gistfile1.txt

# I've got a shell for testing:
testshell $ echo $$
2133

# From a second shell, I'll instrument every instruction, function entry,
# and function return in the first shell, which is about 142,000 probes:
tracer $ dtrace -ln 'pid2133:a.out::' | wc -l
  142008
tracer $ dtrace -n 'pid2133:a.out::{ @ = count(); }' 
dtrace: description 'pid2133:a.out::' matched 142007 probes

# Now I'll run this loop in the first shell:
testshell $ time for ((i = 0; i < 10000; i++)) { :; }
real	3m38.393s
user	3m28.516s
sys	0m0.300s

# Here's the full output from the second shell:
tracer $ dtrace -n 'pid2133:a.out::{ @ = count(); }' 
dtrace: description 'pid2133:a.out::' matched 142007 probes
^C

        161566411

# That's 161566411 probes executed in 218.393s, for about
# 1352 nanoseconds per probe.