Issue was due to many request were present in Master info provider and sales Related InfoProvider therefore DTP load was slow because the operations on these request administration tables was slow....
Program "RSSM_REDUCE_REQUESTLIST " was used to reduce the Request for DSO and CUBE.
and Programm "RSSM_AUTODEL_REQU_MASTER_TEXT" was used to reduce request from Master InfoProviders.
Request if needed again can be expanded using report RSSM_EXPAND_REQUESTLIST.
And reduced the sizes of these tables had positive impact on the performance.