
622 CHAPTER 8 Directory-Based Cache Coherence
i i. i i i r i i i r i i i i i i i i i i i i i i i i ti i i i
13 5 7 9 1113151719 212325
27 29 31
Number of processors
600,000
S 500,000
£ 400,000
j§ 300,000
E
2
200,000
100,000
Naive
TC
Naive
MC
TC
MC
I I M I 1 I I I I I I I I I I I 1
3 5 7 9 1113151719 212325272931
Number of processors
FIGURE 8.23 Scaling of speedups and number of bodies simulated under different scaling
models for the Barnes-Hut galaxy simulation on the Origin2000. As with the results for bus-based
machines in Chapter 6, the speedups are very good under all scaling models, and the number of bodies
that can be simulated grows