user undervolting

Message

just-linux · Post by **just-linux** » Mon Sep 03, 2007 3:14 pm

For my Intel Pentium M Dothan (2000MHz), undervolting does quite a big difference. At full frequency, It drops the temperature by approximately 20°C

I haven't had a look at the battery life yet. However, as soon as I have to travel again, I'll check this out

@ info2
Thanks for for the hints

But still, I can't set my VIDs lower than 18 :S And I'm pretty sure that my Bios is not broken...

shladnik · Post by **shladnik** » Thu Sep 06, 2007 5:40 am

Hi all,

I was using patch 0.2.9 happily, but recently i decided to upgrade kernel (linux-2.6.20-suspend2-r6 -> linux-2.6.21-suspend2-r7), so i downloed newer patch also.
I see the files:

gentoo_notes ~ # ls /sys/devices/system/cpu/cpu0/cpufreq/phc*
/sys/devices/system/cpu/cpu0/cpufreq/phc_controls /sys/devices/system/cpu/cpu0/cpufreq/phc_fids
/sys/devices/system/cpu/cpu0/cpufreq/phc_default_controls /sys/devices/system/cpu/cpu0/cpufreq/phc_version
/sys/devices/system/cpu/cpu0/cpufreq/phc_default_vids /sys/devices/system/cpu/cpu0/cpufreq/phc_vids

but i cant do anything with them:

gentoo_notes ~ # cat /sys/devices/system/cpu/cpu0/cpufreq/phc*
cat: /sys/devices/system/cpu/cpu0/cpufreq/phc_controls: No such device
cat: /sys/devices/system/cpu/cpu0/cpufreq/phc_default_controls: No such device
cat: /sys/devices/system/cpu/cpu0/cpufreq/phc_default_vids: No such device
cat: /sys/devices/system/cpu/cpu0/cpufreq/phc_fids: No such device
0.3.0
cat: /sys/devices/system/cpu/cpu0/cpufreq/phc_vids: No such device
gentoo_notes ~ # echo "16:40 14:36 12:32 10:27 8:23 6:18" > /sys/devices/system/cpu/cpu0/cpufreq/phc_controls
bash: echo: write error: No such device
gentoo_notes ~ #

I am using ondemand governor.

Thanks
Stefan

info2 · Post by **info2** » Fri Sep 07, 2007 6:39 am

Hello

shladnik:
There are some users that have this problem.
The reason is that acpi-cpufreq decides if your system is either "SYSTEM_IO_CAPABLE" or "SYSTEM_INTEL_MSR_CAPABLE". It seems that especially on older hardware acpi-cpufreq switches to the first while linux-phc need the second state.

We are currently reworking the speedstep-centrino patches. They will be released with linux-phc-0.3.1.
They will have the same sysfs interface like acpi-cpifreq so PHCtool and other userspace programs can be used with it.
Until these patches are completed you should use the 0.2x release.

If you like to test the new patches: we need you

In some few weeks the first test release will be ready.

just-linux:
Very strange.
Could you compile your kernel with cpufreq.debug enabled and send me the output of dmesg with all cpufreq messages in it (after trying to set a vid below 18, etc to have everything in it)?
Maybe i can see whats wrong.
Did it worked with the old patches and speedstep-centrino? Maybe you're also an candidate for 0.3.1.

Schmolch:
You are the first one with an lv-cpu.
It would be quite interesting to see your changes (standard-vids and lower vids, temperature difference and battery time difference, if any).
If you like you can post them here of meet me in the IRC channel of linux-phc.

Like i already wrote, we'll need people to test the coming speedstep-centrino patches once they are ready.

just-linux · Post by **just-linux** » Fri Sep 07, 2007 2:09 pm

@info2

Recently, I tried again to set a VID lower than 18 and it WORKED! I don't really know why, I haven't changed anything...

Code: Select all

tobi tobi # cat /proc/cpuinfo | grep MHz
cpu MHz         : 800.000

Code: Select all

        |     CPU 0     |     CPU 1     |
        +-------+-------+-------+-------+
        | FID   | VID   | FID   | VID   |
--------+-------+-------+-------+-------+
Min     | 6     | 18    | -     | -     |
Max     | 15    | 41    | -     | -     |
--------+-------+-------+-------+-------+
Target  | 6     | 0     | -     | -     |
Current | 6     | 0     | -     | -     |
--------+-------+-------+-------+-------+

info2 · Post by **info2** » Fri Sep 07, 2007 4:41 pm

Great news!
Maybe it's because the sun is in line with Venus and there was a mice running over a hill in Afrika.

info2 · Post by **info2** » Thu Sep 13, 2007 2:42 pm

Tester needed!

I'm proud to tell you that linux-phc-0.3.1 is nearby complete.
We just wish to test it on some different systems / processors to be sure it'll work for everybody.
Whats new?
* The speedstep-centrino patches has been reworked.
They now use the new interface acpi-cpufreq already use and is compatible with PHCtool.
* Also this patch doesn't just reject values out of range of 0.700 - 1.600Volts, it is rejecting all values above the default voltage of each step.
Accidently overvolting is now not even possible by a microvolt. Acpi-cpufreq patches already own this check.

I'll upload the developement release as soon as possible in svn.
People that want to test it now can ask for it on the irc-channel.

TheKaneB · Post by **TheKaneB** » Sat Sep 15, 2007 12:53 am

Hi!

I'm the new entry who reworked the 0.2.x patch into the 0.3.1 patch... I'm here to get any feedback directly from you.

@info2: do we know each other? ^_^

Schmolch · Post by **Schmolch** » Sat Sep 15, 2007 10:45 am

info2 wrote:Hello

Schmolch:
You are the first one with an lv-cpu.
It would be quite interesting to see your changes (standard-vids and lower vids, temperature difference and battery time difference, if any).
If you like you can post them here of meet me in the IRC channel of linux-phc.

Hi info2,

i was in the channel and we came to the conclusion that a core-duo cannot have a lower voltage then it's lowest standard voltage.

shladnik · Post by **shladnik** » Thu Sep 20, 2007 4:41 am

I can report that new patch works for me.

I used the patch from svn:
linux-phc/trunk/devel/kernel-patch/speedstep-centrino/linux-phc-0.3.1-kernel-vanilla-2.6.21.7_sc.patch

I am using kernel linux-2.6.21-suspend2-r7 (gentoo system of course) with following processor:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 1.60GHz
stepping : 6
cpu MHz : 600.000
cache size : 2048 KB

on Acer Travelmate 4000 Lmi

Stefan

info2 · Post by **info2** » Fri Sep 21, 2007 5:09 am

Thanks a lot, shladnik.
Using this new patch and the new interface you should also be able to use PHCtool.

shladnik · Post by **shladnik** » Fri Sep 21, 2007 9:04 am

Well, i can't try it right now, my system crashed...

don't know exaclty what happened. Probably something about hibernate or switching between X and console. Is there any possibility that patch would cause that? However, filesystem is corrupted (reiserfs), --rebuild-tree didn't help, so i will have to reinstall gentoo. Well, there are some files still readable. Pray for my /home and /etc.

Stefan

info2 · Post by **info2** » Fri Sep 21, 2007 11:51 am

Is there any possibility that patch would cause that?

I never heard something like that.

It is known that some programs or the whole system can crash if you undervolt too deep and put some load to the cpu.
But I never heard that the whole file system gets currupted - especially in that hard way you described.

I wish you the best.

shladnik · Post by **shladnik** » Fri Sep 21, 2007 12:25 pm

It was suspend2 probably or simply write cash of disk wasn't flushed.
For sure it wasn't undervolting too deep, since i am using this configuration for over a year without problems. And even if cpu would crash, there is probably no chance that this would affect file system.

superwutze · Post by **superwutze** » Tue Sep 25, 2007 8:59 pm

well, i have to admit that i didn't read the whole thread, so maybe i missed it, but in a quick scan i haven't read anyone mentioning the x86_64 platform.

i have a hp 6510b with an intel t7700 in a pure 64bit environment.
i patched the kernel (gentoo-2.6.22-r6) successfully but there were no options in the config menu. also i use the acpi-scaling driver right now. i now, the 64bit centrinos are pretty young, but will there be support for them?
on my last notebooks cpupw (pentium-m, 1g3) and the powernow-k8 patch (turion tl-56) worked very good and i just dislike alltime-running-fans

so far i don't even know the available frequency/voltage pairs. cpupw just fails and on vista64 rmclock doesn't work either.

info2 · Post by **info2** » Wed Sep 26, 2007 3:49 pm

Hello superwutze.

We never tried to apply those patches to a pure 64Bit system.
We would need developers and testers with 64Bit machines to maintain 64Bit patches.
Technically it >>could<< work.

TheKaneB · Post by **TheKaneB** » Thu Sep 27, 2007 6:54 pm

Hi superwutze,

as info2 said, to write a driver for your cpu we need a developer who owns that hardware. However, we are working to improve the old powernow-k8 patch for amd64 platforms, in order to be able to control every platform (centrino, core, amd64) with a generic platform-independent interface, so we can use the same tool for every machine. If anyone with good coding skills and the right hardware wants to help, please contact me or info2.

bye!

bushwakko · Post by **bushwakko** » Wed Oct 10, 2007 1:21 pm

I have a macbook pro 2.33ghz (not santa rosa) and I have undervolted in osx like this: http://generation.no/~wakko/undervolt.png and using phctool to find the same settings in linux and applying them made my laptop lock up pretty fast, so I'm thinking something isn't quite right. anyone can confirm this?

edit: I'm running 64-bit ubuntu at the moment, with the kamikaze patchset. I think they might use an old patch (2.6.22-pre1) but I'm not sure.

tnt · Post by **tnt** » Thu Oct 11, 2007 6:33 pm

hm... many core2duo users run 64bit gentoos. it would be very nice if there was some 64bit version of PHC...

tnt · Post by **tnt** » Fri Oct 12, 2007 1:48 am

btw, I've just found this great site:

http://www.lesswatts.org/

and had to share it with you...

vovin · Post by **vovin** » Sat Dec 08, 2007 8:22 pm

I tried to change voltage using patch 0.3.1 on
Linux localhost 2.6.23.9-phc #1 SMP Sat Dec 8 01:00:39 CET 2007 x86_64 Intel(R) Core(TM)2 Duo CPU E6750 @ 2.66GHz GenuineIntel GNU/Linux

It seems to detect CPU:
affected_cpus
0
cpuinfo_cur_freq
2664000
cpuinfo_max_freq
2664000
cpuinfo_min_freq
1998000
phc_controls
8:42 6:29
phc_default_controls
8:42 6:29
phc_default_vids
42 29
phc_fids
8 6
phc_version
0.3.1
phc_vids
42 29
scaling_available_frequencies
2664000 1998000
scaling_available_governors
ondemand userspace
scaling_cur_freq
2664000
scaling_driver
acpi-cpufreq
scaling_governor
userspace
scaling_max_freq
2664000
scaling_min_freq
1998000
scaling_setspeed
2664000

If I change phc_vids, there is no change in voltage and idle temperature according to gkrellm2.
If I change voltage in BIOS, I can see lower voltage and idle temperature in gkrellm2.

dixon · Post by **dixon** » Sat Jan 05, 2008 5:07 pm

I've tried out the latest linux-phc 0.3.1 running ubuntu gutsy gibbon(CPU T5470). Everything was working fine except for one thing. I cannot decrease the voltage of the lowest frequency and this frequency is the mostly used

If I change it to any lower value the phctool analysis tab gives me ->
target vid - 14
target vcc - 0.8875V
reached vid - 15
reached vcc - 0.9000V
Though lowering the voltages of other(higher) frequencies is working just fine :\

SteveBallmersChair · Post by **SteveBallmersChair** » Tue Jan 08, 2008 4:14 am

Schmolch wrote:
info2 wrote:Hello

Schmolch:
You are the first one with an lv-cpu.
It would be quite interesting to see your changes (standard-vids and lower vids, temperature difference and battery time difference, if any).
If you like you can post them here of meet me in the IRC channel of linux-phc.
Hi info2,

i was in the channel and we came to the conclusion that a core-duo cannot have a lower voltage then it's lowest standard voltage.

That is true. I have a Core 2 Duo U7500 and here's what I have:

Default (for my chip)

Speed Vcore
1067000 875 mV (VID = 13)
800000 850 mV (VID = 11)

I can set the VID for the top speed to 11 and no lower. The VID for the bottom frequency will not budge below 11. I can set it below that in phc_vids, but msrtool says that the VIDs stay anchored at 11. Also, I had to go to x86 from amd64 to get PHC to work as the patch does not work on an x86_64 kernel. I'm a little pissed, but I guess I found out what you guys wanted to know.

gesho · Post by **gesho** » Mon Jan 21, 2008 6:34 am

hi folks, thanks for your work.

now i'm runnning 2.6.23-r5, the phc-0.3.0 tarball had nothing for this one (r3 was the last). anything planned?

marcogrego · Post by **marcogrego** » Mon Mar 10, 2008 2:24 pm

hi everybody,
I am a new entry, and I happly tried phctool with GUI. I am able to set values under the "voltage" tab, but unfortunately I got a "n/a" for all the columns for the "Analysis" tab. Which makes me think my system is not correctly recognized (?).
My aim is just checking whether the undervolting I am doing is applied.
I also did patch the acpi-cpufreq kernel module and recompiled a custom kernel excluding the deprecated speedstep-centrino. (my kernel: 2.6.22)
Any advice?

Thank you in advance!

--
Marco

SteveBallmersChair · Post by **SteveBallmersChair** » Tue Mar 11, 2008 1:10 pm

marcogrego wrote:hi everybody,
I am a new entry, and I happly tried phctool with GUI. I am able to set values under the "voltage" tab, but unfortunately I got a "n/a" for all the columns for the "Analysis" tab. Which makes me think my system is not correctly recognized (?).
My aim is just checking whether the undervolting I am doing is applied.
I also did patch the acpi-cpufreq kernel module and recompiled a custom kernel excluding the deprecated speedstep-centrino. (my kernel: 2.6.22)
Any advice?

Thank you in advance!

--
Marco

You need to load the model-specific registers (MSR) module:

sudo modprobe msr

Then put it in /etc/modules.autoload.d/kernel-2.6 so that it gets loaded in the future automatically.

user undervolting

Patch 0.3 not working

New patch works for me

Can't try

undervolting through phctool

Re: undervolting through phctool