This is xnu-10002.1.13. See this file in:
MPMMTest / KQMPMMTest

These tests measure the speed of IPC with mach messaging and kqueues. To build,
simply run make. A 32- and 64-bit version of each test will be generated by
default. Each test can be run without options:

$ ./MPMMtest
1 server, 4 clients per server (4 total) 400000 messages... in 4.820 seconds
  throughput in messages/sec:     82978.7
  average message latency (usec): 12.1

and will report the latency and throughput that the server achieved. The user
can change the number of servers and clients, the flavor of message, and other
variables with command line options--run './MPMMtest -h' for details.