1

EGRE 426

Handout 1

8/25/09

2

Preliminary• EGRE 365 is a prerequisite for this class.• Class web page http://www.people.vcu.edu/~jhtucker/f09-egre426/index.html

• Syllabus Grades:– Quizzes (2) 40%– Homework 10%– Laboratory 10%– Design Project15% – Final Exam 25%

• Text book Computer Organization and Design 3rd edition, Designers Guide to VHDL.

3

Computer Organization and Design

• This book and the slightly more advanced Computer Architecture a Quantitative Approach are the dominant computer architecture text books.

• Too big.– Chapter 1 – Read

– Chapter 2-7 – will be covered in detail skipping some material.

– Chapters 8-9 – Will depend on time.

– Supplement with additional material.

4

Introduction

• We will learn not just how computers work, but gain an understanding into how and why computers evolved into the current generation.

• Computer have undergone rapid changes.– Increasing performance– Decreasing cost

5

History

• Computers did not really begin until World War II.

• The widespread use of microprocessors began about 35 years ago.

• Personal computers were not taken seriously until the introduction of the IBM PC in 1981.

6

Computers have resulted in the information revolution.

• Agricultural revolution.– Several Thousand years.

• Industrial revolution.– Several Hundred years.

• Information revolution.– A couple of decades.

7

My History• I started at NASA in 1963 and worked in the

computer division.– At that time computers were very expensive and very

large.

– Programs were written on punched cards (one line per card) and fed into the computer.

– The state-of-the-art super computer that I worked with was capable of executing one million instructions per second, it cost several million dollars, and occupied the major portion of a large building.

8

My History continued

• In the 60’s I did early work in interactive computing techniques.– Forerunner of what we do today, but not

practical when it required a dedicated super computer connected to a display console.

• In 1974 I completed my PhD and started working with microprocessors.

9

Moore’s Law• One of the founders of Intel, Dr. Gordon Moore, observed

in 1965 that the number of transistors in an IC was doubling every year. He predicted that this would continue for a couple of decades and then slow to doubling every 18 months.

• This prediction has proved remarkably accurate. So much so that it has come to be expected, and Moore’s prediction has become known as Moore’s law.– It is worth noting that since Moore made his prediction the

consensus at any time has been that it would last for only about ten more years.

– Economics not technology may be what actually stops Moore’s law.

10

11

12

13

14

15

Single instruction stream – single data stream

16

Multiple instruction stream – multiple data stream.

17

Single instruction stream – single data stream

18

19

Definitions

Efficiency is the measurement of how close we come to achieving ideal speed up.

1

1

p

S

T

pT

E p

pp

20

21

Assumptions

• All operations take one unit of time.• All instructions and data are available when

needed.• i.e. We don’t have to wait for memory or

communication.• This is naïve and completely unrealistic, but

can be used to teach some fundamental truths.

22

Conventional uniprocessor (SISD)

T A1*B1 A2*B2 A3*B3 A4*B4 … An*Bn

1

2

3

4

5

6

23

Multiprocessor MIMD (unlimited processors)SIMD – same results.

T A1*B1 A2*B2 A3*B3 A4*B4 … An*Bn

1

2

3

4

5

6

24

Multifunction computer (2 * units)

T A1*B1 A2*B2 A3*B3 A4*B4 … An*Bn

1

2

3

4

5

6

25

SISD – single processor

T A1 A2 A3 A4 A5 An

1

2

3

4

5

6

n

n

ii AAAAP ...21

1

26

MIMD or SIMD – with unlimited processors

T A1 A2 A3 A4 A5 An

1

2

3

4

5

6

n

n

ii AAAAP ...21

1

27

Algorithm can effect speedup.SISD

T A (B C D + E) A B C D +A E1

2

3

4

5

6

AEABCDEBCDA )(

28

Algorithm can effect speedup.MIMD

T A (B C D + E) A B C D +A E1

2

3

4

5

6

AEABCDEBCDA )(

29

SISD Method A

T A0 + A1*X + A2*X*X + A3*X*X*X + A4*X*X*X*X

1

2

3

4

5

6

7

8

9

10

11

...432100

XXXXAXXXAXXAXAAXAPn

i

ii

30

SISD Method B

T A0 + A1*X + A2*X*X + A3*X*X*X + A4*X*X*X*X

1

2

3

4

5

6

7

8

9

10

11

...432100

XXXXAXXXAXXAXAAXAPn

i

ii

31

SISD Method C

T A0 + X ( A1 +X ( A2 + X ( A3 + X ( A4 + …))))

1

2

3

4

5

6

7

8

9

...))))((((

...

43210

432100

AXAXAXAXA

XXXXAXXXAXXAXAAXAPn

i

ii

32

MIMD unlimited processors

T A0 + X ( A1 +X ( A2 + X ( A3 + X ( A4 + …))))

1

2

3

4

5

6

7

8

9

...))))((((

...

43210

432100

AXAXAXAXA

XXXXAXXXAXXAXAAXAPn

i

ii

33

MIMD unlimited processors

T A0 + A1*X + A2*X*X + A3*X*X*X + A4*X*X*X*X

1

2

3

4

5

6

7

8

9

...432100

XXXXAXXXAXXAXAAXAPn

i

ii

34

SIMD unlimited processors

T A0 + A1*X + A2*X*X + A3*X*X*X + A4*X*X*X*X

1

2

3

4

5

6

7

8

9

...432100

XXXXAXXXAXXAXAAXAPn

i

ii

35

1)(log222

22)(loglog)(log)( nnnKnnT

K K K( ) , ( ) , ( )0 0 1 1 2 1

K i K i i( ) ( ) 2 2 3

Where,

And,for i > 2

A X A A X A X A X A Xii

nn

i

n

0 1 22

33

11

0

1

Using an MIMD machine with unlimited processors, the time to compute

is given by

For example when N = 9,

2

4 3 12

log 9 1 4 12 2

log 9 4, (4) (4 2) 2 (2) 2 2 2 4

(9) log 9 log 4 9 2 4 2 9 2

4 3 7

K K K

T

For N = 3000

T(3000)=23

36

Compute1

( ) *N

i ii

F N A B

using a SISD computer with a add-multiply arithmetic unit.

T(4) = 4

37

Pipeline examples

38

39

40

41

42

43

Using a four segment pipeline with the restriction that the pipeline must empty before a new type (add, multiply, etc.) of operation can begin.

T4(4) = 16 segment times.

44

Using a four segment pipeline which does not require that the pipeline empty before a new type of operation can begin.

T4(4)=15 segment times.