virtualbox.org

I have a VM I setup on a 2010 iMac (Core 2 Duo). It runs great. Windows 2000 Server guest OS.

Now I have been tasked with moving this VM to a Mac Pro host (OS X 10.7.5). It is a first generation Mac Pro. The VM boots fine on the Mac Pro, however, any network operations are several orders of magnitude slower than what I was getting when running it on the iMac. I'm using virtio-net for the network setup as well as bridged adapter. I've also tried using the Intel Pro/1000 MT Desktop for the adapter type and it doesn't seem to make a difference.

I was able to speed things up quite a bit on the Mac Pro by turning off the Hardware Virtualization under the Acceleration tab in the Machine Settings window. However, anything I do in the Windows guest that accesses the network causes 100% CPU usage and the performance is very slow. The networking on the OS X host is fine (file copies finish with performance expected of gigabit ethernet). Copies between the host and guest using shared folders in VirtualBox seems OK. I've also tried running OS X 10.6.x on the host to rule out any issues with 10.7.x and it didn't seem to make a difference.

Any ideas why I'm seeing such slow performance on a Mac Pro system? Also, I can't believe the disparity between this Mac Pro and an iMac that is only three years newer. Does that seem right?

-Matt

Did you check the task list to see what was eating CPU or I/O bandwidth?

I would doubt that turning off VT-x improves things. My own guess is that the Windows guest is upset by finding the network has changed, especially if you already had shared folders etc set up. No doubt it will take a while to adapt, so simply giving it time would be the most effective solution.

If you have several CPU configured for the VM, try with only one.

Waiting for the networking to "settle down" doesn't do anything. After booting, the Windows guest idles nicely until I do any network operations (such as a file copy). Once I do that, the CPU meter in Windows ramps up and stays peaked until the copy is finished. I installed a process monitor and it shows a high percentage of DPC in Windows, which would seem to indicate a driver issue. Since the problem only shows up during network operations, I'm inclined to think it is a network driver issue.

I've tried both the virtio drivers for networking as well as the Intel Pro, configuring VirtualBox accordingly for each one. I get the same result from either. I've nuked all of the drivers from Windows and reinstalled as needed when enabling/switching NICs in VirtualBox but it didn't seem to make a difference. I've even traded network cables and made sure the switch is performing correctly. Nothing seems to help.

It seems there is a lack of process trace tools for Windows 2000 to really see what is causing all of the DPC activity.

Again, this is using the *same* VirtualBox setup/image from a 2010 iMac. It performs wonderfully on that machine but exhibits the issues I've mentioned on a first gen. Mac Pro. The Mac seems fine otherwise, as I'm able to transfer files over the network without any difficulty when running OS X natively. So I don't think there is anything wrong with the machine or the host OS. The only thing I can figure is that it is something in the Mac Pro configuration that VirtualBox or the Windows guest doesn't like.

My next step is to try to install Ubuntu Server on the box as an alternative host OS and see if I can get my VirtualBox setup going under that. Maybe it will perform better than using OS X as the host OS (although I don't know why that would be - they should run the guest OS pretty much the same, theoretically).

Any other ideas?

-Matt

noteirak wrote:If you have several CPU configured for the VM, try with only one.

I only have one CPU allocated to the Windows guest in my VirtualBox configuration, so no worries there.