On 04/15/2018 06:47 PM, Dominique Martinet wrote:
> Also, here are the per-socket stats I could find (ss -i after having > reproduced hang): > reno wscale:7,7 rto:7456 backoff:5 rtt:32.924/1.41 ato:40 mss:1374 > pmtu:1500 rcvmss:1248 advmss:1448 cwnd:1 ssthresh:16 > bytes_acked:32004 bytes_received:4189 segs_out:85 segs_in:54 > data_segs_out:78 data_segs_in:18 send 333.9Kbps lastsnd:3912 > lastrcv:11464 lastack:11387 pacing_rate 21.4Mbps delivery_rate > 3.5Mbps busy:12188ms unacked:33 retrans:1/5 lost:33 rcv_rtt:37 > rcv_space:29200 rcv_ssthresh:39184 notsent:28796 minrtt:24.986 > ss -temoi might give us more info Really it looks like at some point, all incoming packets are shown by tcpdump but do not reach the TCP socket anymore. (segs_in: might be steady, look at the d0 counter shown by ss -temoi (dX : drop counters, sk->sk_drops) Are you sure you do not have some iptables/netfilter stuff ? While running your experiment, try on the server. perf record -a -g -e skb:kfree_skb sleep 30 perf report
