Hyperthreading Technology

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HYPER-THREADING

TECHNOLOGY

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Abstract

Hyper-Threading technology was first introduced on the Intel Xeon

processors.

In November 2002, Intel launched this technology on the Intel Pentium 4

at clock frequencies of 3.06 GHz and higher, making the technology

widely available to the consumer market.

This Technology brings the concept of simultaneous multithreading to the

Intel architecture. It describes how Intel made a single physical processor

appear as multiple logical processors.

Users can get a 25-percent boost in performance from a technology that

costs less than 5 percent in added die area.

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Abstract

This Technology illustrate the importance of choosing the right sharing

policy for each shared resource.

This is done by examining and comparing three different sharing

policies they are partitioned resources, threshold sharing, and full

sharing.

The choice of policy depends on the traffic pattern, complexity and size

of the resource, potential deadlock scenarios, and other considerations.

Finally, it describes how this technology significantly improves

performance on several relevant workloads.

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Contents

Introduction Problem statement

Existing System

Proposed System

Advantages of current system

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Introduction

Hyper-Threading (HT) Technology is ground breaking technology from

Intel that allows processors to work more efficiently.

This new technology enables the processor to execute two series, or

threads, of instructions at the same time, thereby improving performance

and system responsiveness while delivering performance for the future.

Intel Hyper-Threading Technology improves the utilization of onboard

resources so that a second thread can be processed in the same

processor.

Hyper-Threading Technology provides two logicalprocessors in a single

processor package.

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Introduction

Basics Of Hyper-Threading Technology:

Intel's Hyper-Threading Technology duplicates certain sections of the

processor, specifically those areas that store the CPU's architectural state

and not the main execution resources.

By processing only the architectural state, Hyper-Threading is able to

make the processor appear as if dual processors are available.

As this process occurs, Hyper-Threading allows the operating system to

schedule two threads or processes simultaneously through each processor.

The technology utilizes simultaneous multithreading and is used to increase

both throughput and energy efficiency

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Introduction

Working Of Hyper-Threading Technology:


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System Architecture

Processors without Hyper-Threading Tech Processors without Hyper-Threading Tech

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Problem Statement

The amazing growth of the Internet and telecommunications is powered by

ever-faster systems demanding increasingly higher levels of processor

performance.

To keep up with this demand we cannot rely entirely on traditional

approaches to processor design.

Microarchitecture techniques used to achieve past processor performance

improvement. In fact, transistor counts and power consumption are

increasing at rates greater than processor performance.

Processor architects are therefore looking for ways to improve performance

at a greater rate than transistor counts and power dissipation.

Intels Hyper-Threading Technology is one solution.

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Existing system

Using more than one processor in a system directly provided thread levelparallelism. But this was a costly solution and required special on board

support for multiple processors.

These systems also required some type of synchronizing mechanism. The

overhead for this synchronizing and the frequent collision for the need of

resources slowed down such implementations considerably.

Hyper-threading, introduced by Intel provided by Intel provided the

solution for this problem, but also provided its own challenges.

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Proposed System

Hyper-Threading is Super-threading without the restriction that eachpipeline stage or clock cycle must contain instruction form the same thread.

Vacant execution slots in each pipeline stage is filled by instruction from

another thread, enabling thread level parallelism.

This can be done as long as there is no collision of resources required by

two threads.

In processors with Hyper-Threading Technology, a single processor core

executes these two threads concurrently.

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Advantages of Current SystemBy using Hyper-threading Technology the advantages are:

Improved overall system performance.

Increased number of users a platform can support.

Improved reaction and response time because tasks can be run on separate

threads.

Increased number of transaction that can be executed.

Compatibility with existing IA-32 software.

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Conclusion

IntelsHyper-Threading Technology brings the concept of simultaneous

multi-threading to the Intel Architecture.

This is a significant new technology direction forIntels future processors.

It will become increasingly important going forward as it adds a new

technique for obtaining additional performance for lower transistor and

power costs.

Intel Xeon Hyper-Threading is definitely having a positive impact on Linux

kernel and multithreaded applications.

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Hyperthreading Technology

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