Opcodes one can use to read time values are:
elapsedcycles
elapsedtime
eventcycles
eventtime
readclock
rtclock
timeinstk
timeinsts
times
timek
You can obtain the system date using:
date - Returns the number seconds since 1 January 1970.
dates - Returns as a string the date and time specified.
You can also set up counters using clockoff and clockon.