Scalable Cluster Software
MPI Latency
- We heard: 33 MHz to 66 MHz decreased latency from 5 to 4 us
- We cannot do much better than thatwith PCI (and I take 3 us for the example)
- Bill Camp gives us 3000 CPU clocks as maximum acceptable latency
- 3 us, 3000 clock cycles -> 1 ns clock cycle
- But CPUs will be faster than 1 GHz(good luck that he did not say 3000 instructions as max. latency)
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- COTS will not fulfill our latency needs