bpi_latency [-a address ] [-u unit number] [-c channel] [-m message size] [-n number of messages]
bpi_latency measures host-to-host latency using the Myrinet BPI. You should not use this program. To measure host-to-host latency use the program api_latency, which uses the Myrinet API.
bpi_latency is a ping-pong test between two hosts using the Myricom MCP and the Myrinet BPI. You set the number of transfers with number of messages . bpi_latency divides the time it took to run the test by the numbers of transfers to get an average round-trip latency between two hosts. To use bpi_latency you first start up the receiver. The receiver does not specify address. Then you start up the sender, giving as the address parameter the address of the receiver. So you should experiment with various numbers of messages.
The destination address parameter (-a) is a 64-bit LANai board address, in the same format as that returned by the l3prom program. You can leave off leading zeros.
| freja 31% bpi_latency -u 0 -c 1 -m 4 |
metis 1% bpi_latency -u 0 -c 1 -m 4 -a 8 -n 500 208 micro seconds round trip of 4 bytes. metis 2% |