[Bug 536435] [NEW] scaling_max_freq is cut upon system load

[Thomas]

Public bug reported:

Magically the maximum available scaling frequency (scaling_max_freq) is throttled to the half of the maximum once the cpu usage goes high and the system response gets quite slow.
I don't know which daemon or kernel module is currently responsible to adjust the cpu frequencies. I already tried to turn on debug output via cpufreq.debug=7 as a boot parameter but this did not help either. Probably the debug option is not compiled in.
The cpu I use is an Intel T7700  @ 2.40GHz, sitting in a laptop T61p.
I do not believe it is related to some temperature because it is quite low at 49 degrees. Further more the scaling is reduced nearly instant related to the cpu usage.

ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
   Subdevices: 2/2
   Subdevice #0: subdevice #0
   Subdevice #1: subdevice #1
AudioDevicesInUse:
 USER        PID ACCESS COMMAND
 /dev/snd/controlC0:  th         1902 F.... pulseaudio
                      th         1922 F.... kmix
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xfe220000 irq 17'
   Mixer name	: 'Analog Devices AD1984'
   Components	: 'HDA:11d41984,17aa20bb,00100400'
   Controls      : 29
   Simple ctrls  : 18
Date: Wed Mar 10 13:06:55 2010
DistroRelease: Ubuntu 10.04
HibernationDevice: RESUME=UUID=1ced2f20-5b24-4186-b724-525da134cf99
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Alpha i386 (20100308)
MachineType: LENOVO 6459CTO
NonfreeKernelModules: nvidia
Package: linux-image-2.6.32-16-generic-pae 2.6.32-16.25
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-16-generic-pae root=UUID=c66cd5e2-e31e-4e8e-a5e0-615d3c1dd5bc ro quiet splash cpufreq.debug=7
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=en_US.utf8
 SHELL=/usr/bin/zsh
ProcVersionSignature: Ubuntu 2.6.32-16.25-generic-pae
Regression: No
RelatedPackageVersions: linux-firmware 1.32
Reproducible: Yes
SourcePackage: linux
TestedUpstream: Yes
Uname: Linux 2.6.32-16-generic-pae i686
dmi.bios.date: 05/11/2009
dmi.bios.vendor: LENOVO
dmi.bios.version: 7LETC6WW (2.26 )
dmi.board.name: 6459CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7LETC6WW(2.26):bd05/11/2009:svnLENOVO:pn6459CTO:pvrThinkPadT61p:rvnLENOVO:rn6459CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 6459CTO
dmi.product.version: ThinkPad T61p
dmi.sys.vendor: LENOVO

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 lucid

-- 
scaling_max_freq is cut upon system load
https://bugs.launchpad.net/bugs/536435
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