Scott Drummonds on Virtualization

Optimizing vSphere for Hyper-threading


VMware’s Jeff Buell has been looking into High Performance Computing (HPC) in support of a new addition to the office of the CTO.  Jeff just posted an article on VROOM! showing outstanding memory bandwidth in vSphere virtual machines.  No one should be surprised by this–virtual machine memory bandwidth has rarely been a problem.  But Jeff did discuss a advanced configuration parameter that should pique everyone’s curiosity: NUMA.preferHT.

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vSphere 4.0, Hyper-Threading, and Terminal Services


I recently wrote a blog article detailing Hyper-Threading (HT) and its effect on vSphere.  An astute reader pointed out, a recent update to Project VRC‘s terminal services analysis suggests disappointment with HT on vSphere.  We spent a lot of time looking at those results to understand why they contradicted the body of performance data, which show HT offering 10-30% gain on vSphere. What we discovered led us to create a vSphere patch that would allow users to improve performance in some benchmarking environments.

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Hyper-Threading on vSphere


I continue to receive many questions from our customers on the expected performance gains of the new version of Hyper-Threading in Intel’s Core i7 processors. The answer requires a little bit of discussion on Hyper-Threading, a little bit on ESX, and comes with some performance data. If you are still interested, read on.

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