Abstract:
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Communication latencies have been identified as one of the
performance limiting factors of message passing applications in clusters of
workstations/multiprocessors. On the receiver side, message-copying operations
contribute to these communication latencies. Recently, prediction of MPI
messages has been proposed as part of the design of a zero message-copying
mechanism. Until now, prediction was only evaluated for the next message.
Predicting only the next message, however, may not be enough for real
implementations, since messages do not arrive in the same order as they are
requested. In this paper, we explore long-term prediction of MPI messages for
the design of a zero message-copying mechanism. To achieve long-term
prediction we evaluate two prediction schemes, the first based on graphs, and
the second based on periodicity detection. Our experiments indicate that with
both prediction schemes the buffer addresses and message sizes of several
future MPI messages (up to +10) can be predicted successfully. |