virtualbox.org

For quite a while now, I've been running Ubuntu VMs on my CentOS7.2 laptop. I believe there was a time that the performance on these VMs was reasonable. However, for quite a while now, I've found that the Ubuntu VM has been running very slowly, even painfully. I had only been using a 14.04 VM for quite a while, but I just created a 15.10 VM, and the behavior is just about the same.

The base laptop (HP Zbook) has 16g RAM, and apparently 8 cpus, and except for the VM performance, works pretty well.

I typically allocate 2 CPUs to each VM.

I noticed that when the VM is trying to do work, I can watch "top" on the base machine, and VirtualBox is the top process, usually using over 200% CPU. Even when the VM is basically idle, VirtualBox is still the top process, taking over 100% CPU.

What else can I look at to get more information?

Post the guests log file ( as an attachment ). Right click on the guest in the Main Manager then click show log. Save and post as an attachment. Compress if it is too large to post.

Actually, I think I found a resolution for this. My laptop has 8 cpus, the VM was set to use only 2. I changed it to use 4, and now its performance is much better. I'll note this information about obtaining that log file, but I think I'm fine for now.

Make sure that it is not 8 vCPUs if so you will have a different issue.
Only the log file will tell us.