Parallel Computer Architecture

202

CHAPTER

4 Workload-Driven Evaluation

30

r

25

W=130

N = 258

Λ/=514

W= 1,026

3

T3

30

25

20

15

10

Origin—16

K

Origin—64

K

Origin—512

K

Challenge—16

K

Challenge—512

K

7

10 13 16 19 22 25 28 31

Number

of

processors

(a) Ocean

on

Origin2000

Q^l

I I I I I I I I I I I

1

I I I I I I I I I I l I f I I I I I

1

4 7 10 13 16 19 22 25 28 31

Number

of

processors

(b) Barnes-Hut on

two

machines

FIGURE 4.1 Impact

of

application parameters

on

parallel performance.

For

Ocean,

the

applica-

tion parameter shown

is the

number

of

grid points

(N) in

each dimension, while

in

Barnes-Hut

it is the

number

of

bodies. These parameters determine

the

size

of

the data

se