Intel p_state not scaling cpu frequency properly on Intel I7 4720HQ

borgilian · 2015-09-01 10:43:23

Hi ! I'm new here so I'm sorry if I don't provide every detail possible . I've been searching for a solution to my problem for a few days now and I cannot seem to find one . The problem goes like this :

I'm dual booting windows 8.1 and Arch linux on a Clevo P650SE laptop . On windows I've noticed (after disabling turbo boost and enabling balanced power settings) that my CPU idle temperature is around 40-42 C with highest being 55 C on firefox while watching 1080p60fps videos on youtube (chrome heats it up to around 64 C ). CPU gets to 55 C under 12-16 % load at 1.2 Ghz reported by task manager with 1080p60fps and goes down to 42 C while browsing at 800 Mhz - 1 Ghz frequency .

My HDD temperature stays around 38 C with firefox with 5-6 tabs open and only goes to 41-42 C under heavy load . I obtain these temperatures under windows with an ambiental temperature of 31 C (really annoying hot summer) .

Now my problem is that my laptop gets hot as soon as I boot into arch : 45 C cpu idle temperature at 2.6 ghz most of the time , rarely going to 1.4 Ghz or the minimum 800 Mhz . Doing some browsing and checking my email heats up my cpu to around 50-51 C . My HDD sits at 40 C idling and I can feel it warm when I put my hand where it is located ... something that barely happens under windows .I've tried adjusting power management for the HDD with hdparm , but with no luck .
Watching 1080p60fps videos get my CPU to around 65 C . The fans don't have dust on them and are functioning properly . It's obviously a problem with the scaling governor jumping the frequency close to maximum even on 1% load (I had to limit my maximum frequency to 2 GHz to get at least 44 C while browsing and it's mostly sitting at 1800 MHz ) . Also , I cannot disable turbo boost with echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo , permission denied as sudo. Surprisingly , the CPU is in the C7 state most of the time while idling , but still with high frequency .

Temperature and cpu frequency were monitored with i7z-git . TLP and thermald are enabled and bumblebeed service is also enabled in order to disable the discrete GPU . The high frequency problem while idle is present in both Gnome (which I'm using currently) and while in the console after I've exited gnome (also tested at boot without entering gnome).

I've read on some other threads that there might be a bug with the intel pstate driver and haswell cpu's concerning the 300 hz kernel timing frequency in arch . One solution that some reported it's working is changing the timing frequency to 250 hz or 1000hz , but I have no idea how to do that (never done a kernel compile and config) . Another is disabling pstate driver at boot command line and using the old driver ... which would be a last solution for me , even if it's not properly using the CPU .

Sorry for my long post and thanks for reading !

Last edited by borgilian (2015-09-01 10:46:34)

graysky · 2015-09-01 11:25:59

https://bugzilla.kernel.org/show_bug.cgi?id=93521

?

borgilian · 2015-09-01 11:40:17

graysky wrote:

https://bugzilla.kernel.org/show_bug.cgi?id=93521
?

Yep , I believe it's the same bug and it behaves the same , except that for me the frequency is still high even without xorg running . Also read that bug report but I forgot to mention it .

I've disabled the pstate driver now and I'm getting proper frequency scaling with ondemand governor . Temperatures are almost as good as in windows now and I barely hit 60 C on chrome on 1080p60fps .

ALSO , forgot to mention I'm using kernel 4.1.6-1 .

Last edited by borgilian (2015-09-01 11:46:13)

graysky · 2015-09-01 12:06:08

I find on my i7-4790K that increasing the tick rate from 300 to 1000 helps. More here: https://bbs.archlinux.org/viewtopic.php?id=193983

EDIT: you can test for yourself

1) Install i7z from [community]
2) Run it with nothing open, no screensaver actives, from your desktop in X like this `sudo i7z -w a -l arch-300Hz`
3) Wait 5 min or so to get a good log file
4) Stop it via `ctrl+c` and run the following script on the logfile which will show you the median frequency from the run: https://gist.github.com/graysky2/28e69f48ee33f01d14f8
5) Rebuild the kernel enabling 1000 Hz ticks, reboot into it, and repeat using a different logfile name, `sudo i7z -w a -l arch-1000Hz`
6) Post the median values for the stock 300 Hz and the modified 1000 Hz.

Last edited by graysky (2015-09-01 12:13:00)

Arch Linux

#1 2015-09-01 10:43:23

Intel p_state not scaling cpu frequency properly on Intel I7 4720HQ

#2 2015-09-01 11:25:59

Re: Intel p_state not scaling cpu frequency properly on Intel I7 4720HQ

#3 2015-09-01 11:40:17

Re: Intel p_state not scaling cpu frequency properly on Intel I7 4720HQ

#4 2015-09-01 12:06:08

Re: Intel p_state not scaling cpu frequency properly on Intel I7 4720HQ

Board footer