As Flamingo said, it is total gross wages:
See page 5 & 6 of
https://www.ssa.gov/pubs/EN-05-10069.pdf where it says:
"We do count an employee’s contribution to a pension or retirement plan, however,
if the contribution amount is included in the employee’s gross wages."
Remember that any benefits not paid are not "lost", they are deferred until you reach FRA, or wages go below the limit.