| Summary: | We describe the design and implementation of MPI-NP, a Myrinet communication system tailored
to support LAM, a public domain version of MPI. The goals of MPI-NP are to reduce the time spent
on the host for message processing, and to promote the overlap of computation and communication.
MPI-NP achieves these goals by off-loading as much of the computation as possible to the network
processor. MPI-NP relieves the host of several tasks, making more CPU cycles available to the
application, but pays a price for heavy utilization of the slower network processor, by adding a
significant overhead to message latency. Although part of the overhead can be attributed to the
hardware of our testbed, the philosophy of MPI-NP characteristically does not provide the best
latency possible because of performance disparities between host and network processors. Users
are left with the choice of deciding on the trade-off of latency versus host overhead. Applications
which are not latency bound can expect to perform well on MPI-NP.
|
|---|
