Embodiments are directed to a heterogeneous system for dynamically mapping library calls to one of a plurality of processing platforms. The plurality of processing platforms include a central processing unit (CPU) and one or more acceleration units as co-processing units. The system includes an interposer configured to intercept the library calls from an application programming interface (API) and to map the library calls to one of the plurality of processing platforms according to a classification scheme based on an affinity table. The affinity table includes call signatures representing input parameters of sample library calls. Furthermore, the affinity table includes one or more performance parameters of the sample library calls for each of the processing platforms. The performance parameters indicate the performance of the sample library calls on the respective processing platform. Also included are a related method and a related computer program product.