The script below can be used to monitor the free buffer waits in Oracle database: -

Free Buffer Waits SQL

SELECT state, sid, seconds_in_wait
FROM v$session_wait
WHERE event='free buffer waits'
ORDER BY seconds_in_wait DESC;

If the result returns with a high number seconds_in_wait, then you might need to take action recommended as below:-
a) Increase the db_block_lru_latches (rule of thumbs is 2 db_block_lru_latches for each CPU)
b) Increase the database buffer cache