Slow client, possibly related to hardware(?)

[John D. West]

Hardware: Dell Precision WorkStation T5400, dual Xeon E5405 @ 2.0GHz Host: Ubuntu 10.04 64-bit or Red Hat Enterprise Linux Client release 5.3 Client: Ubuntu 10.04 64-bit

I have a web/database app on a Ubuntu 10.04 client in VirtualBox 3.2.8. When installed on either of two i7 processor boxes (one Ubuntu 10.04, one Windows 7) a given page (large) loads in 26-34 seconds. This is acceptable to my users.

When the same client is installed on the above Dell Workstation, the same page loads very slowly, 8-11 minutes. All processors are pegged during that time. I initially had the issue with RHEL (kernel 2.6.18-128.el5) on the host, then wiped the host and installed Ubuntu 10.04 (kernel 2.6.32-24-generic). No noticeable difference.

Reducing the client to only 1 processor speeded things up slightly, the page load then dropped to 3.5 minutes. Still unacceptable to my users, but better.

I installed VMware Workstation, and copied the client files into VMware. When I started the machine, I was presented with a message warning me that kernel.sched_compat_yield was turned off, and this would adversely affect performance. I turned it on, and the VMware client loads the page in 28 seconds. I left kernel.sched_compat_yield on and tried the VirtualBox client again, and it still takes 8+ minutes to load the same page.

Tentative conclusion: there is something with this hardware that VMware handles OK and VirtualBox does not.