Hi
1.Try to divide your load based on time period.
2. check some where in process chain same data target is loading through another process try to schedule time of load so that lock can not be set.
3. search with improve the loading performance in sap bi.you will get lot of info
4. a)you can see the process chain run time statistic using technical content if it is installed.
Please check query which will show you runtime of process chain.
b) you can check in following table also
RSPCLOGCHAIN, RSPCPROCESSLOG
Regard,
Ganesh Bothe