I have an ESX 4 (Dell R900 Quad-Quad) host that was upgraded from 3.5 to 4.0 and is now at build 244038 which seems to not be spreading the CPU load accross all of the cores and is causing the guest VMs vCPU usage to spike through the roof. "esxtop" shows 4 of the cores getting hammered while the rest just idle. There are only 3 VMs on that system (4 vCPU each) but it seems as if only one VM can be in service (web node) at a time. As soon as I put another VM in service, the CPU spikes on 4 of the 16 cores and both VMs' vCPU shoots through the roof. This is one of a dozen such R900 configurations all with 4-6 VMs on it and the only one that seems to do this. As soon as I migrate a problematic VM to another equally taxed host it performs without issue and esxtop shows what I would expect, namely that the cores have an pretty good distribution of the load.
I've upgrade the BIOS to the lates version and updated ESX to the latest build, but the issue keeps happening. In a post regarding understanding esxtop it mentions something about a possible load imbalance, but doesn't go into detail on how to correct this. Has anyone come across this issue before?
Thanks!
