Daily Archives: 21st July 2010

Hyper-threading on VMware vSphere 12

enter site Hyper-threading : Hyper-threading is an Intel-proprietary technology used to improve parallelization of computations. For each processor core that is physically present, the Operating System  addresses two logical processors, and shares the workload between them when possible. With Hyper-threading a single processor core can execute two independent threads simultaneously . Performance improvements on hyper-threaded machines are dependent on the application and work loads . We might see slight performance improvements in certain applications while certain application performance might degrade as cache is shared between logical processors . To enable or not to enable Hyper-threading on Hypervisor hosts has always been a debatable question with no clear winners .  HT cannot double the performance of a processor but it can certainly help in improving the performance slightly depending on the work load . I have tried to consolidate and mention some considerations that would help administrators decide if to enable / disable  HT . Hyper-threading has to be enabled in BIOS as well as in ESX . By default , HT is enabled in ESX ESX can intelligently determine if a system  is enabled for hyper-threading and can load balance evenly across all cores of a processor. Logical processors or threads on the same core will […]