Abstract: This paper describes a hybrid methodology (based on both actual and synthetic reference streams) to produce traces representing significant complete workloads. By means of a software approach, we generate traces that include both user and kernel references starting from source traces containing only user references. We consider the aspects of kernel that have a deeper impact on the multiprocessor performance by (i) simulating the process scheduling and the virtual-to-physical address translation, and (ii) stochastically modeling the kernel reference stream. The target system of our study is a shared-bus shared-memory multiprocessor used as a general-purpose machine with a multitasking operating system.