lat_tcp(8) measure interprocess communication latency via TCP/IP


lat_tcp -s

lat_tcp [ -m <message size> ] [ -P <parallelism> ] [ -W <warmups> ] [ -N <repetitions> ] hostname

lat_tcp -S hostname


lat_tcp is a client/server program that measures interprocess communication latencies. The benchmark passes a message back and forth between the two processes (this sort of benchmark is frequently referred to as a ``hot potato'' benchmark). No other work is done in the processes.

lat_tcp has three forms of usage: as a server (-s), as a client (lat_tcp localhost), and as a shutdown (lat_tcp -S localhost).


The reported time is in microseconds per round trip and includes the total time, i.e., the context switching overhead is includeded. Output format is like so

TCP latency using localhost: 700 microseconds


Funding for the development of this tool was provided by Sun Microsystems Computer Corporation.


Carl Staelin and Larry McVoy

Comments, suggestions, and bug reports are always welcome.