virtualbox.org

Hello!

I am doing some testing with VirtualBox. I would like to see how it works with Windows 8.1 Pro as a guest operating system. On my test machine (a Dell E6440 laptop - i7 processor, 8GB RAM, hybrid solid state drive), I have tried the following scenarios:

Ubuntu 14.04 Host with Windows 8.1 Guest
Windows 8.1 Host with Windows 8.1 Guest

In both cases, I experienced terrible performance in both the guest and host operating systems, ONLY when the guest was running. I do not see this issue when I work with an Ubuntu guest (so it's only Windows). I have tried several things in an attempt to pinpoint the cause of this performance loss across multiple host OSs, including disabling 3d acceleration and allotting more RAM/Processors/etc. In all cases, the same symptoms are present.

Has anyone experienced this? If so, are there any suggestions for improving this situation? Does VirtualBox not yet work well with Windows 8.1 as a guest?

Thanks for your help.

If you mean does Windows 8.1 run well as a guest in VirtualBox it runs just fine. Did you install the guest additions in the Windows guest?

Attach the vbox.log for your Windows guest.

You'll have to be a lot better at precisely characterizing the problem than just saying the performance is "terrible". Maybe that means something to you, but not anyone else.

Is the guest eating all the disk bandwidth by any chance? Windows is kind of good at that when installing updates and doing maintenance...

JeremyH wrote:I am doing some testing... I would like to see how it works... I experienced terrible performance in both the guest and host operating systems... I have tried several things... the same symptoms are present...

You don't describe your setup adequately, you don't describe your end goal, you don't describe which tests you run that measure the performance in numbers, you don't describe in detail what you tried. How can you expect a meaningful answer?

Seriously, if you want to have a meaningful discussion, we need more details. Way more... Including a guest's log file (zipped) like Louis asked and the detailed setup of guest and host. See: Minimum information needed for assistance.

Attached is my log. Thanks for your help.

Specifically what I am seeing is repeated ~30 second hangs on both host and guest. Happens maybe once every minutes to 3 minutes. Same exact behavior across Ubuntu and Windows hosts. Very strange! On my Windows host, I do see VERY high disk usage by VirtualBox. Total disk usage is at 100% on the host. This is probably the issue.

Forgot to mention that I did install the guest additions on this guest.

JeremyH wrote:Forgot to mention that I did install the guest additions on this guest.

The log you posted isn't complete. You have to shutdown the guest first then post the vbox.log (compressed). I don't see that the guest additions are installed nor is the extension pack.

Sorry about that. Attached is the log after shutting down the guest.

no problem. still no guest additions or extension pack installed.
dozens if not hundreds of this:

00:01:18.980090 AsyncCompletion: Task 0x0000001abc8b80 completed after 11 seconds
00:01:18.980829 AsyncCompletion: Task 0x0000001abc8b40 completed after 11 seconds
00:01:18.981071 AsyncCompletion: Task 0x0000001abc8b00 completed after 11 seconds
00:01:18.981159 AsyncCompletion: Task 0x0000001abc8ac0 completed after 11 seconds
00:01:18.981396 AsyncCompletion: Task 0x0000001abc8a80 completed after 11 seconds
00:01:18.981578 AsyncCompletion: Task 0x0000001abc8a40 completed after 11 seconds
00:01:18.981704 AsyncCompletion: Task 0x0000001abc8a00 completed after 11 seconds

not sure if that is because of no GAs or extension pack or something else.

"00:00:34.434533 AsyncCompletion: Task 0x0000001abeeb00 completed after 10 seconds"

Neither the GAs nor the extension pack should affect this. AFAIK "AsyncCompletion" refers to the task that does background writes to the host drive. If it is taking 10 seconds plus to write one packet then there is something odd about the drive. I have seen errors like this when there are errors on the host drive, and I've also seen it when the VDI host folder is on a network drive (and presumably a buggy network card driver?). You can bypass the problem by turning off "Use Host I/O Cache" for the virtual drive, but I think it's better to fix the real problem.

Another thing that jumps out at me is the folder name: "Windows 8.1 ********". The '*' symbol is typically used as a "match anything" wildcard. To use this in the VM name strikes me a extremely unwise, though I don't know if it actually causes a problem.

Finally, when you have a dual core host CPU it isn't IMHO a good idea to hand both cores to the VM. That leaves the host with 0 cores, which isn't a good idea if you want it to do any work (like background writes to disk). And to forestall the inevitable response: threads are not cores. If they were then you wouldn't need to pay a premium for cores.

Have a look at viewtopic.php?f=6&t=32134 and see if disabling the host I/O caching like mpack suggested has any effect. VM Settings, Storage, Controller, Use Host I/O Cache.

I thought I would mention "Use Host I/O Cache" is normally disabled by default for the SATA controller.

Thank you all for your suggestions. I tried disabling the Use Host I/O Cache and the performance is VASTLY improved. Disk usage on both guest and host was 100% before, now disk usage on both is normal (idling between 0 and 25%).

As for guest additions, I'm not sure why the logs would show that they are not installed as it looks as though they are to me. I ran through the install process and the little VBox icon is in the lower tray in the guest.

As for multiple cores, the Virtualbox management utility tells me I have four available so I assigned it two. Is this not a good idea?

Thanks again to all for the assistance.

If the log is correct you have an Intel i5-3570 with 4 cores and 4 threads (no hyper-threading) so assigning 2 should be fine.

Interesting, this is actually an i7-4600M with 2 cores (4 logical cores). So, VirtualBox must be looking at the logical cores. Is it a red flag that it sees the wrong information?