Hardware software co-design seeks to meet performance objectives via a combination of hardware and software modules. One difficulty in reaching these objectives lies in lack of cohesion and increased coupling amongst the implemented modules that results in an increased inter module communication cost. While most of the traditional partitioning approaches are initiated in the post coding phase, we suggest the design stage may be a better focus of attention in addressing this problem. In this paper, we propose a novel approach that uses information from sequence diagrams in UML designs to help ease the partitioning problem.