If you are running the x11perf benchmark when the default server visual is 24-bit TrueColor, the -shmput<nn> tests will fail. This is because this test requires more shared memory than that provided by the default shmsys configuration. The X11R5 version of x11perf version will core dump, while the X11R6 version will report an error and make no measurement.
To run this test, you will need to increase the amount of shared memory.