How large is the message header for interprocessor messages?
The message header requires 64 bytes for all messages. • What binary format is used for data storage in files? The DEC Alpha uses the little endian format. • 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 cause
