Abstract: Network congestion has become one of the main problems in bufferless No C, which not only degrades system throughput but also limits network scalability. Prior works only throttle the applications with high network intensity, incapable of controlling network congestion accurately. In this paper, we propose a DAT congestion control mechanism for bufferless No C, which determines the throttle sources quickly using distributed deflection monitor tables to record the deflections of network packets. And DAT takes network utilization into account when adjusting the throttling rate. Our evaluations show that DAT can reduce the deflection rate by 8.6% on average in a simulated 16 core system compared to baseline bufferless No C with good scalability and low hardware cost.