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bungee91

Does UnRAID Have Hugepages Support, IOMMU super pages?

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A little new to this topic, but basically from what I've read if the processor supports it, it is a good idea to enable it.

From what I can tell this needs to be added to the XML in the

<memoryBacking> as such

<memoryBacking>
<hugepages/>
</memoryBacking>

 

I looked at my XML created by the VM manager and it is not there by default (nor selectable at VM creation).

I understand I can add it manually and test, etc... however there seems to (possibly) be more to it.

 

The support for this also looks to be needed in other files such as /etc/sysctl.conf (not sure if this is the same in UnRAID implementation).

 

I know my processor supports it, so I'd like to enable it. I started reading about it at the bottom here http://vfio.blogspot.com/2015_10_01_archive.html

"A more subtle feature also found in these E series processors is support for IOMMU super pages.  The datasheets for the E5 Xeons and these High End Desktop Processors indicate support for 2MB and 1GB IOMMU pages while the standard Core i5 and i7 only support 4KB pages"

 

And found some instructions for KVM here https://help.ubuntu.com/community/KVM%20-%20Using%20Hugepages

 

 

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UnRAID leverages transparent huge pages.

 

Do I need to add anything to the XML for this to be applied to the VM, or by leveraged you mean it's global and nothing needs to be done individually?

Thanks.

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UnRAID leverages transparent huge pages.

 

Do I need to add anything to the XML for this to be applied to the VM, or by leveraged you mean it's global and nothing needs to be done individually?

Thanks.

It's automatic. Nothing you need to do.

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UnRAID leverages transparent huge pages.

 

Do I need to add anything to the XML for this to be applied to the VM, or by leveraged you mean it's global and nothing needs to be done individually?

Thanks.

It's automatic. Nothing you need to do.

Sweet, thanks again!

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Any chance to have "huge pages" as an option for the few of us with 384GB RAM? Or any guides to manually enables this? Seems that system with a lot of RAM can benefit from this according to this video:

https://youtu.be/1yFQd4MaKK0?t=654

from 09:36 Linus explains the issue.

 

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Posted (edited)

Hi M0ngr31,

 

I think I may have stumbled upon the root cause, after watching an episode of linus' tech tips. He had some problems with his VM and it turned out to cause by a great amount of RAM. I have 384GB (funny enough the same amount Linus had in his machine) How much do you have in yours?

I have made a thread which describing my scenario, maybe you can confirm?

https://forums.unraid.net/topic/82427-spontaneous-reboots/?tab=comments#comment-764418

 

/Alphahelix

Edited by Alphahelix

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I only have 80GB in my box, so I don't have the same issues. I was more curious about the changes they made for Linus after I saw the video. And maybe if it'd speed anything up on mine.

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