by Deborah T. Marr, Frank Binns, David L. Hill, Glenn Hinton, David A. Koufaty, J. Alan Miller, Michael Upton
Desktop Products Group, Intel Corp.

Introduction

Intel's Hyper-Threading Technology brings the concept of simultaneous multi-threading to the Intel® Architecture. Hyper-Threading Technology makes a single physical processor appear as two logical processors; the physical execution resources are shared and the architecture state is duplicated for the two logical processors. From a software or architecture perspective, this means operating systems and user programs can schedule processes or threads to logical processors as they would on multiple physical processors. From a microarchitecture perspective, this means that instructions from both logical processors will persist and execute simultaneously on shared execution resources.

This paper describes Hyper-Threading Technology and discusses the microarchitectural details of Intel's first implementation on the Intel® Xeon® processor family. Hyper-Threading Technology is an important addition to Intel's enterprise product line and will be integrated into a wide variety of products.

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