In this paper, we presentRoCC, a robust congestion control approach for datacenter networks based on RDMA.RoCCleverages switch queue size as an input to a PI controller, which computes the fair data rate of flows in the queue. The PI parameters are self-tuning to guarantee stability, rapid convergence, and fair and near-optimal throughput in a wide range of congestion scenarios. Our simulation and DPDK implementation results show thatRoCCcan achieve up to$7\times$reduction in PFC frames generated under high load levels, compared to DCQCN. At the same time,RoCCcan achieve$1.7 - 4.5\times$and$1.4 - 3.9\times$lower tail latency for long flows and$2.1-7\times$and$3.5-8.2\times$lower tail latency for short flows, compared to DCQCN and HPCC, respectively. We also find thatRoCCdoes not require PFC. The functional components ofRoCCcan be efficiently implemented in P4 and FPGA-based switch hardware.

In this paper, we present RoCC, a robust congestion control approach for datacenter networks based on RDMA. RoCC leverages switch queue size as an input to a PI controller, which computes the fair data rate of flows in the queue, signaling it to the flow sources. The PI parameters are self-tuning to guarantee stability, rapid convergence, and fair and near-optimal throughput in a wide range of congestion scenarios. Our simulation and DPDK implementation results show that RoCC can achieve up to 7× reduction in PFC frames generated under high average load levels, compared to DCQCN. At the same time, RoCC can achieve up to 8× lower tail latency, compared to DCQCN and HPCC. We also find that RoCC does not require PFC. The functional components of RoCC are implementable in P4-based and fixed-function switch ASICs.