how determinate the best value of processes parameter

Helloin RDBMS 11.2.0.3 exists a select to determiate the best value for parameter processes
now I have this parameter

SELECT name, value
FROM gv$parameter
WHERE isdefault = 'FALSE';

NAME                           VALUE
------------------------------ ------------------------------
processes                      150
nls_language                   ITALIAN
nls_territory                  ITALY
nls_date_format                DD-MON-RR
memory_target                  1677721600
control_files                  /opt/oracle/oradata/age2/contr
                               ol01.ctl, /opt/oracle/oradata/
                               age2/control02.ctl

db_block_size                  8192
compatible                     11.2.0.0.0

NAME                           VALUE
------------------------------ ------------------------------
db_recovery_file_dest          /opt/oracle/fast_recovery_area
db_recovery_file_dest_size     4322230272
undo_tablespace                UNDOTBS1
remote_login_passwordfile      EXCLUSIVE
db_domain                      agecontrol.it
dispatchers                    (PROTOCOL=TCP)(DISPATCHERS=3)
shared_servers                 30
max_shared_servers             50