hi,
SMON does the following primary functions
1. Instance Recovery at startup
2. Coalescing space in tablespaces
3. Cleaning up temporary segments
i feel that uer problem lies in point no. 3., if uer application has generated a temporary segment very large and that needs to be cleaned after its use then SMON will have to consume excessive resources since the temporary segment has grown very large,
pls. check up the size of uer temp. segment and confirm , shall advice further
cheers
soren