> If it does plain RDTSC, it may not be fine.
I'm a little surprised how easily it happens with plain rdtsc on my hardware: https://gist.github.com/jcalvinowens/4c0c25e753f8ce2d0a6ca48...
# time ./a.out a.out: local=4692633034088164 < remote=4692633034088165 real 0m0.025s