05-21-2012 08:01 AM - edited 05-21-2012 08:30 AM
Good day everyone,
I'm preparing for the installation of Performance Center and have a question regarding VM's and Hyperthreading. In the install guide for PC it states that hyperthreading must be deactivated and can be done in the bios. How does this work with a VM setup? If the VM server has hyperthreading enabled, does it work the same as if you have a single dedicated physical server or is it different since it's a VM and won't affect Performance Center like it would if it was a physical box?
Initially my inner tech nerd says "yes it sill affects it just like a physical box" but I'm not 100% knowledgeable about VM systems beyond the couple of VirtualBox instances I have on my local PC.
Thanks in advance!
05-28-2012 09:56 AM
I am not 100% sure on this, but I have setup like this and it does not affect it, VMs when created you can choose processors and type. Hyperthreading would affect the performance of the virtualized environment as but not on how it operates. It would be 2 different things.
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10-09-2012 10:37 AM
I am installing Performance center 11 , and all we have is VM servers only and as per sys admin hyper threading is enabled and they are not ready to disable it ,
Could you please let me know can i use VM server with Hyper threading enabled for pc 11 installations
10-09-2012 11:59 AM - edited 10-09-2012 12:01 PM
I believe that you may be confusing hyperthreading that is available at the ESX server level and Hyperthreading that is available to the guest OS level.
Hyperthreading at the ESX level should not cause a problem
If Hyperthreading is reported at the guest OS level this is not supported and according to the documentation must be disabled.
You would need to refer to the VMware documentation on how to disable Hyperthreading at the Guest OS level
Also remember that PC components (ALM, PCS, Host, SALG) do not have any code that allows them to be multi-CPU aware. There will be some residual benefit to having more than once CPU because the OS that is multi-CPU aware will be able to offload some of its processing off of the main CPU but Performance Center will not directly benefit from having more than 1 CPU.
10-10-2012 07:50 AM
Thanks for the reply , below is the response from my system administrator , do we have any alternative for this?
(As I mentioned by default, to maximize performance, hyper threading is enabled on all ESX and guest level within our environment.
Please keep in mind that by disabling hyper threading, we can adversely impact the performance on the VMs. With this setting, there can be cases where there is no core to which a descheduled virtual machine can be migrated, even though one or more logical cores are idle. This can lead to CPU starvation for the VMs.)
10-10-2012 08:37 AM
Hyperthreading at the guest level is not supported and must be disabled according to the HP PC Install Guide. If you continue leaving Hyperthreading enabled I am not sure what result you will get. However, if you run into problems support will ask you to try reproducing the problem on a system that does not have Hyperthreading enabled. If the problem does not recur with Hyperthreading disabled that will be your answer. If it does recur with Hyperthreading disabled then the case will be able to proceed but by then you have wasted all that time testing Hyperthreading.
I would suggest that you login to the HP Software Support site and submit an enhancement request for PC to fully support Hyperthreading. The more customers that make such a request will improve the chances of such a request being implemented.
Until R&D makes such a change I can only recommend that you disable Hyperthreading