Hi Ben, > > (I think there may be a problem with the rdma plugin for larger MTU > > values but for MTU < 2000 or so, everything works fine.) > > It should work, jumbo support was added in the last months. Or do you > refer to something else?
I think I mean something else, a problem that I noticed a few weeks ago but never had time to report it then. Now I tried again and it can still be reproduced with the current master branch. The setup is that I have one server running VPP doing NAT44 and then I have two other servers on inside and outside. This works fine when the MTU is 1500. Then I set the MTU to 3000 on all involved interfaces and restart VPP. Now it works as longas only small packets are used, but as soon as a packet larger than ~2048 bytes appears, VPP stops working. (Doing e.g. ping -s 2100 is enough to trigger it.) After that VPP is stuck in some kind of error state from which it does not recover, even small packets are not forwarded after that. I tried to investigate further and then it seemed like that what happens is that the RDMA_DEVICE_F_ERROR flag is set in src/plugins/rdma/input.c which causes the rdma plugin code to get stuck, the error flag is never cleared it seems. The reason why the larger packet size caused an error seems to be that the log2_cq_size value used in src/plugins/rdma/input.c is log2_cq_size = 11 which corresponds to 2^11 = 2048 bytes which is roughly the packet size where the problem appears. So I got the impression that the rdma plugin is limited to 2^11 = 2048 bytes MTU due to the log2_cq_size = 11 value. Maybe that can be configured somehow? In any case, it seems bad that VPP gets stuck after one such error appears, it would be better if it just increased an error counter and dropped the packet. Best regards, Elias
-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#16612): https://lists.fd.io/g/vpp-dev/message/16612 Mute This Topic: https://lists.fd.io/mt/74623336/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
