A method for creating workload model to test performance of a critical application in a data processing network (112) is disclosed. The method includes receiving (202), at one of the plurality of data processing units (114a), an activity log with a plurality of entities from the data processing network (112). The method further includes creating (204) a transaction log of all transactions conducted using the activity log. Further the method determines (206) a plurality of transaction metrics using the transaction log, wherein the plurality of transaction metrics comprises an average transaction response time, a transaction throughput etc. The method further creates a workload model to test the critical performance of an application in the data processing network (112) based on the plurality of transaction metrics and provide effective performance test strategies.