page faults counter example is broken?!

[Thomas Knauth]

Dear list,

the system tap examples include a page fault counter. However, I've
noticed that it's way off with the number of page faults it records. A
simple

# stap -c df pfaults.stp

records about 20 page faults (minor and major). A simple cross-check with

# \time df

shows that it should report ~270 page faults.

What am I missing?!

Thanks,
Thomas.