On Mon, Jul 21, 2025 at 3:25 PM Larysa Zaremba <[email protected]> wrote: > > On Sat, Jul 19, 2025 at 01:26:18PM +0800, Jason Xing wrote: > > On Fri, Jul 18, 2025 at 6:27 PM Larysa Zaremba <[email protected]> > > wrote: > > > > > > On Wed, Jul 16, 2025 at 11:41:42AM +0800, Jason Xing wrote: > > > > Hi all, > > > > > > > > I'm currently faced with one tough issue caused by zero copy mode in > > > > xsk with ixgbe driver loaded. The case is that if we use xdpsock to > > > > send descs, nearly at the same time normal packets from other tx > > > > queues cannot be transmitted/completed at all. > > > > > > > > Here is how I try: > > > > 1. run iperf or ping to see if the transmission is successful. > > > > 2. then run "timeout 5 ./xdpsock -i enp2s0f0 -t -z -s 64" > > > > > > > > You will obviously find the whole machine loses connection. It can > > > > only recover as soon as the xdpsock is stopped due to timeout. > > > > > > > > I tried a lot and then traced down to this line in ixgbe driver: > > > > ixgbe_clean_tx_irq() > > > > -> if (!(eop_desc->wb.status & cpu_to_le32(IXGBE_TXD_STAT_DD))) > > > > break; > > > > The above line always 'breaks' the sending process. > > > > > > > > I also managed to make the external ixgbe 6.15 work and it turned out > > > > to be the same issue as before. > > > > > > > > I have no idea on how to analyze further in this driver. Could someone > > > > point out a direction that I can take? Is it a known issue? > > > > > > > > Thanks, > > > > Jason > > > > > > > > > > I was able to reproduce the described behaviour, xdpsock does break the IP > > > communication. However, in my case this was not because of ixgbe not > > > being able > > > to send, but because of queue 0 RX packets being dropped, which is the > > > indended > > > outcome in xdpsock, even in Tx only mode. > > > > Thanks for your feedback. It would be great if you could elaborate > > more on this. How did you spot that it's queue 0 that causes the > > problem? > > If you do not specify -q parameter, xdpsock loads on the queue pair 0. > > > Why is xdpsock breaking IP communication intended? > > Because when a packet arrives on the AF_XDP-managed queue (0 in this case), > the > default xdpsock XDP program provided by libxdp returns XDP_REDIRECT even in > tx-only mode, XDP_PASS for all other queues (1-39). XDP_REDIRECT results in a > packet leaving the kernel network stack, it is now managed by the AF_XDP > userspace program. I think it is possible to modify libxdp to return XDP_PASS > when the socket is tx-only. > > > > > When you try i40e, you will find the connection behaves normally. Ping > > can work as usual. As I depicted before, with ixgbe driver, ping even > > doesn't work at all. > > I think this is due to RSS configuration, ping packets on i40e go to another > queue.
Thanks so much for your detailed explanation. But, I still doubt it's not the reason why xdpsock breaks with ixgbe driver loaded because I tried the following commands: 1. ping <ip> 2. timeout 3 ./xdpsock -i enp2s0f0np0 -t -q 11 -z -s 64 Whatever the queue value I adjusted, ping always fails with "Destination Host Unreachable" warning. Thanks, Jason
