1. CS170 Computer Organization and Architecture I
Ayman Abdel-Hamid
Department of Computer Science
Old Dominion University
Lecture 10: 9/26/2002
Lecture 10: 9/26/2002
CS170 Fall 2002

2. Outline Problem 2.15 Rates of Improvement Influences on Performance
Summary of performance tests
A look ahead (chapter 3)
Lecture 10: 9/26/2002
CS170 Fall 2002

3. Rates of Improvement F = (1 + R)N F improvement factor
R rate of improvement per duration (e.g., per year)
N number of durations (e.g., number of years)
For DRAMs, the component density increases 60% per year. What is the improvement factor in 3 years?
R = 0.60 N = 3
F = (1+R)N = (1+0.6)3 = 4.096
Lecture 10: 9/26/2002
CS170 Fall 2002

4. Influences on Performance
Execution time = IC * CPI * Cycle time
= IC * [CPU cycles per instruction + Memory cycles per instruction ] * cycle time
= IC * [CPU cycles per instruction + (References per instruction * cycles per reference) ] * Cycle time
Instruction
Set
Architecture
Compiler
Technology
CPU
Implementation
Cache and
Memory
Hierarchy
From “Cache and Memory Hierarchy Design”, S.A. Przybylski Morgan Kaufman Publishers, Inc. 1990
Lecture 10: 9/26/2002
CS170 Fall 2002

5. Performance Tests Kernels Synthetic Benchmarks
Small pieces of real programs, subroutines or inner loops. Examples Livermore (series of 21 small loop fragments) loops and Linpack (portion of a linear algebra subroutine package). Very popular for benchmarking scientific applications.
Can overstate performance of real applications
Synthetic Benchmarks
Whetstone and Dhrystone
Small and Simple benchmarks
Small and simple codes embodying a single well known algortihm. An example is a Quicksort code. They are too simple and too restricted in operations to test performance.
Mixtures of real programs
SPEC
Lecture 10: 9/26/2002
CS170 Fall 2002

6. A Look Ahead Chapter 3 Overview of computer organization
Fetch/Execute cycle
Computer operations
addressing modes
Instruction set design principles
Overview of MIPS architecture
Stored program concept
Learn a subset of MIPS assembly language
Show how MIPS instructions are represented in machine language
Contrast MIPS architecture with other (I80X89 and PowerPC architectures
Lecture 10: 9/26/2002
CS170 Fall 2002