High host CPU load by Windows 2016 guest

Discussions about using Windows guests in VirtualBox.
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Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

High host CPU load by Windows 2016 guest

Post by Selin »

Hi.
Just want to share some experience I'd got yesterday.

Host:
- OS: FreeBSD 11.1 Release p6
- VirtualBox: 5.2.8 OSE
- CPU: Intel Xeon E5-2687W v4 (all virtualization BIOS settings are enabled)
Guest:
- OS: Windows Server 2016
- CPU: 12
- Chipset: ICH9 (I know it is still experimental, but I've used it for testing purpose. Moreover - another guest works perfect with the same config, but with only 2 CPU assigned)

Issue:
- host CPU is loaded by VBox service up to 50+% even when guest is in idle.
- guest works very slow, up to the DPC WATCHDOG VIOLATION BSOD

Solution:
- reduce number of CPU down to 2 or 1
OR
- change chipset to PIIX3

Also tried, but without success:
- disable hyperthreading
- reduce CPU assigned to guest down to 4
- install/uninstall VirtualBox Guest Addition

Unfortunately, I cannot guaranty this solution works for 100%, but in my case it is reproduced stable:
- switch to ICH9 - high load on host while guest is in idle
- switch to PIIX3 - host load is relevant to guest load
Martin
Volunteer
Posts: 2560
Joined: 30. May 2007, 18:05
Primary OS: Fedora other
VBox Version: PUEL
Guest OSses: XP, Win7, Win10, Linux, OS/2

Re: High host CPU load by Windows 2016 guest

Post by Martin »

Your CPU has only 8 physical cores, so a VM with 12 CPU is way too big.
You shold try to always keep a physical core "free" for the host to manage the running VMs.
How is the load when you keep your guest VM to max 6 virtual CPUs?
Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

Re: High host CPU load by Windows 2016 guest

Post by Selin »

Martin wrote:Your CPU has only 8 physical cores, so a VM with 12 CPU is way too big.
Nope.
https://ark.intel.com/products/91750/In ... e-3_00-GHz
# of Cores 12
# of Threads 24
Martin wrote:You shold try to always keep a physical core "free" for the host to manage the running VMs.
How is the load when you keep your guest VM to max 6 virtual CPUs?
On the one hand I have another server with 6 cores (12 threads) and it hosts guest with 6 CPUs assigned. And whole system is running good even under heavy load.

On the other hand I got freezes with 12 cores assigned to current guest. With heavy network load it becomes frozen in a few minutes.
Testing now with 10 cores (i.e. CPUs) assigned to guest...
Martin
Volunteer
Posts: 2560
Joined: 30. May 2007, 18:05
Primary OS: Fedora other
VBox Version: PUEL
Guest OSses: XP, Win7, Win10, Linux, OS/2

Re: High host CPU load by Windows 2016 guest

Post by Martin »

Selin wrote:
Martin wrote:Your CPU has only 8 physical cores, so a VM with 12 CPU is way too big.
Nope.
ok, missed the "v4" in the search engine results. ;)
Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

Re: High host CPU load by Windows 2016 guest

Post by Selin »

Confirm.
With 12 CPU (i.e. all cores) assigned guest freezes in a few minutes of network load. CPU/Disk load has no such influence.
With 10 CPU system has running for one hour so far without freezes.
socratis
Site Moderator
Posts: 27330
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: High host CPU load by Windows 2016 guest

Post by socratis »

So, let me see if I got this correctly...
  • You are using a feature X that's labeled as "DO NOT USE".
  • You find a problem with the setup.
  • You switch that feature X off.
  • Problem goes away.
Did I get this right? Is this what this post is all about?
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

Re: High host CPU load by Windows 2016 guest

Post by Selin »

Unfortunately, no.
With all default settings system anyway freezes time-to-time... It is only the question of time - some minutes or some hours :(

Found another one possible solution - disable AIO (async I/O).
https://bugs.freebsd.org/bugzilla/show_ ... ?id=168298
(FreeBSD 11.x has duilt-in AIO support, so either will try to turn it off by sysctl or move to 10.x where AIO was optional)

At least I see the following in the guest log on a new server (FreeBSD 11.1):

Code: Select all

AIOMgr: Default manager type is 'Async'
AIOMgr: Default file backend is 'NonBuffered'
while on old stable server (FreeBSD 10.3) I see:

Code: Select all

AIO: Async I/O manager not supported (rc=VERR_NOT_SUPPORTED). Falling back to simple manager
Maybe there is some option to disable async I/O for guests?
socratis
Site Moderator
Posts: 27330
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: High host CPU load by Windows 2016 guest

Post by socratis »

I just noticed (sorry about that), that you're using the FreeBSD port of VirtualBox. You need to talk to them I'm afraid, they're the ones maintaining it...
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

Re: High host CPU load by Windows 2016 guest

Post by Selin »

So there is no way to disable using AIO for guests from VirtualBox side, correct?
Martin
Volunteer
Posts: 2560
Joined: 30. May 2007, 18:05
Primary OS: Fedora other
VBox Version: PUEL
Guest OSses: XP, Win7, Win10, Linux, OS/2

Re: High host CPU load by Windows 2016 guest

Post by Martin »

We don't have the insight here about the VirtualBox built by/for FreeBSD.
Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

Re: High host CPU load by Windows 2016 guest

Post by Selin »

And yes - probably it is reasonable to move this topic to appropriate board... As this is looks like not Windows guest problem (Win 2008 R2 and 2016 - no difference), but FreeBSD host :(
Selin
Posts: 60
Joined: 7. Sep 2016, 17:00

Re: High host CPU load by Windows 2016 guest

Post by Selin »

Martin wrote:We don't have the insight here about the VirtualBox built by/for FreeBSD.
I'm asking here not about FreeBSD, but about VirtualBox option to disable using AIO for guests.
socratis
Site Moderator
Posts: 27330
Joined: 22. Oct 2010, 11:03
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Win(*>98), Linux*, OSX>10.5
Location: Greece

Re: High host CPU load by Windows 2016 guest

Post by socratis »

You are asking about a VirtualBox fork that is being maintained by the FreeBSD people. Therefore, you have to ask in the FreeBSD forum. For any feature or problem involving the FreeBSD port of VirtualBox.

The AIO module that's causing the problems is a FreeBSD feature. I would continue the discussion in the FreeBSD ticket that you already linked to...
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
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