1400mV
1000000 24 -1 -1 <= 950mV from 1150mV
1

Even under full load the second fan is never activated which lowers the amount of noise the laptop generates.

I didn't extensively test the stability but there are no problems till now.

Let me also say that there were messages similar to what was mentioned before ("powernow-k8: error - out of sync.....") from time to time.

[widan]

[superwutze]

i have some trouble using cpupw.

my system is a tyan s2875 k8w and i have two opterons 246 on it.
cpupw -s gives the following:

[pagaman]

Just a quick note to say thanks.
I've got an Acer aspire 1520 something, and I've just knocked 200mV off all 3 of my settings.
This is great
I can probably knock more off too...

My config:
1
1
304
3
1800000 10 -1 -1
1600000 14 -1 -1
800000 26 -1 -1
1
_________________
History only remembers great people by forgetting their mistakes.

[Elmo234]

I just released a new version... cpupw 0.2.0. But I haven't test it much. The main new things are:

- It is supposed tu run on multiprocessor computers (the other versions didn't, there was a bug) and I say supposed because I don't have a multiprocessor system to test.
- Possibility to adjust VID and FID manually.
- Detects which governor is running and gives warnings if it is not "userspace".
- Now the FSB frequency is detected (the theoretical and the real one).
- You can modify the VID by a constant, passed as a parameter. This let's you decrease, for example, 0.2v in every step without creating a config file.

the web page is the same: http://tuxamito.com.es/cpupw/

please, give me your reports

thanks

[kristoffer]

This program is great! I'm using it on all of my computers now. I do, however, want to be able to set a bound for the frequency values, i.e. something equivalent to scaling_max_freq and scaling_min_freq, so I did a little hack to add that functionality. In order to apply the hack, put the code below in a patch file in the cpupw-0.2.0/src directory, apply the patch to cpupw.c and compile:

[/carlito]

I really can't understand this program. I own an MSI megabook S270 which hosts a Turion MT30 cpu.