Multicore CPU Freqiency scaling broken
Bug #462284 reported by
hal
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Expired
|
Undecided
|
Unassigned |
Bug Description
When I run 4 cpu intensive process on Quad Core on the 9.10-rc amd64 i found that the performance is decreased compared to 9.10 alpha3. After some investigation I found that the frequency scaling is not working correctly. Often for some cores low frequency is reported and "top" reports load of 0% for this core, and on one of the other cores 2 processes are run.
This is not ovserved on 9.10 aplha3
Changed in ubuntu: | |
status: | New → Confirmed |
To post a comment you must log in.
I am affected too.. after an upgrade from 9.04. Please see the attachment.
Have a look at the execution times of the same code (left terminal). It varies between 39, 45 and 57 seconds. The most often it is 57s. before the upgrade it was always 39. Please note the process distribution: CPU0 is almost not loaded. Also note the frequency on (bottom right) it is 2G not 2.66.
Something else: When I change the freq by hand to "2.66" or "Performance" or what ever it returns back to "Ondemand" within several seconds.
It is annoying... I do not know if it is the kernel or something else...