Figure 9-10 Performance benefits from a rational choice of SMT mode for the sp.C benchmark Figure 9-11 Performance benefits from a rational choice of SMT mode for the ua.C benchmark Many NPB applications benefit from SMT-4 mode. Therefore, from the general system  management perspective, it can be unwise to restrict users to lower SMT values. The  administrator should consider the following recommendations: 3 This recommendation is targeted at applications that are limited only by the computing power of a processor. It  does not account for interaction with the memory subsystem and other devices. At some supercomputing sites and  user environments, it can be reasonable to use a socket or even a server as a unit of hardware resource allocation. Chapter 9. Measuring and tuning applications  269 Choosing the SMT mode for computing nodes GLYPH<SM590000> Run the system in SMT-4 mode by default. GLYPH<SM590000> Let the batch scheduler turn on SMT mode on a per job basis. GLYPH<SM590000> Use a processor core as a unit of hardware resource allocation.