What is Hyperthreading Future Silicon Chips Computer Technology Linux Development Tools Performance Analysis Software : Recent advances in silicon technology have changed the trade-offs in micro-processor architecture. Larger transistor counts have facilitated the design of Hyper-Threading Technology (HT Technology) and multi-core processors. A processor with HT Technology can provide two logical processors in one physical core.

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Introduction
by Gail Lyons

Recent advances in silicon technology have changed the trade-offs in micro-processor architecture. Larger transistor counts have facilitated the design of Hyper-Threading Technology (HT Technology) and multi-core processors. A processor with HT Technology can provide two logical processors in one physical core. The physical resources of the core are shared between the two logical processors, and the state information that is needed to support each logical processor is duplicated. Applications rarely consume all of the physical resources of a core, so HT Technology enabled cores can improve the performance of many applications.

Multi-core technology places more than one core in a physical package. Multi-core processors may have a shared cache between its cores, or have a dedicated cache topology for each core. The performance characteristics of HT Technology and multi-core processors depend on processor topology and its cache topology on the platform. Optimal performance of multithreaded software requires effective management of shared and dedicated resources available to each logical processor.

Although the processor and cache topology in a modern platform are more complex than those of a traditional symmetric multi-processor design, this paper will demonstrate a detailed algorithm of enumerating processor topology. It will also show how to bind a thread to a specific processor under a Linux environment.