V$MUTEX_SLEEP shows the wait time, and the number of sleeps for each combination of mutex type and location.

Column Datatype Description
MUTEX_TYPE VARCHAR2(32) Type of action/object the mutex protects
LOCATION VARCHAR2(40) The code location where the waiter slept for the mutex
SLEEPS NUMBER Number of sleeps for this MUTEX_TYPE and LOCATION
WAIT_TIME NUMBER Wait time in microseconds