... | ... | @@ -125,10 +125,26 @@ Some traces, with 4 ranks, 1 rank/socket, B = 4, T=1024 |
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![mpi_comms.code_legend](uploads/b2a0c1e1c7f98529751cbe14084768aa/mpi_comms.code_legend.png)
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Communication cost with number of ranks :
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Communication cost with number of ranks (1rank/socket, B=4*worldsize, T=1024) :
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| Number of ranks | Communication time from last to first | Communication time from first to last |
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| ------ | ------ | ------ |
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| 2 | 100 ms | 180 ms |
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| 4 | 70 ms | 100 ms |
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| 8 | 150 ms | 300 ms |
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| 16 | 175 ms | 300 ms |
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As you can see, we have a better communication time with 4 ranks. This is because we can adjust the communication block's sizes. Currently, the size have been manually adjusted for 4 ranks, explaining why the best communications time have been set for 4 ranks.
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# Increasing the number of ranks
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With B=16, T=1024, 1 rank/socket
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| Number of ranks | time/iteration |
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| ------ | ------ |
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| 1 | 67000 ms |
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| 2 | 31500 ms |
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| 4 | 150 ms | 15000 ms |
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