2008 R2 Cool n' Quiet

cortexodus

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I've installed Server 2008 R2 Sp1 on a Gigabyte 990FXA-UD3 with an FX-8120 and the CPU sits at 98% maximum frequency 100% of the time instead of downclocking as expected (and observed) as it does Win7 Pro. If I manually set the "maximum processor state" in power options to something lower like 50%, the CPU will clock down to that defined maximum and sit there.

Has anyone experienced this type of thing before? Any ideas how to get the system to downclock when there is no load?

As an aside, I did install the scheduler patches for Bulldozer before I noticed this issue. Not sure if it's related at all, though.

*I think this may have something to do with the Hyper-V role. However, my other Hyper-V box is on a Phenom II X6 1045T and power management seems to functioning without issue. The host's CPU frequency is dropping all the way to 28% when load is very low.
 
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Crystal Gaol

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What was the power management profile set to before you started changing things?

If you set the power management setting to Balanced or Power Saver. this will enforce throttling for you.
 

cortexodus

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It was set to Balanced. Unfortunately, it just sits at 98% of processor frequency. If I set to high performance it jumps to 102-104%. Setting to OOB power saving drops it to 75%. The lowest it will go if I manually set the maximum frequency is 44% (~1.4Ghz).
 

Crystal Gaol

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You installed both updates mentioned in that anandtech article then?

If so, did you read KB2646060 notes, it mentions the following two important points:

1) When this update is installed, Bulldozer modules will be less likely to achieve the C6 power state. This potentially results in increased power consumption in more lightly-threaded environments.

2) If you apply this update, you cannot revert the settings by uninstalling this update.

Edit - Anandtech had the KB patch order reversed. KB2645594 is first, then KB2646060, based on Microsoft's recommendation on KB2646060.
 

cortexodus

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You installed both updates mentioned in that anandtech article then?

If so, did you read KB2646060 notes, it mentions the following two important points:

1) When this update is installed, Bulldozer modules will be less likely to achieve the C6 power state. This potentially results in increased power consumption in more lightly-threaded environments.

2) If you apply this update, you cannot revert the settings by uninstalling this update.

Edit - Anandtech had the KB patch order reversed. KB2645594 is first, then KB2646060, based on Microsoft's recommendation on KB2646060.

I missed the first point you mention, but I was aware of the correct order of installation. I think I will just ditch the installation and redo it, then see at what point the performance issue occurs.
 

cortexodus

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Have you made any changes in the BIOS like disable power saving states?

BIOS is updated to F9. Power saving features are all enabled, core boost is disabled. I've discovered that (at least on the machine I'm working with) installation of the Hyper-V role induces the processor to remain at maximum clock. Subsequent removal of the role returns the CPU to normal clocking behavior. This is with an OOB installation of Server 2008 R2 w/ SP1 without the scheduler patches for Bulldozer.

I'm at a loss at this point...
 

Crystal Gaol

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What patches are you considering using?

While I personally have shuned AMD CPU servers for years, I have googled and found no less than three updates that may apply to your situation:

1) KB2568088 - This enables Windows to utilize AVX with Hyper-V on the Bulldozer platform. From what the KB article mentions, this is only necessary IF you are unable to launch guests. There is also a workaround that does not involve this patch, which I assume can be used to confirm whether or not this hotfix is appropriate. Also, this update may have been rolled into another, after the fact. Didn't look into that.

2) KB2645594 - Affects CPU scheduling for the Bulldozer platform. The notes indicate that you may still have poor performance due to incorrect power management. Also, note one of the files that gets patched, Powrprof.dll, Power Profile Helper DLL.

3) KB2646060 - Makes it really hard to park Bulldozer cores after installing 2645594. Also, not removable.

Since power management returns to normal after uninstalling the Hyper-V role then I suspect that there is some code in the Hyper-V role which affects the Bulldozer processor. We know that it only picks on this processor because your other platform doesn't experience this and a google search doesn't quickly indicate any other cases of this.

I would probably recommend visiting the Microsoft forums and post there your findings and hope for a response from MS. I've googled them pretty hard and found nothing conclusive. If you're a MS Partner your will get a response from Microsoft.

If you don't get a satisfactory response from Microsoft or elsewhere, you're going to have to make decision: To keep the current CPU platform and live without power management or replace the CPU platform with one that does. Perhaps another hypervisor would be in order?
 
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cortexodus

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What patches are you considering using?

While I personally have shuned AMD CPU servers for years, I have googled and found no less than three updates that may apply to your situation:

1) KB2568088 - This enables Windows to utilize AVX with Hyper-V on the Bulldozer platform. From what the KB article mentions, this is only necessary IF you are unable to launch guests. There is also a workaround that does not involve this patch, which I assume can be used to confirm whether or not this hotfix is appropriate. Also, this update may have been rolled into another, after the fact. Didn't look into that.

2) KB2645594 - Affects CPU scheduling for the Bulldozer platform. The notes indicate that you may still have poor performance due to incorrect power management. Also, note one of the files that gets patched, Powrprof.dll, Power Profile Helper DLL.

3) KB2646060 - Makes it really hard to park Bulldozer cores after installing 2645594. Also, not removable.

Since power management returns to normal after uninstalling the Hyper-V role then I suspect that there is some code in the Hyper-V role which affects the Bulldozer processor. We know that it only picks on this processor because your other platform doesn't experience this and a google search doesn't quickly indicate any other cases of this.

I would probably recommend visiting the Microsoft forums and post there your findings and hope for a response from MS. I've googled them pretty hard and found nothing conclusive. If you're a MS Partner your will get a response from Microsoft.

If you don't get a satisfactory response from Microsoft or elsewhere, you're going to have to make decision: To keep the current CPU platform and live without power management or replace the CPU platform with one that does. Perhaps another hypervisor would be in order?

At the moment I have no planned patches of any kind. When I ran Win 7 Pro on this box (it used to be my main), I would install the scheduler patches that you referenced without any issues. Whether they helped performance or not is up in the air since I never really tested it but I know the power management stuff worked ok.

I've googled up and down for anything regarding Bulldozer being forced to max CPU freq. by the Hyper-V role to no avail. Posting in MS forums is something I just hadn't got to yet. I'm no MS partner or anything, I'm just tinkering with stuff since my job affords me an MSDN subscription that grants me access to everything under the sun for development. This is far from any kind of production level setup and just amounts to me being curious/bored.

It's not really a big deal if the power management features don't work "as normal" since this box was never going to be anything but a learning tool anyway, but I was sorta thinking about acquiring another Phenom II X6 cpu just to see if the motherboard or the 8120 itself is the issue. It had occurred to me to give something like ESXi a shot since I've never tried it out.

Thanks for looking into it :)
 

Crystal Gaol

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Just did some research, by being a MSDN subscriber you get priority support on at both the MSDN and TechNet forums. There are only select forums that Microsoft supports and they are listed here

MSDN Priority Forum Support: http://msdn.microsoft.com/subscriptions/aa974230.aspx
TechNet Priority Forum Support: http://technet.microsoft.com/subscriptions/ms788697.aspx

You would probably pick http://social.technet.microsoft.com/Forums/en-US/winserverhyperv/threads as your forum. Make sure you're signed in with your MSDN-activated Live account before posting.

If the community doesn't answer your question within two days, then Microsoft will.
 

cortexodus

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1) KB2568088 - This enables Windows to utilize AVX with Hyper-V on the Bulldozer platform. From what the KB article mentions, this is only necessary IF you are unable to launch guests. There is also a workaround that does not involve this patch, which I assume can be used to confirm whether or not this hotfix is appropriate. Also, this update may have been rolled into another, after the fact. Didn't look into that.

Thought I would let you know that installation of this patch actually solved the CPU maximum frequency issue. I decided to actually setup a VM and discovered I could not get it to fire up, then remembered your mention of this. Following its installation, Hyper-V is working as expected and the CPU is scaling appropriately. Thanks again for your thoughts on this! :D
 
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