Hosts with Hyperthreading enabled - better VM performance?

[sssstew]

After being involved in a recent thread about enabling Hyperthreading on your hosts :-

http://communities.vmware.com/message/1567821

Within that thread Jason comments that when HT is enabled he has seen much better performance of the VMs on that host, we i beleive i have also seen this. We have seen a definite improvement in performance of our Oracle server when its on a host which has HT enabled, so much so that we have now diabled DRS for this VM so that it doesnt get moved off them.

So has anyone else seen this marked improvement?

The spec of the hosts within our farm are largely the same, and the new hosts with HT could actually be classed as lower spec than our other hosts so its interesting this makes such a difference.

Anyway, interested to see what other people have found.

[thakala · Accepted solution]

Yes, hyperthreading on Nehalem class CPUs do improve vSphere performance a quite bit, doubling number of execution threads will make ESX scheduler job so much easiers. I have some stand alone ESX hosts with just single Quad Core Nehalem CPU for Oracle applications and performance is very good.

[sabya1232003]

My personal Experience says ..HT enabled is a great thing for the VMs with Multiple vCPUs.The CPU wait interval is reduced and sufficient CPU threads are available for multiple process execution.Its recommended to have HT enabled on ESX Servers.

[sssstew]

hmm yes interesting eh. shame we havent got HT accross all our hosts!