High VMM Load on Intel CPUs introduced in 6.1.20

[lbgaus]

Beginning in version 6.1.20, and also happening in .22, and .24, there is a significant increased VMM Load reported in the Session Information dialog with hosts running Intel processors when using 2 or more vCPUs, getting progressively worse as the vCPU count is increased up to the recommended threshold shown in the VM Settings dialog.

I reverted to 6.1.18 and confirmed the issue is not present in this version, with low to minimal VMM Load.

I tested and am not seeing the issue on a Ryzen 5 3400G host at this time. I have performed the same test with multiple vCPUs with 6.1.20, and 6.1.24 and the VMM Load is low in all these cases on a Ryzen host.

All hosts tested are running Windows 10 x64. Tested and confirmed issue with Windows 10 x64 and Debian x86-64 guests on Intel 3rd gen Core i5, Core i7 5820K, Xeon E5-1620 v2, and Xeon E5-2620 v4 CPUs.

[ebk]

Have the same problem,now my ticket is duplicated. https://www.virtualbox.org/ticket/20526

[lbgaus]

Can someone please take a look at this? The release is already up to 6.1.30 and the problem has not been addressed yet and nobody has offered any thoughts. I am seeing very high VMM load on Intel Xeon CPUs on several systems I am testing when the number of vCPUs is 2 or above.

The changelog for 6.1.20 says the following...

VMM: Fixed extremely poor VM performance depending on the timing of various
actions (regression in 6.1.0)

Can someone elaborate on what was changed, why, etc... is there a way to switch back to the previous mode?

[ebk]

Replying to lbgaus:

Can someone please take a look at this? The release is already up to 6.1.30 and the problem has not been addressed yet and nobody has offered any thoughts. I am seeing very high VMM load on Intel Xeon CPUs on several systems I am testing when the number of vCPUs is 2 or above.

The changelog for 6.1.20 says the following...

VMM: Fixed extremely poor VM performance depending on the timing of various
actions (regression in 6.1.0)

Can someone elaborate on what was changed, why, etc... is there a way to switch back to the previous mode?

There's already a forum thread for this. It seems like a false positive. There's no big performance difference when tested on Hyper-V and virtualbox.

[Chester Banach]

I too, have the same issue and an waiting to upgrade from version 6.1.18 when this bug has been addressed. I don't want support to think that there are only 2 people out there with this issue. If there are others that have experienced this issue, post your concerns as well. Maybe if there are more of us it will be addressed.