As for the DCQCN on RDMA READ flows about ns3-rdma HOT 4 CLOSED

DCQCN relies on the ACK, and can't work for verbs that do not have ACKs. There is ongoing research on this... but I don't know when we can present a production-quality solution.

from ns3-rdma.

Thanks. So, according to your opinion, what is the biggest challenge to provide an additional "fake" ACKs to those operations?

from ns3-rdma.

It's about practical constraints and the trade-off between performance and costs... There are several options

1. Implement an additional ACK mechanism in hardware
2. Implement ACK in software (e.g., hack libibverbs)
3. Avoid using RDMA READ
4. Run RDMA READ without E2E congestion control
5. Implement a feedback mechanism in switches, like QCN, but works for L3 network

You can clearly see each of the options has its price. The real problem is, given the application and setup (and some future applications that you may be able to predict), which is the most cost-effective solution.

from ns3-rdma.

Thanks a lot. The 5 suggestions you gave are very constructive, and i think i need some time to think this thoroughly.

from ns3-rdma.