I have a stored procedure that collects information for around 4-5 million records( on a monthly basis).
The way I have used is as below.

create or replace procedure monthly_report(report_Date date) is
v_start_date date;
v_end_date date;
C_LIMIT PLS_INTEGER := 100000;
type monthly_record is RECORD
(
--declarations here for the columns.
);
type tab_month_rec is table of monthly_record;
v_tab_month_rec tab_month_rec;
i number;
INDX number;
cursor example_cursor(start_date date, end_date date) is
select c1,c2,c3 from
t1,t2,t3,t4
where
date_of_record> start_date and date_of_record < end_date
--and all the join conditions here
;

begin
dbms_output.put_line('Monthly Report Execution starts');
-- logic for calculating start_date and end_date
i := 0;
open example_cursor(v_start_date,v_end_Date);
LOOP
i:=i+1;
DBMS_OUTPUT.PUT_LINE('Loop no:'||I);

FETCH example_cursor
BULK COLLECT INTO v_tab_month_rec
LIMIT C_LIMIT;
EXIT WHEN v_tab_month_rec.COUNT = 0;

FORALL INDX IN 1 .. V_TAB_MORT_LOANS.COUNT
--DML statement here
END LOOP;
COMMIT;
end monthly_report;

the above procedure as expected takes around 1 hour to complete.
but the problem is that the dbms_output.put_line messages come only after the stored procedure completes. I mean i get all the output only after 1 hour. Is there any way to see how much of the stored procedure is complete or rather get the dbms_output.put_line message as soon as it gets executed.

The output cannot be retrieved until the PL/SQL program unit from which it was buffered returns to its caller.