Computer Laboratory – Course material 2007–08: Comparative Architectures

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Comparative Architectures

Lecturer: Dr R.D. Mullins

No. of lectures: 16

Prerequisite course: Computer Design

Aims

This course examines the techniques and underlying principles that are used to design high-performance computers and processors. Particular emphasis is placed on understanding the trade-offs involved when making design decisions at the architectural level. A range of processor architectures are explored and contrasted. In each case we examine their merits and limitations and how ultimately the ability to scale performance is restricted.

Lectures

Introduction. The impact of technology scaling, market trends and application characteristics. Power and performance metrics. Environmental impact.
Review. Instruction-set principles; the scalar pipeline
Overview of architectural techniques. Classification of approaches; examples and pitfalls; Amdahl's law
Advanced Pipelining. Pipeline hazards; exceptions; branch prediction; avoiding branches; fetch issues; trace cache; limitations of pipelining and optimal pipeline depth [2 lectures]
Superscalar techniques. Instruction-Level Parallelism (ILP); static and dynamic scheduling; register renaming; load/store instruction ordering; advanced speculation techniques; example microarchitectures [2 lectures]
Software approaches to exploiting ILP. VLIW architectures; dynamic binary code translation; exploiting compiler hints
Multithreaded processors. Coarse-grained, fine-grained, SMT
The memory hierarchy. Caches; programming for caches; prefetching; software managed memories; main memory [3 lectures]
Vector processors. Vector machines; short vector/SIMD instruction set extensions; stream processing
Chip multiprocessors. Examples of multi-core processors; Memory, interconnect and programming challenges; performance limits
Special-purpose architectures. Converging approaches to computer design
Review and current developments

Objectives

At the end of the course students should

understand what determines processor design goals.
appreciate what constrains the design process and how architectural trade-offs are made within these constraints.
be able to describe the architecture and operation of pipelined and superscalar processors, including techniques such as branch prediction, register renaming and out-of-order execution.
have a basic understanding of vector, multithreaded and multi-core processor architectures.
for the architectures discussed, understanding what ultimately limits their performance and application domain.

Recommended reading

* Hennessy, J. & Patterson, D. (2006). Computer architecture: a quantitative approach. Elsevier (4th ed.) ISBN 978-0-12-370490-0. (3rd edition is also good)

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