High Idle CPU temperature under Ubuntu, but not Windows

Question

I have a Dell Inspiron Mini 1012 running Ubuntu 10.04 and Windows 7 Starter in a dual-boot configuration.

The CPU runs much cooler in Windows than it does in Ubuntu, even when the CPU has been idling. For example, I'm in Ubuntu now, the CPU has been idling for some time, and the CPU temperature is 72 C according to lm-sensors and coretemp.

The machine actually overheated in Ubuntu at one point, just from running the CPU at 100% for an extended period of time. Again, this problem only occurs in Ubuntu - I have never noticed a heat issue in Windows.

I have tried using the CPU Frequency Scaling Monitor GNOME applet to set my CPU speed to 1GHz (instead of 1.67GHz) and Powersave mode, but this does not seem to affect the idle temperature.

Here is /proc/cpuinfo:

processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 28
model name  : Intel(R) Atom(TM) CPU N450   @ 1.66GHz
stepping    : 10
cpu MHz     : 1000.000
cache size  : 512 KB
physical id : 0
siblings    : 2
core id     : 0
cpu cores   : 1
apicid      : 0
initial apicid  : 0
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 10
wp      : yes
flags       : fpu vme de tsc msr pae mce cx8 apic mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm
bogomips    : 3325.06
clflush size    : 64
cache_alignment : 64
address sizes   : 32 bits physical, 48 bits virtual
power management:

processor   : 1
vendor_id   : GenuineIntel
cpu family  : 6
model       : 28
model name  : Intel(R) Atom(TM) CPU N450   @ 1.66GHz
stepping    : 10
cpu MHz     : 1000.000
cache size  : 512 KB
physical id : 0
siblings    : 2
core id     : 0
cpu cores   : 1
apicid      : 1
initial apicid  : 1
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 10
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm
bogomips    : 3325.07
clflush size    : 64
cache_alignment : 64
address sizes   : 32 bits physical, 48 bits virtual
power management:

Does anyone have any advice as to how I can get my CPU to run cooler under Ubuntu?

Update:

Here is the output of powertop, after running it for about a minute:

Cn                Avg residency       P-states (frequencies)
C0 (cpu running)        (13.7%)         1.67 Ghz     2.8%
C0                0.2ms ( 0.0%)         1333 Mhz     0.3%
C1 mwait          0.3ms ( 2.2%)         1000 Mhz    96.9%
C2 mwait          0.5ms (14.2%)
C4 mwait          0.8ms (69.9%)


Wakeups-from-idle per second : 1303.9   interval: 10.0s

Power usage (ACPI estimate): 13.3W (2.7 hours)

Top causes for wakeups:
  33.4% (611.7)   chromium-browse
  26.5% (483.7)   PS/2 keyboard/mouse/touchpad interrupt
  17.7% (324.3)   [extra timer interrupt]
   7.8% (142.9)   [kernel scheduler] Load balancing tick
   2.3% ( 41.2)   ekiga
   1.9% ( 34.0)   [eth1] 
   1.6% ( 29.4)   rhythmbox
   1.3% ( 24.5)   USB device  1-8 : USB2.0-CRW (Generic)
   1.3% ( 24.2)   Xorg
   1.1% ( 19.8)   desktopcouch-se
   1.0% ( 18.5)   [ehci_hcd:usb1, uhci_hcd:usb2] 
   0.8% ( 15.5)   [acpi] 
   0.6% ( 10.8)   [kernel core] hrtimer_start (tick_sched_timer)
   0.4% (  6.9)   [kernel core] add_timer (wl_timer)
   0.3% (  5.3)   parcellite
   0.2% (  3.6)   gwibber-service
   0.2% (  3.0)   [Rescheduling interrupts] 
   0.2% (  3.0)   wpa_supplicant
   0.1% (  2.3)   python
   0.1% (  2.3)   gnome-terminal
   0.1% (  2.1)   beam.smp
   0.1% (  1.9)   multiload-apple
   0.1% (  1.8)   NetworkManager

Update:

Upgrading to kernel 2.6.38-1 via PPA actually seems to make the wakeups-per-second as bad or worse:

PowerTOP version 1.12      (C) 2007 Intel Corporation                                                                            

Cn                Avg residency       P-states (frequencies)
C0 (cpu running)        (13.2%)         1.67 Ghz     9.6%
polling           0.0ms ( 0.0%)         1333 Mhz     1.1%
C1 mwait          0.5ms ( 4.2%)         1000 Mhz    89.3%
C2 mwait          0.7ms (50.8%)
C4 mwait          0.5ms (31.8%)

Wakeups-from-idle per second : 1465.2   interval: 10.0s                                                                                                                   
Power usage (ACPI estimate): 13.5W (3.6 hours) (long term: 12.6W,/3.9h)

Top causes for wakeups:
  35.8% (483.6)   PS/2 keyboard/mouse/touchpad interrupt
  27.0% (364.4)   chromium-browse
  21.0% (284.5)   [extra timer interrupt]
   2.7% ( 36.0)   kworker/0:0
   2.5% ( 34.3)   [kernel scheduler] Load balancing tick
   2.5% ( 33.8)   Xorg
   1.5% ( 19.9)   desktopcouch-se
   1.1% ( 15.1)   [acpi] 
   0.0% (  0.1)D  flush-8:0
   0.9% ( 12.5)   USB device  1-8 : USB2.0-CRW (Generic)
   0.9% ( 12.0)   [ehci_hcd:usb1, uhci_hcd:usb2] 
   0.1% (  0.7)D  upowerd
   0.6% (  8.3)   parcellite
   0.5% (  7.3)   [ahci] 
   0.5% (  6.1)   gnome-terminal
   0.3% (  3.6)   gwibber-service
   0.2% (  3.0)   [kernel core] timer_action (ehci_watchdog)
   0.2% (  2.8)   [kernel core] hrtimer_start (tick_sched_timer)
   0.2% (  2.2)   python
   0.1% (  2.0)   multiload-apple
   0.1% (  2.0)   beam.smp
   0.1% (  1.7)   [Rescheduling interrupts] 
   0.1% (  1.6)   [eth0] 

The program 'upowerd' is writing to file 'history-rate-DELL_2T6K207N-52.d' on `/dev/sda5`. This prevents the disk from going to powersave mode.

 Q - Quit   R - Refresh  
0$ notes  1$ todo  2$ dev1  3$ dev2  4$ dev3  5$ srv  (6*$bash)  7-$ bash                                                                                    05/26  2:03PM

Solution 1

It is not really an anwser more a proposal how to proceed. For me it seems impossible that a CPU that is idling should produce a heat of 72 degree celcius. Do you mean by idling on the os is running or did you check the load of the CPU?

Install powertop from synaptics and start the programm in the terminal by "sudo powertop" the programm will tell what the CPU is really doing. It tells you also which activities keeps the CPU busy.

Solution 2

Install jupiter, either jupiter or acpi=off, it completely stopped my power hogging problem.

acpi= off stopped most of it but with jupiter installed it has never come back. The freq scaling applets don't always stay on the panel for me.

Solution 3

Have you checked your CPU Frequency?

Usually my laptop only heats up when the frequency is higher than normal for extended periods.

You can control the frequency by adding the "cpu frequency applet" to the panel (if you are using gnome).

Comments

[theTuxRacer]

Can you post the version no. of you kernel, by pasting the output of uname -r in your question?

[jbeard4]

It's the stock, up-to-date 10.04 kernel: 2.6.32-31-generic

[Andrew Gunnerson]

Even with a few browsers and IDE's open, my CPU wakeups never exceed 600. Also, even running my Core 2 Duo at 100% for over an hour, the temperature won't reach 72 C. I'm thinking it's a kernel issue. Try installing kernel 2.6.34 from the Ubuntu kernel PPA: kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.34-lucid

[jbeard4]

Chen, that's a good point of reference, thank you. I'll try upgrading the kernel via PPA - or I might just bite the bullet and try to dist-upgrade to Natty.

[vanjadjurdjevic]

Try my solution and let me know if it works. It seems that we have the same problem <br/>

[jbeard4]

I checked the CPU load using top. I also have the system monitor applet which shows me a graph of the CPU load over time. By "idle" I mean that the CPU load is very low or is none.

[Luke]

This seems quite normal. How is your fan behaving? Some laptops/netbooks have fancontrol problems under ubuntu. The attached link should allow you to read out your sensors. May be you have a dedicated sensor for the fan. zefanjas.de/2008/12/03/cpu-temperatur-lufterdrehzahlen-etc-m‌​it-ubuntu-auslesen/

[jbeard4]

It's fanless: notebookcheck.net/Review-Dell-Mini-1012-Netbook.25429.0.html

[jbeard4]

The temperatures listed at the link I posted are consistent with my own experience. It stays cool on idle while in Windows.

[Luke]

Sorry I am out of ideas. You are measuring the temp of the cpu. Even if you have another heat producer (GPU) it shouldn't influence the cpu temp but only the overall temp. Did you measure the temp in windows under a similar cpu load? upgrade to 11.04 to see if different kernel produce the same result?

[Luke]

I read that your netbook should be good for 6 plus workinghours. The reading of powertop shows 2.7 hours remaining. What is the capacity of your battery? How much working hours do you get in W7 and Ubuntu. If its much less in Ubuntu it means higher consumption which should translate to temperature.

[jbeard4]

As stated in the question, I have tried using the CPU Frequency Scaling Monitor GNOME applet to set my CPU speed to 1Ghz (instead of 1.67Ghz) and Powersave mode, but this does not seem to affect the idle temperature.

[jbeard4]

Thanks for the reply. I'm using a stock kernel, and the machine is fanless.

[Eric Carvalho]

Welcome to Ask Ubuntu! Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference.