VM only sees 2 processors in Task Manager on Dual Quad-Core ESXi

[darkfriend]

I'm using ESXi 4.0 on Intel ICH7 board.

ESX server sees 2 PCPUs and 8 vCPUs (no hyperthreading). It's a dual-quad 2.5Ghz system.

I have assigned 4 vCPUs to a VM prior to install and installed XPx64.

After install, Task Manager shows only 2 processors.

The Device Manager shows 4 processors.

The Device Manager shows ACPI Multiprocessor x64-PC

When I max the CPU in the VM the ESX maxes at 5GHz used out of 20GHz maximum, so only 2 cores are being utilized by the VM.

I installed VM tools and reboot - no change.

I reinstalled ACPI driver - no change.

I checked the mobo BIOS and all the VT type settings are enabled, which is how I was able to get the ESXi to see 8 procs in the 1st place.

I connected the ESXi to a vSphere server and installed XPx64 using 8 processors.

Still the VM shows 2 processors in Task Manager, and now 8 in Device Manager.

Is there some limitation I'm unaware of. I tried a 2nd server with ESX 4.0 (not ESXi) and it exhibits the same behavior on a dual-dual processor (4 physical).

I have no idea what the problem is. I know XPx64 supports more than 2 processors as I have installed directly on the board which ESX is installed and achieved 8 processors in Task Manager.

Does anyone have any more ideas? Thanks.

[ShaneWendel · Accepted solution]

I believe XP Pro only supports two physical sockets, although it will recognize additional cores (or HT). There is a parameter you can change to set to have your vCPUs to appear as cores rather than seperate socketed CPUs.

http://www.yellow-bricks.com/2009/06/04/per-processor-licenses-for-your-application/

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Shane Wendel, VCP

http://fatalsync.wordpress.com

[darkfriend]

Great. That worked! I didn't see that in the manual.

I added that parameter and it worked right away. I have the VM vCPU set to 4. When the added parameter value is set to 2, I see 2 processors with 2 processor cores (4 total). When the parameter value is set to 4, I see 1 processor with 4 processor cores (4 total). When the parameter value is set to 1, I see 2 processors with 1 processor core (2 total). This shows that XP does in fact have a 2 processor SOCKET limit. So having two processors SOCKETS to deal with, and 4 vCPUs being the max for ESXi, I set the parameter value to 2. So now I have 2 dual core processors and Task Manager shows 4 processors. Each VM can use 10GHz (4 x 2.5GHz). I see that it is spreading the 50% total CPU usage of ESX Server (by the 100% usage of the VM) across all 8 cores though, so that's a good thing.

In ESX when vCPU is set to 8, it then showed all 8 in Task Manager, regardless of the parameter value setting, and the VM used 20GHz. So this would indicate that when the cores per socket value was 4, I had 2 quad cores, set to 2 I had 4 dual cores, and set to 1 I had 1 octacore. So currently XP can support 16 processors with the dual quad core with hyper-threading, which I've seen on physical machines, but on VM you will need ESX Enterprise Plus with 8-way vSMP support to get just 8 into the OS. All other (every other) edition would only support 4 processors per VM (4-way).

Thank you for your knowledge on the matter.

Message was edited by: darkfriend