breaking news : output from iperf shows we are losing packets on udp as well for a bandwidth setting above 4m. ./iperf -s -u -i 1 ------------------------------------------------------------ Server listening on UDP port 5001 Receiving 1470 byte datagrams UDP buffer size: 105 KByte (default) ------------------------------------------------------------ [ 3] local 192.168.60.11 port 5001 connected with 192.168.60.13 port 1026 [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 3] 0.0- 1.0 sec 1.02 MBytes 8.54 Mbits/sec 0.361 ms 0/ 726 (0%) [ 3] 1.0- 2.0 sec 1.28 MBytes 10.7 Mbits/sec 0.048 ms 67/ 978 (6.9%) [ 3] 2.0- 3.0 sec 1.19 MBytes 10.0 Mbits/sec 0.043 ms 0/ 850 (0%) [ 3] 3.0- 4.0 sec 1.19 MBytes 10.0 Mbits/sec 0.068 ms 0/ 851 (0%) [ 3] 4.0- 5.0 sec 1.03 MBytes 8.63 Mbits/sec 0.037 ms 115/ 849 (14%) [ 3] 5.0- 6.0 sec 1.19 MBytes 10.0 Mbits/sec 0.040 ms 0/ 851 (0%) [ 3] 6.0- 7.0 sec 1.19 MBytes 10.0 Mbits/sec 0.060 ms 0/ 850 (0%) [ 3] 7.0- 8.0 sec 1002 KBytes 8.21 Mbits/sec 0.244 ms 0/ 698 (0%) [ 3] 8.0- 9.0 sec 1.19 MBytes 10.0 Mbits/sec 0.419 ms 0/ 850 (0%) [ 3] 9.0-10.0 sec 1.19 MBytes 9.98 Mbits/sec 0.064 ms 0/ 849 (0%) [ 3] 0.0-10.0 sec 11.5 MBytes 9.61 Mbits/sec 0.062 ms 182/ 8353 (2.2%) ./iperf -c p0e0 -u -b 10m ------------------------------------------------------------ Client connecting to p0e0, UDP port 5001 Sending 1470 byte datagrams UDP buffer size: 105 KByte (default) ------------------------------------------------------------ [ 5] local 192.168.60.13 port 1026 connected with 192.168.60.11 port 5001 [ ID] Interval Transfer Bandwidth [ 5] 0.0-10.0 sec 11.7 MBytes 9.81 Mbits/sec [ 5] Server Report: [ 5] 0.0-10.0 sec 11.4 MBytes 9.59 Mbits/sec 0.539 ms 187/ 8344 (2.2%) [ 5] Sent 8344 datagrams Thus we see packet loss. However when we set the client bandwith (-b 4m) all is fine, but anything above this causes packet loss. I expect there to be very little loss (<1%) under these conditions. The two nodes above are in the same physical box, on separate processors, each running their own kernel separated by a switch that only has traffic between the nodes. output when tcpdump is run as well wtih no cmd line options /flash/sbin # ./iperf -s -u -i 1 ------------------------------------------------------------ Server listening on UDP port 5001 Receiving 1470 byte datagrams UDP buffer size: 105 KByte (default) ------------------------------------------------------------ [ 3] local 192.168.60.11 port 5001 connected with 192.168.60.13 port 1026 [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 3] 0.0- 1.0 sec 482 KBytes 3.95 Mbits/sec 0.321 ms 0/ 336 (0%) [ 3] 1.0- 2.0 sec 485 KBytes 3.97 Mbits/sec 0.050 ms 7/ 345 (2%) [ 3] 2.0- 3.0 sec 490 KBytes 4.01 Mbits/sec 0.054 ms 0/ 341 (0%) [ 3] 3.0- 4.0 sec 488 KBytes 4.00 Mbits/sec 0.077 ms 0/ 340 (0%) [ 3] 4.0- 5.0 sec 422 KBytes 3.46 Mbits/sec 0.154 ms 0/ 294 (0%) [ 3] 5.0- 6.0 sec 488 KBytes 4.00 Mbits/sec 0.051 ms 0/ 340 (0%) [ 3] 6.0- 7.0 sec 488 KBytes 4.00 Mbits/sec 0.122 ms 0/ 340 (0%) [ 3] 7.0- 8.0 sec 425 KBytes 3.48 Mbits/sec 0.154 ms 0/ 296 (0%) [ 3] 8.0- 9.0 sec 551 KBytes 4.52 Mbits/sec 0.304 ms 0/ 384 (0%) [ 3] 9.0-10.0 sec 488 KBytes 4.00 Mbits/sec 0.058 ms 0/ 340 (0%) [ 3] 0.0-10.0 sec 4.70 MBytes 3.94 Mbits/sec 0.059 ms 7/ 3357 (0.21%) Packet loss is lower?? - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
