Bug 15896 - Powernow-k8 detects wrong p-states for AMD Thuban 6-core processor (1090T)
Summary: Powernow-k8 detects wrong p-states for AMD Thuban 6-core processor (1090T)
Status: CLOSED CODE_FIX
Alias: None
Product: Power Management
Classification: Unclassified
Component: cpufreq (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: cpufreq
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-05-02 17:38 UTC by Larkin Lowrey
Modified: 2011-07-30 06:28 UTC (History)
1 user (show)

See Also:
Kernel Version: 2.6.33.3
Subsystem:
Regression: No
Bisected commit-id:


Attachments

Description Larkin Lowrey 2010-05-02 17:38:32 UTC
Output during boot:

powernow-k8: Found 1 AMD Phenom(tm) II X6 1090T Processor processors (6 cpu cores) (version 2.20.00)
powernow-k8:    0 : pstate 0 (3600 MHz)
powernow-k8:    1 : pstate 1 (3200 MHz)
powernow-k8:    2 : pstate 2 (2400 MHz)
powernow-k8:    3 : pstate 3 (1600 MHz)

My understanding of AMD's Turbo Core is that the 3.6GHz p-state 0 is supposed to be a hidden hardware p-state and that the OS kernel should see hw p-state 1 (3.2GHz) as it's p-state 0.

My expectation is to see:
p-state 0: 3200 MHz
p-state 1: 2400 MHz
p-state 2: 1600 MHz
p-state 3:  800 MHz

Note: the lowest clock 800MHz is missing from the list output by powernow-k8. 

I am running this on a Gigabyte GA-890GPA-UD3H v1 board with the latest non-beta bios F6. The bios does support, and recognize, the 1090T processor. I do have the Turbo Core option enabled in the bios.

While cpufreq does identify the hw p-state 3600MHz, it does not use it. I have run mprime with 1 thread and with 6 and there is never any time recorded for 3600MHz. When under full load, cores run at 3200MHz, which is expected.
Comment 1 Larkin Lowrey 2010-05-13 17:59:09 UTC
Resolved in 2.6.33.4

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