On Thu, Jun 13, 2019 at 06:58:30PM +0200, Håkon Bugge wrote: > If you refer to the backlog parameter in rdma_listen(), I cannot see > it being used at all for IB. > > For CX-3, which is paravirtualized wrt. MAD packets, it is the proxy > UD receive queue length for the PF driver that can be construed as a > backlog. No, in IB you can drop UD packets if your RQ is full - so the proxy RQ is really part of the overall RQ on QP1. The backlog starts once packets are taken off the RQ and begin the connection accept processing. > Customer configures #VMs and different workload may lead to way > different number of CM connections. The proxying of MAD packet > through the PF driver has a finite packet rate. With 64 VMs, 10.000 > QPs on each, all going down due to a switch failing or similar, you > have 640.000 DREQs to be sent, and with the finite packet rate of MA > packets through the PF, this takes more than the current CM > timeout. And then you re-transmit and increase the burden of the PF > proxying. I feel like the performance of all this proxying is too low to support such a large work load :( Can it be improved? Jason
