i7-3740QM, pstate, powersave and overheating

gryf · n00b Joined: 09 Jun 2004 Posts: 50

So, I've spent a quite some time on trying to prevent my laptop from burning entire city.

The actors:

- Dell Latitude E6430 with i7-3740QM CPU
- Gentoo (obviously) with kernel 4.14.x
- Debian testing with kernels 4.16.x

I've noticed some time ago, that this laptop tends to go beyond usual temperatures, even for this particular processor, which have working temperature pretty high. But lately, I've started to have ~60°C at idle and in stress over 98-102°C which is almost at the upper limit for this cpu. I didn't joined the dots than, but now I think all that madness begins with 4.x kernel line.

I've started with cleaning cooling system and replacing thermal paste with the fresh one, which helps for some time, but temperatures always back to ~60-70°C at idle.

Than, I've decided to replace this laptop with another one, which I have from work, removed hard drive and forgot about the issue.

Lately I have dig it up again, put the spare hard drive and installed Debian testing, since I needed a machine for a certain task. I was so surprising that temperatures was around 48-52°C at idle and the fan was not trying to replace my hair dryer…

So I've started to investigate. First of all, I've checked up what drivers are used for frequency and idle control, installed `i7z` and `cpupower` for measurements, and trying to find anything useful on the internet. I found several threads regarding pstate and frequency, but all of the hints I could find there doesn't solve the issue. Conclusion was, that on Debian there is almost fanless idle with frequency ~1.2GHz and temperatures around 55°C, while on Gentoo I have on idle crazy and noisy fan, ~70°C and ~3,6GHz most the time (with some drops to 3.2GHz but, temperature was constant).

Finally, I've cloned my working Gentoo system and made dual-boot with Debian for investigating purposes on this machine. And using this[1] thread, and Debian prepared the kernel config hoping for less heat.

Here is my kernel conf on Gentoo:

duane · Posted: Wed Jul 04, 2018 5:39 am Post subject:

I'd like to hear more about this if you find out anything. I had trouble getting my little acer e15 with an i5 processor to run cool at first, but setting p-state on seemed to cure it. My config looks basically like yours except that I don't have anything in modules and I'm still on the 4.9 kernel.

Pearlseattle · Posted: Thu Jul 05, 2018 10:50 pm Post subject:

Could you please post the output of "lspci -k"?
I'm curious to see if you have a discrete GPU.

About P-state mentioned by "duane":
I experienced both sides: some CPUs worked perfectly with P-state, for others it was absolutely terrible.
Maybe you could post here as well the output of "cat /proc/cpuinfo | grep -i "model name""?

Cheers

duane · Posted: Fri Jul 06, 2018 12:17 am Post subject:

krinn · Watchman Joined: 02 May 2003 Posts: 7470

your kernel is default set to use CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
you are also using intel_pstate :
#1 intel_pstate default is performance governor
#2 intel_pstate governors are only "performance" or "powersave", powersave should act like ondemand, so if you want ondemand governor using intel_pstate, you must set the governor to "powsersave"

try that:

gryf · n00b Joined: 09 Jun 2004 Posts: 50

Ok, here is another portion of my findings.

Yesterday I was experiment with Xorg, since I've seen i915 near top of powertop, and switch X off completely just to have clear sight (although on Debian all measures I've done with X running). I discovered, that on bare system i7z readings are similar to the Debian ones, so multiplier is set firmly in 12x, frequency is around 1.2GHz and is stable (no fluctuation at all) and VCore is around 0.95V but temperature is like ~64°C (still higher than on Debian around 10°C)

I've launch Xorg again and kill all dockapps (I'm using wmaker, as wrote in original post), which I usually have, and than run them one by one. Quickly turns out that one of them was responsible for waking processor to often, and as the result, makes processor constantly switching to higher freq and voltage. For the record, this dockapp is x11-plugins/wmhdplop. I've removed it from my desktop.

Still, I thing I'm missing something, which I cannot track down - in Debian I still have 10°C less than on Gentoo, and pstate switching is more aggressive than in Debian. I'm still trying to figure out how to bring down the temperature for at least 10°C.

duane · Posted: Fri Jul 06, 2018 8:17 pm Post subject:

Have you tried PM_AUTOSLEEP, or PCIEASPM_POWERSAVE? Just shooting in the dark.

gryf · n00b Joined: 09 Jun 2004 Posts: 50

As a workaround, I currently disabled turbo boost, and gained ~5°C. I'm wondering if this can be a subject to take into account by governors.

mociofiletto · n00b Joined: 20 Mar 2004 Posts: 8

Hi, I am experiencing the same issue with an Intel(R) Core(TM) i7-4700HQ CPU @ 2.40GHz.
After a few minutes after gentoo is started, the fan speed goes to max (4200rpm) and the CPU temperature arises to around 90°C
I have installed thermald and but it seems to be unuseful

The default scaling governor is "performance" and the scaling driver is "intel_pstate"
The situation is as follows:

mociofiletto · n00b Joined: 20 Mar 2004 Posts: 8

Now I tested 4.9.95 using "ondemand" as default governor.
The system uses powersave as governor and intel_pstate as scaling driver, but the temperature is always too high as with 4.14 kernel:

mociofiletto · n00b Joined: 20 Mar 2004 Posts: 8

I think the problem is intel_pstate always keeps CPU at its max frequency.
The temporary solution is to limit it to something that doesn't create overheating.
This is what I have done:

sao98021 · Posted: Sat Jul 28, 2018 4:44 pm Post subject:

i have a asus k53sv, intel i72670qm nvidia g540m bumblebee setup, i recently jumped up to 4.17 because i read about all the power savings changes like "some devices will get up to 10% more performance"

i like it, idles between 34-39c and all cpu cores drop to around 760-800, i do use p_state

if your interested https://pastebin.com/mFKteXR9 is the kernel config i'm using, it could get cleaned up alot as it's just a modified genkernel config

also, i see that some models of that laptop come with the optimus discrete gpu "we also advise that you pay an extra $99 for the Nvidia NVS 5200M discrete graphics chip."

i'm assuming your positive that your model does not, but may want to check if not.

n05ph3r42 · Tux's lil' helper Joined: 11 Jul 2016 Posts: 135

I can also recommend to force powersave manager( disable all the rest in your kernel) + install thermald. Recently i added new info about it to power management r page: Also, for Intel processors used in laptops since 2011 you may want to enable

BTW as for nouveau - it forces higher voltage for GPU since about a year or two => it leads to + ~10c to CPU temp (one cooling chassis on my laptop, i DIY modified it, but it does a lil' - i already upgraded CPU which is 10TDP higher than designed) so i disabled NV GPU at all.

mrgomm · n00b Joined: 15 Jul 2019 Posts: 1

I found this thread trying to solve a problem very similar for my laptop, (I own one with the same CPU BTW), the fan was driving me nuts since I installed Gentoo, I thought I followed all the guides and always it was the same, the sensor "Other" (I'm still not sure where it is in the motherboard, but I think it's close to the RAM and the wifi card) was around 10ºC hotter in Gentoo than Ubuntu, just enough to get the fan noisy all the time. I just registered to say that in my case, after much digging, the solution came by using powertop and enabling all the optimizations at boot (just disabling after that a port, corresponding to my USB mouse).

I achieved that by creating a file callled /etc/local.d/powertop.start and there inside: