[Bug 632616] [NEW] Scheduler does not max all cores after suspend/resume

[Brian]

Public bug reported:

On my 4-core Dell laptop (E6410 with i7-620M), I can max all 4 cores
with a simple shell script. However, following a suspend/resume, the
same script will not max the cores. I noticed this problem when trying
to run R across all 4 cores.

I am using Ubuntu 10.04.1 LTS with kernel version 2.6.32-24.38.

Could someone else see if they can replicate this? Here's what should
work:

Cold boot.
Open System Monitor and look at 'Resources' tab, or run 'top'
Open multiple terminal windows (2/4/8 depending on your CPU)
In each terminal window run:

while true
do
find . -name "igdsh" -exec ll -d {} \;
find . -name "ngesaoiueah" -exec ll -d {} \;
find . -name "soihgwa" -exec ll -d {} \;
done

You should see CPU load max on all cores. Press Ctrl-C in each terminal window to stop the loops.
Now, suspend/resume and repeat. I saw max on one core only after suspend/resume. I have also seen max on 2 or 3 cores out of 4 when running R multicore. If I do a reboot, I can again max all cores.

Please move this if 'linux' is the wrong package--and let us know if you
have a multicore processor that doesn't behave like this.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: linux-image-2.6.32-24-generic 2.6.32-24.38 [modified: lib/modules/2.6.32-24-generic/kernel/drivers/usb/serial/option.ko lib/modules/2.6.32-24-generic/kernel/drivers/usb/serial/usb_wwan.ko lib/modules/2.6.32-24-generic/kernel/drivers/usb/serial/qcserial.ko]
Regression: No
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.32-24.38-generic 2.6.32.15+drm33.5
Uname: Linux 2.6.32-24-generic x86_64
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: STAC92xx Analog [STAC92xx Analog]
   Subdevices: 0/1
   Subdevice #0: subdevice #0
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: STAC92xx Analog [STAC92xx Analog]
   Subdevices: 2/2
   Subdevice #0: subdevice #0
   Subdevice #1: subdevice #1
AudioDevicesInUse:
 USER        PID ACCESS COMMAND
 /dev/snd/controlC0:  peyserb    1884 F.... pulseaudio
 /dev/snd/pcmC0D0p:   peyserb    1884 F...m pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xe9660000 irq 22'
   Mixer name	: 'IDT 92HD81B1C5'
   Components	: 'HDA:111d76d5,1028040a,00100104'
   Controls      : 18
   Simple ctrls  : 12
Card1.Amixer.info:
 Card hw:1 'NVidia'/'HDA NVidia at 0xe3080000 irq 16'
   Mixer name	: 'Nvidia ID b'
   Components	: 'HDA:10de000b,10de0101,00100100'
   Controls      : 0
   Simple ctrls  : 0
Card1.Amixer.values:
 
Date: Tue Sep  7 14:36:35 2010
HibernationDevice: RESUME=UUID=d22d6505-a1b5-4179-be5f-42fa73513992
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
MachineType: Dell Inc. Latitude E6410
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-24-generic root=UUID=b5182fc4-98ba-4e90-b1d4-d08a5f0c7aa1 ro quiet splash
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=en_US.utf8
RelatedPackageVersions: linux-firmware 1.34.1
SourcePackage: linux
dmi.bios.date: 03/05/2010
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A01
dmi.board.name: 0K42JR
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA01:bd03/05/2010:svnDellInc.:pnLatitudeE6410:pvr0001:rvnDellInc.:rn0K42JR:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6410
dmi.product.version: 0001
dmi.sys.vendor: Dell Inc.

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


** Tags: amd64 apport-bug lucid needs-upstream-testing resume suspend

-- 
Scheduler does not max all cores after suspend/resume
https://bugs.launchpad.net/bugs/632616
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