Hi Magnus, >> I am the maintainer of the AF_XDP driver for VPP, an open-source >> userspace networking stack, and I ran into an issue recently with kernels >> < 5.6 (including LTS kernel 5.4 which is shipped in eg. Ubuntu 20.04 LTS): >> it seems like one cannot call poll() and sendmsg() concurrently on the >> same AF_XDP socket. Is this a supported usecase? [...] >> I hit a 2nd issue with kernel >= 5.9, where the headroom on rx for copy >> mode has grown from 0 to XDP_PACKET_HEADROOM (256-bytes). [...] > Hi Benoit. Thank you for reporting, I will take a look at this and get > back to you. Next time, please add me and Björn on the to line so that > you get a quicker response. Thanks! Sure I will in the future. If I may, an ideal scenario would be: 1) the concurrent rx/tx usecase is officially supported, and 11cc2d21499cabe7e7964389634ed1de3ee91d33 should be backported to LTS 2) had a way to detect different version of AF_XDP (through an ioctl() or getsockopt() or...) so that I can detect more easily what I should do at init time. Eg. managing both headroom (0 and 256) for copy mode is not very difficult if I can detect it easily Best ben
