How to improve performance of the below code.

Question

Hello.
This below code is show 80% database performance in runtime analysis ( transaction SE30). I am using view KNA1VV for retrieving data using customer and sales area from selection screen.
Please advice how can I improve the performance of below code.
Fetch the customer details from view KNA1VV
  SELECT kunnr
         vkorg
         vtweg
         spart
         land1
         name1
         ort01
         pstlz
         regio
         stras
        INTO TABLE t_cust
        FROM kna1vv
  WHERE kunnr IN s_kunnr
  AND   vkorg IN s_vkorg
  AND   vtweg IN s_vtweg
  AND   spart IN s_spart
  AND   loevm = space
  AND   loevm_knvv = space.
  IF sy-subrc EQ 0.
    SORT t_cust BY kunnr.
  ELSE.
    w_flag = c_true_x.
  ENDIF.
Fetch customers for entered company code
  IF NOT t_cust[] IS INITIAL AND NOT s_bukrs IS INITIAL.
    SELECT kunnr
           FROM knb1
           INTO TABLE lt_knb1
           FOR ALL ENTRIES IN t_cust
    WHERE kunnr = t_cust-kunnr
    AND   bukrs IN s_bukrs
    AND   loevm = space.
Thanks,

Answer 1

80% is just a relation and must not be problematic, what about the absolute runtime, is that acceptable?
Also, your range S_KUNNR could contain anything from a single value (super fast) to nothing (probably slow, depends on number of entries in KNA1VV), so what do you expect here?
Thomas