Dave, I think I know the reason, or at least part of the reason, for these spikes. As an example, when we select between the different protocols to use to exchange the message between peers, we only use predefined lengths, and we completely disregard buffer alignment.
I was planning to address this issue, by selecting a small, eager and pipeline size fragment also based on the alignment of the remaining buffer, in such a way that we minimize the non-aligned transactions across the PCI bus. Unfortunately my schedule for the next month looks grim, I don't think I would have the opportunity to play with the code. George. On Thu, May 4, 2017 at 4:22 PM, Dave Turner <drdavetur...@gmail.com> wrote: > I don't see anything in NetPIPE itself that could cause this as non > factors > of 8 are still aligned to 8 bytes. Can you think of anything in OpenMPI > that > would result in the message being treated differently when the message size > is not a factor of 8? The sends/recvs all use a data type of MPI_BYTE > in NetPIPE. >
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