Bug 474132 - ondemand on scaling erratic and inconsistent on T8100
Summary: ondemand on scaling erratic and inconsistent on T8100
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 10
Hardware: All
OS: Linux
low
high
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2008-12-02 11:53 UTC by James
Modified: 2009-06-30 19:26 UTC (History)
2 users (show)

Fixed In Version: kernel-2.6.29.5 + ignore_tpc patch
Clone Of:
Environment:
Last Closed: 2009-06-30 19:26:11 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Linux Kernel 12388 0 None None None Never

Description James 2008-12-02 11:53:53 UTC
Description of problem:
On my T8100 notebook, the ondemand governor will only take the processor to full-speed (2.1 GHz) if a demanding job is running on Core 1. If the job is on Core 0, it'll only go up to 1.2 GHz. scaling_max_freq is correct at 2101000 in sysfs for both CPUs.

Version-Release number of selected component (if applicable):
kernel-2.6.27.7-132.fc10.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. Get a job running on Core 0.
  
Actual results:
CPU only goes up to 1.2 GHz.

Expected results:
CPU goes up to maximum speed (2.1 GHz).

Additional info:
For ACPI dump see bug 448150.

Comment 1 James 2008-12-03 11:13:36 UTC
I've just checked and this bug does not appear to manifest in kernel-2.6.27.7-53.fc9.x86_64.

Comment 2 James 2008-12-09 19:33:39 UTC
Still present in kernel-2.6.27.8-144.fc10.x86_64. It now caps on 1.6 GHz or sometimes 2.100 GHz (maximum is actually 2.101 GHz). Either way, load metering differs between Core 0 and Core 1.

Comment 3 James 2008-12-15 15:45:01 UTC
kernel-2.6.27.9-155.fc10.x86_64 is as comment #2.

Comment 4 James 2008-12-16 10:12:14 UTC
I've furthermore observed that, when *first booted on battery power*, the CPU will [eventually] scale up to 2.1 GHz. Normally on battery power, it should only go to 1.2 GHz. If I press the "low power" button, it *does* start to limit itself to 1.2 GHz as it should, and also thereafter when on battery power; on mains, all speeds are available (provided the governor selects them).

Comment 5 James 2009-02-12 14:05:29 UTC
ondemand scaling seems much improved in kernel-2.6.29-0.20.rc3.git12.fc10.x86_64, now supporting independent core frequencies and correct metering. Closing in deference to upstream.

Comment 6 James 2009-03-13 01:21:05 UTC
Re-opening, it's not fixed. Core 0 actually appears to operate slower than reported in sysfs.


Note You need to log in before you can comment on or make changes to this bug.