After over a week of bashing my head against a wall I think I've finally got VMware (Workstation 6.5) running solidly under 2.6.26.

The solution appears to simply be to lock it to a single core:

for proc in `pgrep vm`; do sudo taskset -p -c 1 $proc; done

In this example I'm using pgrep to find all vmware related processes, and taskset to lock them to CPU#1 (the second core on my laptop), as I run only single-core VM's I don't have any issues there.

I've no idea what changed in 2.6.26 to make this necessary, but this might help someone out there.

Update: Talked too soon, locking to a single core has helped, but things still stutter on occasion.

Grr, I hate when a little brainwave fixes some massive problem I've had for weeks.

In this case it's my new laptop (running Debian testing) where I had VMware running until I upgraded to 2.6.24, fair enough, the VMware guys seem to have decided that maintaining a large amount of external modules makes more sense then using internal functions (mainly the network layer, I can't see why tun/tap is so hard for them to understand).

While I was waiting for an update (and before I discovered that the correct answer is to use a third party patch...) I tried KVM which worked excellently except for some UI issues in Qemu.

It turns out that if you have the KVM module (in my case kvm-intel) loaded VMware will hang the machine hard when you try and boot a guest.

That, and the fact that the only way I can quit vmware is to use xkill because "File->Quit" (or the window close button) only closes the running VM, but never VMware itself.[1]

Those things just make me glad I'm only trialling VMware at the moment, I'll probably not bother buying until they've fixed at least the quit bug. If they can work out how to coexist with KVM then I might use KVM for linux guests, but keep VMware for the occasional Windows or MacOS X guest.

1: And yes, I'm using the included GTK, not the system one, it helps, but not much.