VMware Communities
Pickwick81
Contributor
Contributor

poor perfomance of virtualized Windows XP 32 Bit with ACPI kernel

Hello all,

I've recently bought Workstation 8 to virtualize a Windows XP 32 Bit with an installation of Borland Builder 5 to just compile a program of mine. The host is a Windows 7 64 Bit Ultimate with 4 GB RAM and a Core 2 Duo T7700 or something like that with 2,4 GHz. The virtual machine has 2 GB RAM assigned and I'm pretty sure that no swapping occurs.

The problem now is that compiling my application in the XP-guest is about 3 to 4 times slower than compiling it native. The XP-guest is doing nothing else, no running background services for virus scanning or stuf flike that. I tested with ACPI settings and found that whenever I use an ACPI enabled Kernel in the guest the perfomance is pretty poor. If I change the kernel to be a default, non ACPI-available kernel the perfomance is almost like compiling native. Of course I want ACPI in the guest because of the automatic shutdown and I hoped to give the guest both of my CPU cores. This does only work well if the guest uses an multicore, ACPI-aware kernel. But whenver ACPI is used in the guest, I'm stuck with poor performance.

I already searched the web and my problem is not a drifting clock, to fast or slow times or stuff like that, so setting the host cpu clock in VMWare didn't change anything. The host is configured to give maximum performance, too, within bios settings and Windows itself. What I recognized was, that if the XP-guest is ACPI-aware during compilation of my software the Windows kernel times in Task Manager fo guest and host are pretty high, while on native compilation and without ACPI in the guest the kernel times are pretty slow.

A collegue of mine did some testings with pretty much the same CPU on a Linux host using VMWare Server 2 and VirtualBox and had the same results. Wehenver ACPI is used in the guest the VM is much to slow. He also tested with ESXi 5 on another dedicated machine and the problem didn't occur there. With ACPI enabled in the guest and one or two virtual CPUs there was no poor perfomance.

Does anyone has an idea why this happens? I thought ACPI problems where solved during the years. Windows needs ACPI for more than one CPU, or the host will always have 100 CPU load, and I don't see why I should not be able to use automatic shutdown and stuf flike that.

Reply
0 Kudos
0 Replies