https://bugs.dpdk.org/show_bug.cgi?id=418
Bug ID: 418 Summary: failsafe/tap PMD drops first UDP packet Product: DPDK Version: 20.02 Hardware: x86 OS: Linux Status: UNCONFIRMED Severity: major Priority: Normal Component: ethdev Assignee: dev@dpdk.org Reporter: step...@networkplumber.org Target Milestone: --- On Azure, the first UDP packet of a flow is being dropped somewhere in the maze of TAP PMD and Failsafe PMD. The packet arrives into the kernel device (netvsc) and is visible with tcpdump but is lost after that. Subsequent UDP packets get redirected to VF and have no problem. This is a TAP/Failsafe PMD problem, and not generic to DPDK. The Netvsc PMD does not have this problem. The suggested fix is to use netvsc PMD instead.. To reproduce: Setup two 8 core VMs, with accelerated networking, running Ubuntu 18. On machine 1 run testpmd in rx only mode. My command line was: # testpmd -l 4,5 -w 0002:00:02.0 --vdev="net_vdev_netvsc0,iface=eth1" -- --forward-mode=rxonly --stats-period=1 On machine 2 run netcat in UDP client mode. $ nc -u 192.168.100.12 1234 Type on machine 2. The first line (packet) is lost and stat does not increment. Second line (packet) does show up. -- You are receiving this mail because: You are the assignee for the bug.