In this paper, we use knowledge-based control theory to monitor global properties in a distributed system. We control the system to enforce that if a given global property is violated, at least one process knows this fact, and therefore may report it. Our approach uses knowledge properties that are precalculated based on model checking. As local knowledge is not always sufficient to monitor a global property in a concurrent system, we allow adding temporary synchronizations between two or more processes to achieve sufficient knowledge. Since synchronizations are expensive, we aim at minimizing their number using the knowledge analysis.