Unusable Slowness In 2.6.38-8
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Linux |
Invalid
|
High
|
|||
linux (Ubuntu) |
Invalid
|
Medium
|
Unassigned |
Bug Description
After upgrading from 10.10 to 11.04, I found that my system ran several orders of magnitude more slowly. For example, as part of my debugging process I removed and reinstalled the proprietary nVidia drivers. Running `sudo aptitude remove nvidia-current` in a gnome-terminal required 15 minutes of wall-clock time. During this, I had a second terminal open with `top` running, and it showed that throughout this 15 minute ordeal aptitude or one of its subprocesses (dkpg, man-db, etc) was pegging the CPU to 90% or greater utilization. Starting a web browser to file this report took about 10 minutes, then another 2-3 just to render the simple page. Characters appear in this box multiple seconds after I type them. Etc.
This is the case with the Unity shell and with Ubuntu Classic without visual effects (or whatever it is called). It happens with nvidia, nv, and nouveau. However, if I boot into my old kernel (2.6.35-28), then I get the same responsive system that I had been used to.
I was able to find very few similar sounding reports on the web, and all of them are from people using the same family of hardware: the N51 line of laptops by ASUS. See, for example, http://
I imagine it will be rather difficult to debug a hardware-specific problem without having access to that hardware, and I can get by using the old kernel, but I will be happy to perform any tests or provide any further information that might be deemed useful.
ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: linux-image (not installed)
ProcVersionSign
Uname: Linux 2.6.38-8-generic x86_64
NonfreeKernelMo
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: amd64
ArecordDevices:
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
Card hw:0 'Intel'/'HDA Intel at 0xfbff8000 irq 50'
Mixer name : 'Realtek ALC269'
Components : 'HDA:10ec0269,
Controls : 13
Simple ctrls : 8
Card1.Amixer.info:
Card hw:1 'NVidia'/'HDA NVidia at 0xfde7c000 irq 16'
Mixer name : 'Nvidia GPU 0a HDMI/DP'
Components : 'HDA:10de000a,
Controls : 16
Simple ctrls : 4
Date: Mon Jun 6 05:30:36 2011
HibernationDevice: RESUME=
MachineType: ASUSTeK Computer Inc. N51Vn
ProcEnviron:
LANGUAGE=en_US:en
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: root=UUID=
RelatedPackageV
linux-
linux-
linux-firmware 1.52
SourcePackage: linux
UpgradeStatus: Upgraded to natty on 2011-06-05 (0 days ago)
WpaSupplicantLog:
dmi.bios.date: 06/12/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 211
dmi.board.
dmi.board.name: N51Vn
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.chassis.
dmi.modalias: dmi:bvnAmerican
dmi.product.name: N51Vn
dmi.product.
dmi.sys.vendor: ASUSTeK Computer Inc.
Changed in linux (Ubuntu): | |
status: | New → Confirmed |
Changed in linux: | |
importance: | Unknown → High |
status: | Unknown → Incomplete |
tags: | added: needs-upstream-testing |
tags: | added: regression-release |
tags: |
added: kernel-bug-exists-upstream-3.7.0-030700rc1 removed: needs-upstream-testing |
tags: |
added: needs-upstream-testing removed: kernel-bug-exists-upstream-3.7.0-030700rc1 |
Changed in linux: | |
status: | Incomplete → Invalid |
I ran a test of my own devising, in which I wrote a trivial C program that calculates the square of a number using a quadratic algorithm, built it, and ran it under both the old and new kernels. Here are the results:
[2.6.35-28 kernel] asus:~/ temp/testing$ time ./a.out 20000
chad@siga-
The square of 20000, calculated very slowly, is 400000000
real 0m1.045s
user 0m1.040s
sys 0m0.000s
[2.6.38-8 kernel] asus:~/ temp/testing$ time ./a.out 20000
chad@siga-
The square of 20000, calculated very slowly, is 400000000
real 0m53.264s
user 0m49.130s
sys 0m3.100s
Since the "real" time is roughly the sum of "user" and "sys", this seems to be a confirmation that the CPU is the problem, rather than memory or I/O transfers. More interestingly, the "user" time dominating the "sys" time, which seems to indicate that it is not just system calls that are running at a glacial pace.