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After the 262K study was completed, the AEDIF code was restructured
to remove all unnecessary tables and subroutines to permit
larger meshes with smaller executables than otherwise possible.
Table 12:
568K mesh: Globus performances on individual clusters - 16 CPUs -O3 option
| Run type |
Globus |
Globus |
Globus |
Globus |
| Name of cluster |
INRIA-nina |
IUSTI |
INRIA-pf |
CEMEF |
| Processor speed |
2 GHz |
2 GHz |
1 GHz |
1 GHz |
| LAN speed |
1 Gbps |
100 Mbps |
100 Mbps |
100 Mbps |
| cache |
512K |
512K |
256K |
256K |
| RAM/CPUe |
1/2 GB |
1 GB |
1/4 GB |
1/4 GB |
| Executable size |
237 MB |
237 MB |
237 MB |
237 MB |
| Number of processors |
16 |
16 |
16 |
16 |
| Total computational time |
104.0 |
94.4 |
195.6 |
189.7 |
| Local inter-comm. time |
1.8 |
13.3 |
12.2 |
13.4 |
| Global inter-comm. time |
51.5 |
39.1 |
55.9 |
81.5 |
| Computational ratio |
1.0 |
0.91 |
1.9 |
1.9 |
| Communication/Work |
1.0 |
1.2 |
0.5 |
1.0 |
|
Shown in Table 12 are the performances on
the different individual clusters using 16 processors.
The performances on the INRIA-pf and the CEMEF clusters are quite good (compute
ratio < 2). Note that the IUSTI cluster performance is 20 percent faster
than the INRIA-nina cluster, an unexpected result.
However, the Communication/Work ratios for the 568K mesh with 16 processors are
much larger than for the 262K mesh using 8 processors4. In examining the computational
times for the the 262K and 568K runs, it was found that different compile options were
used5and explains the differences in the Communication/Work ratios. Therefore for the same mesh,
the more efficient the code (less Work per processor) the larger the Communication/Work ratios as the
communication times depend on the LAN speeds that remain unchanged6!
Table 13:
568K mesh: Globus performances on individual clusters - 16 CPUs -O1 option
| Run type |
Globus |
Globus |
Globus |
Globus |
| Name of cluster |
INRIA-nina |
iusti |
INRIA-pf |
cemef |
| Processor speed |
2 GHz |
2 GHz |
1 Ghz |
1 GHz |
| LAN speed |
1 Gbps |
100 Mbps |
100 Mbps |
100 Mbps |
| cache |
512K |
512K |
256K |
256K |
| RAM/CPUe |
1/2 GB |
1 GB |
1/4 Gb |
1/4 GB |
| Executable size |
871 MB |
871 MB |
871 |
871 MB |
| Number of processors |
8-8 |
8-8 |
8-8 |
8-8 |
| Total computational time |
547.3 |
449.9 |
740.9 |
1039.8 |
| Local inter-comm. time |
2.3 |
12.8 |
9.4 |
12.5 |
| Global inter-comm. time |
280.8 |
178.9 |
288.7 |
277.3 |
| Computational ratio |
1.00 |
0.82 |
1.35 |
1.90 |
| Communication/Work |
1.07 |
0.74 |
0.67 |
0.39 |
|
Table 13 shows the performances
on the individual clusters
using the -O1 option. Comparison of Table 12 (-O3 option)
with Table 13 (-O1 option)
shows that compiling with the -O1 option reduces the Communication/Work time
ratios7.
Table 14:
568K mesh: inter-cluster performance - 16 CPUs -O1 option
| Run type |
Globus |
Globus |
Globus |
Globus |
Globus |
Globus |
| Name of cluster |
nina |
nina-pf |
nina-iusti |
nina-cemef |
pf-cemef |
iusti-cemef |
| Processor speed |
2 GHz |
2/1 Ghz |
2/2 GHz |
2/1 Ghz |
1/1 Ghz |
2/1 Ghz |
| Executable size |
343 MB |
343 MB |
343 MB |
343 MB |
343 MB |
343 MB |
| Number of processors |
16 |
8-8 |
8-8 |
8-8 |
8-8 |
8-8 |
| Total computational time |
547.3 |
702.3 |
1207.9 |
1322.4 |
1323.4 |
2041.6 |
| Local inter-comm. time |
2.3 |
10.5 |
496.3 |
190.8 |
181.9 |
554.0 |
| Global inter-comm. time |
280.8 |
279.5 |
449.2 |
411.4 |
411.4 |
449.4 |
| Computational ratio |
1.00 |
1.28 |
2.21 |
2.42 |
2.41 |
3.73 |
| Communication/Work |
1.07 |
0.70 |
3.61 |
0.83 |
0.81 |
0.97 |
|
Shown in Table 14 are some of the inter-cluster performances
with 16 processors. It is noted that the local communication times for nina-cemef and pf-cemef
are approximately two times smaller than the other inter-cluster combinations.
This astonishing observation cannot be explained.
Next: Influence of the "0"
Up: 568K mesh
Previous: 568K mesh
Stephen Wornom
2004-09-10