Poor mutex and semaphore performance
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Confirmed
|
Low
|
Unassigned |
Bug Description
I noticed the results of this blog post:
http://
and I was curious if the same sort of issue existed with the linux kernel and if it would shed any light on Bug #1058854
https:/
The results don't appear to be as bad as those seen on Mac OS X, but they definitely are a lot poorer than I expected/hoped they would be. The code that builds on Linux is now available on that blog port and I created a git repo with the history here:
https:/
Here are the results from running it on the the same HP Pavilion dm4 that as the results from Bug #1058854:
mutex
1 thread real 0m 0.514s user 0m 0.512s sys 0m 0.000s
2 threads real 0m 4.382s user 0m 5.176s sys 0m 3.544s
4 threads real 0m 9.953s user 0m 9.709s sys 0m22.417s
8 threads real 0m20.984s user 0m14.973s sys 1m 8.256s
16 threads real 0m38.725s user 0m28.426s sys 2m 5.484s
benaphore
1 thread real 0m 0.324s user 0m 0.312s sys 0m 0.008s
2 threads real 0m 6.372s user 0m 6.380s sys 0m 5.572s
4 threads real 0m17.820s user 0m12.273s sys 0m42.495s
8 threads real 0m40.266s user 0m25.626s sys 2m14.400s
16 threads real 1m40.090s user 0m52.939s sys 5m45.802s
mutex2
1 thread real 0m 0.325s user 0m 0.320s sys 0m 0.004s
2 threads real 0m 0.730s user 0m 0.816s sys 0m 0.384s
4 threads real 0m 2.328s user 0m 3.388s sys 0m 5.704s
8 threads real 0m 4.096s user 0m 5.328s sys 0m10.705s
16 threads real 0m 7.584s user 0m 9.609s sys 0m20.401s
---
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu13
Architecture: amd64
ArecordDevices:
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: STAC92xx Analog [STAC92xx Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
Card0.Amixer.info:
Card hw:0 'PCH'/'HDA Intel PCH at 0xc0800000 irq 50'
Mixer name : 'Intel CougarPoint HDMI'
Components : 'HDA:111d76e0,
Controls : 22
Simple ctrls : 10
DistroRelease: Ubuntu 12.04
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
MachineType: Hewlett-Packard HP Pavilion dm4 Notebook PC
Package: linux (not installed)
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=
ProcVersionSign
RelatedPackageV
linux-
linux-
linux-firmware 1.79.1
StagingDrivers: rts_pstor mei
Tags: precise running-unity staging
Uname: Linux 3.2.0-31-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 01/17/2012
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.08
dmi.board.
dmi.board.name: 1793
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 41.1C
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.
dmi.modalias: dmi:bvnHewlett-
dmi.product.name: HP Pavilion dm4 Notebook PC
dmi.product.
dmi.sys.vendor: Hewlett-Packard
Changed in linux (Ubuntu): | |
importance: | Medium → Low |
status: | Incomplete → Confirmed |
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1058864
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.