Ubuntu – High CPU Frequency at Idle

14.10cpufreq

I've recently installed indicator-multiload on my laptop running Ubuntu 14.10 and noticed my CPU sits most of the time at high frequencies, even with very little load. It is an i7-4700MQ processor which should use frequencies between 800 MHz and 3.4 GHz (with Turbo Boost). Now even when load is 0-2%, the frequencies I see are usually between 2.5 and 3.1 GHz, which means the CPU is almost always Turbo Boosting.

My Ubuntu also uses significantly more power than Windows (where the CPU is often in the 0.8 – 1.8 GHz range) with little load, so I'm thinking it's not just a wrongly displayed frequency.

I haven't manually changed any setting or installed anything that should affect the CPU behaviour. Below is the content of my cpufreq and intel_pstate, which looks right to me:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver 
intel_pstate
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq 
800000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 
3400000
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq 
2852437

$ cat /sys/devices/system/cpu/intel_pstate/min_perf_pct 
23
$ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct 
100    
$ cat /sys/devices/system/cpu/intel_pstate/no_turbo 
0

Has anyone seen this before or knows how to avoid using high frequencies for no reason?

Just to mention, I know Turbo Boost can be disabled, which would probably limit the max frequency to 2.4 GHz, but that seems like overkill, since I don't want to limit my CPU performance when I need it.

Thank you.

EDIT: The scaling governor is set to powersave:

$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
powersave
powersave
powersave
powersave
powersave
powersave
powersave
powersave

These are the frequencies:

$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq
2492343
2740218
2502562
2438625
2435718
2782500
2783250
2697000

Nothing is using my CPU. As I said, usage is at about 1%. If I run top, it is the only running user process:

Tasks: 266 total,   1 running, 265 sleeping,   0 stopped,   0 zombie
%Cpu(s):  1.3 us,  0.2 sy,  0.0 ni, 98.5 id

Best Answer

After more looking around, I've found two relevant issues on the kernel bugtracker that describe the same symptoms I'm experiencing. This one is marked as fixed, but this other one is new, with people reporting it's not yet fixed.

There seems to be something going on with putting the computer to sleep. The CPU runs normally, i.e. at low frequencies while idle, just after a reboot, but is stuck to high frequencies after waking up from sleep. After a fresh reboot, my frequencies looks like this (compare to what's posted in the question):

$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq
1588875
800062
800062
800062
928500
2112937
800250
1911750

I guess for now we just have to wait until this is fixed.

Answer Version 3.0

Kernel version 4.14.98 has finally fixed problems I've noticed for last 6 months or so:

When system is idle CPU frequency would spike to 3,000 MHz in Turbo Mode.
When system is busy CPU frequency would simmer down to about 1,500 MHz.

Now as you can see when system is idle system is at 800 MHz as it should be:

Answer Version 2.0

OP updated question with results of Initial Answer below and for whatever reason the governor is set to performance mode which runs all CPU's at max speed all the time.

We need to do the reverse of this answer: Set CPU governor to performance in 18.04:

Use: sudo -H gedit /etc/rc.local put insert this before the last line containing exit 0:

sleep 120 # Give CPU startup routines time to settle.
echo powersave | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
echo 800000 | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq

Save the file and reboot. Two minutes after rebooting your CPU's will settle down and run normally.

What if `/etc/rc.local` doesn't exist?

From this: Ubuntu 16.10 rc.local file does not exist

you need to enter:

sudo systemctl enable rc-local.service

Initial Answer

According to: intel_pstate CPU Performance Scaling Driver, intel_pstate status should be:

status

Operation mode of the driver: “active”, “passive” or “off”.

“active”
    The driver is functional and in the active mode.
“passive”
    The driver is functional and in the passive mode.
“off”
    The driver is not functional (it is not registered as a scaling driver with the CPUFreq core)

My first step would be to remove your kernel command line parameter intel_pstate=disable.

Reboot and type the following:

$ cd /sys/devices/system/cpu/cpu0/cpufreq

$ paste <(ls *) <(cat *)

affected_cpus                             0
cpuinfo_max_freq                          3500000
cpuinfo_min_freq                          800000
cpuinfo_transition_latency                0
energy_performance_available_preferences  default performance balance_performance balance_power power 
energy_performance_preference             balance_performance
related_cpus                              0
scaling_available_governors               performance powersave
scaling_cur_freq                          832522
scaling_driver                            intel_pstate
scaling_governor                          powersave
scaling_max_freq                          3500000
scaling_min_freq                          800000
scaling_setspeed                          <unsupported>

This is what I have in a default configuration without intel_pstate=disable.

Pay close attention to scaling_max_freq and scaling_min_freq.

You might want to temporarily uninstall CPU Freq Utils package:

sudo apt remove cpufrequtils

I have never found a need for it and it might be mucking your system up. Later you can install it again (if need be) with:

sudo apt install cpufrequtils

Best Answer

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Answer Version 3.0

Answer Version 2.0

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