CPU runs at high speed after upgrade

[Shevek]

After a dist-upgrade from 15.04 to 15.10, moving from kernel 3.19.0-43 to 4.2.0-23, my laptop CPU runs continuously at 3GHz, and never slows down to 800MHz, as it used to. This has reduced my battery life from 24 hours to 8 hours.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: linux-image-4.2.0-23-generic 4.2.0-23.28
ProcVersionSignature: Ubuntu 4.2.0-23.28-generic 4.2.6
Uname: Linux 4.2.0-23-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: shevek 2664 F.... pulseaudio
 /dev/snd/controlC0: shevek 2664 F.... pulseaudio
CurrentDesktop: XFCE
Date: Mon Jan 18 11:38:29 2016
HibernationDevice: RESUME=UUID=22fd2208-7557-432d-bbff-95dd97905323
InstallationDate: Installed on 2015-05-18 (244 days ago)
InstallationMedia: Xubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422.1)
MachineType: LENOVO 20CKCT01WW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.2.0-23-generic.efi.signed root=/dev/mapper/xubuntu--vg-root ro noprompt persistent quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.2.0-23-generic N/A
 linux-backports-modules-4.2.0-23-generic N/A
 linux-firmware 1.149.3
SourcePackage: linux
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: Upgraded to wily on 2016-01-17 (1 days ago)
dmi.bios.date: 08/20/2015
dmi.bios.vendor: LENOVO
dmi.bios.version: N11ET34W (1.10 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20CKCT01WW
dmi.board.vendor: LENOVO
dmi.board.version: 0B98417 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN11ET34W(1.10):bd08/20/2015:svnLENOVO:pn20CKCT01WW:pvrThinkPadT550:rvnLENOVO:rn20CKCT01WW:rvr0B98417WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.name: 20CKCT01WW
dmi.product.version: ThinkPad T550
dmi.sys.vendor: LENOVO

[Shevek (r-launchpad-anarres-org)]

Note, it's not continuously at max speed, it's varying between 2.9GHz and 3.2GHz. But it never slows down. My load average is very low.

[Shevek (r-launchpad-anarres-org)]

Also related?
https://bugzilla.kernel.org/show_bug.cgi?id=90421
https://askubuntu.com/questions/582805/high-cpu-frequency-at-idle

Workaround from that bug: Force low power state:

shevek@raven:/sys/devices/system/cpu/intel_pstate$ cpupower frequency-info
analyzing CPU 0:
  driver: intel_pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 0.97 ms.
  hardware limits: 500 MHz - 3.20 GHz
  available cpufreq governors: performance, powersave
  current policy: frequency should be within 500 MHz and 2.80 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency is 3.19 GHz.
  boost state support:
    Supported: yes
    Active: yes
shevek@raven:/sys/devices/system/cpu/intel_pstate$ sudo cpupower frequency-set -g powersave
Setting cpu: 0
Setting cpu: 1
Setting cpu: 2
Setting cpu: 3
shevek@raven:/sys/devices/system/cpu/intel_pstate$ cpupower frequency-info
analyzing CPU 0:
  driver: intel_pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 0.97 ms.
  hardware limits: 500 MHz - 3.20 GHz
  available cpufreq governors: performance, powersave
  current policy: frequency should be within 500 MHz and 2.80 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency is 1.20 GHz.
  boost state support:
    Supported: yes
    Active: yes
shevek@raven:/sys/devices/system/cpu/intel_pstate$ grep MHz /proc/cpuinfo
cpu MHz : 1300.000
cpu MHz : 1405.726
cpu MHz : 1200.062
cpu MHz : 1229.617

Now it's scaled down again.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Shevek (r-launchpad-anarres-org)]

Still exists in 4.2.0-25-generic
Almost no time is spent in power state C0. Battery life down to as little as 3 hours from previous 20+.

[Shevek (r-launchpad-anarres-org)]

Tried switching to 3.19 kernel - still high speed.
Tried switching to intel X driver instead of modesetting: CPU still runs at high speed.

The only changes I haven't backed out are:
a) The Ubuntu 15.10 userland.
b) The BIOS update from 1.07 to 1.10.

With absolutely quiescent system, under modesetting driver, CPU will settle at 800MHz, but wiggling the mouse or outputting to an xterm causes the CPU speed to rise. Under intel driver, an apparently absolutely quiescent system seems to use more CPU than under modesetting.

powertop is reporting power usage between 12 and 26 W, whereas previously with 15.04 I had power usage of 5-8W.

Please help, this is killing me. No battery = no computer.

[Shevek (r-launchpad-anarres-org)]

The following things do NOT seem to have any effect:
* Rebooting from cold.
* Suspending and resuming
* Plugging in or removing external power.

BIOS settings are for battery optimized, balanced performance. Everything is as expected.

[Shevek (r-launchpad-anarres-org)]

It "feels" as if the system is just too aggressive at ramping up CPU speed in response to demand? Is this a tuneable parameter? Really, for a desktop, something should be on a run queue for a couple of dozen ms before speed ramps up, and with a loadavg of close to zero, that shouldn't move the needle on this system?

[Shevek (r-launchpad-anarres-org)]

This is powertop.

Power est. Usage Events/s Category Description
  8.11 W 100.0% Device Radio device: thinkpad_acpi
  382 mW 2.6 ms/s 55.3 Process xfwm4 --replace --display :0.0 --sm-client-id 2fcff95f2-164a-40f4-87bf-49f188175134
  207 mW 100.0% Device USB device: usb-device-138a-0017
  194 mW 17.1 ms/s 78.0 Process /usr/lib/x86_64-linux-gnu/xfce4/panel/wrapper-2.0 /usr/lib/x86_64-linux-gnu/xfce4/pa
  177 mW 15.6 ms/s 57.0 Process python3 /opt/scudcloud/scudcloud
  167 mW 100.0% Device USB device: MultiTouch Sensor (Wacom Co.,Ltd. )
  165 mW 11.4 ms/s 60.2 Process /usr/lib/x86_64-linux-gnu/indicator-application/indicator-application-service
  159 mW 13.6 ms/s 33.7 Process /usr/lib/firefox/firefox

The unnamed usb device is the fingerprint reader, which I am not using and do not have a driver for. Soft-blocking wifi and/or bluetooth does not reduce the 8.11W used by thinkpad_acpi, and anyway, i'm somewhat suspicious of that assignment of power consumption.

This is cpupower monitor:
    |Nehalem || Mperf || Idle_Stats
CPU | C3 | C6 | PC3 | PC6 || C0 | Cx | Freq || POLL | C1-B | C1E- | C3-B | C6-B | C7s- | C8-B | C9-B | C10-
   0| 1.13| 1.22| 0.00| 0.00|| 8.71| 91.29| 884|| 0.00| 0.60| 0.52| 1.03| 0.79| 4.49| 12.19| 55.25| 16.50
   1| 1.13| 1.22| 0.00| 0.00|| 7.36| 92.64| 864|| 0.00| 0.13| 3.04| 0.51| 0.65| 1.91| 17.36| 43.86| 25.20
   2| 0.34| 1.07| 0.00| 0.00|| 6.53| 93.47| 885|| 0.00| 0.04| 0.54| 0.58| 1.18| 1.85| 6.01| 59.26| 24.08
   3| 0.34| 1.07| 0.00| 0.00|| 4.92| 95.08| 871|| 0.00| 0.06| 1.93| 0.08| 0.05| 0.99| 6.44| 69.57| 16.00

I don't know how to parse this.

[Shevek (r-launchpad-anarres-org)]

More powertop. It's clearly misreporting, and I'm fairly sure the outstanding power must be going into the CPU, as that's the part of the system that's physically hot to the touch.

Power est. Usage Events/s Category Description
  4.21 W 15.2% Device Display backlight
  2.32 W 100.0% Device Radio device: thinkpad_acpi
  1.58 W 100.0% Device USB device: usb-device-138a-0017
  523 mW 10.5 pkts/s Device Network interface: wlan0 (iwlwifi)
  278 mW 32.9 ms/s 18.4 Process /usr/lib/thunderbird/thunderbird

Also, this data implies that my backlight has a maximum power of 28 watts, which is false. It's about 5, measured on a nonbroken kernel/bios/driver-set.

[Shevek (r-launchpad-anarres-org)]

i7z: It never gets down to C3 or below, and presumably never enters a high P-state.

  Real Current Frequency 2702.85 MHz [99.73 x 27.10] (Max of below)
        Core [core-id] :Actual Freq (Mult.) C0% Halt(C1)% C3 % C6 % Temp VCore
        Core 1 [0]: 2676.54 (26.84x) 18.5 78.7 1.2 1 43 0.7717
        Core 2 [2]: 2702.85 (27.10x) 13.3 81.8 2.32 2.01 43 0.7726

[Shevek (r-launchpad-anarres-org)]

Same results in mainline 4.4 kernel. Clock speed almost never drops below 2.6GHz. I want it to idle at 800MHz when I'm not doing anything much.

[penalvch (penalvch)]

Shevek, to see if this is already resolved upstream, could you please test the latest mainline kernel (4.5-rc1) and advise to the results?