Can message passing be used to communicate with processors external to Cplant?
MPI is supported as a message-passing library on the compute partition of Cplant, but off-machine connections for applications running on the compute partition are not currently supported, but are planned. • What can I do to improve message passing performance? Make sure the buffer you are sending from or receiving into is 4 or 8 byte aligned, i.e. the two least significant bits (LSB) of the buffer address are 0. Make sure your message length is a multiple of 4. Send large messages to amortize message startup overhead. • Are there any known problems with the message passing? The low-level Myrinet driver cannot currently send 1 and 2 byte messages that do not start or end on a 4 byte boundary. The Myrinet hardware has a built-in 4 second timer that causes a network reset, when a message transfer takes longer than that time. While that is enough time to transfer all the physical memory of our nodes, it can cause problems in case of network contention. For example, when all the nodes in a
