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Re: [Xen-users] a lot of packet loss

From: Attila Szamos <szamosa@xxxxxxxxx>

Date: Sat, 2 May 2009 02:04:28 +0200

Delivery-date: Fri, 01 May 2009 17:05:19 -0700

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List-id: Xen user discussion <xen-users.lists.xensource.com>

Yes, I do. Ping from perftest6 DomU (perftest7 is not a Xen machine, the OS runs natively on the bare metal): root@perftest-vm2:~# ping perftest7 PING perftest7 (172.27.68.114) 56(84) bytes of data. 64 bytes from perftest7 (172.27.68.114): icmp_seq=1 ttl=64 time=4.00 ms 64 bytes from perftest7 (172.27.68.114): icmp_seq=8 ttl=64 time=0.000 ms 64 bytes from perftest7 (172.27.68.114): icmp_seq=9 ttl=64 time=0.000 ms 64 bytes from perftest7 (172.27.68.114): icmp_seq=10 ttl=64 time=0.000 ms 64 bytes from perftest7 (172.27.68.114): icmp_seq=11 ttl=64 time=0.000 ms 64 bytes from perftest7 (172.27.68.114): icmp_seq=12 ttl=64 time=0.000 ms 64 bytes from perftest7 (172.27.68.114): icmp_seq=13 ttl=64 time=0.000 ms --- perftest7 ping statistics --- 16 packets transmitted, 7 received, 56% packet loss, time 19000ms rtt min/avg/max/mdev = 0.000/0.571/4.000/1.399 ms And I can see this on the perftest6 (dom0): root@perftest6:~# tcpdump -i peth0 > dom0tcp root@perftest6:~# cat dom0tcp | grep ICMP 01:58:08.601810 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 1, length 64 01:58:08.601987 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 1, length 64 01:58:09.597674 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 2, length 64 01:58:10.597695 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 3, length 64 01:58:11.597713 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 4, length 64 01:58:12.597733 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 5, length 64 01:58:13.597752 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 6, length 64 01:58:14.597773 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 7, length 64 01:58:15.597797 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 8, length 64 01:58:15.597957 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 8, length 64 01:58:20.600165 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 9, length 64 01:58:20.600450 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 9, length 64 01:58:21.597909 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 10, length 64 01:58:21.598126 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 10, length 64 01:58:22.597927 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 11, length 64 01:58:22.598174 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 11, length 64 01:58:23.597947 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 12, length 64 01:58:23.598100 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 12, length 64 01:58:24.597967 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 13, length 64 01:58:24.598149 IP perftest7 > perftest-vm2: ICMP echo reply, id 27149, seq 13, length 64 01:58:25.598028 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 14, length 64 01:58:26.598047 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 15, length 64 01:58:27.598066 IP perftest-vm2 > perftest7: ICMP echo request, id 27149, seq 16, length 64 On Sat, May 2, 2009 at 1:50 AM, Fischer, Anna <anna.fischer@xxxxxx> wrote: >> Subject: Re: [Xen-users] a lot of packet loss >> >> I tried another tcpdump-thing. >> >> I pinged from the VM to another non-xen-kernel machine. I ran a >> tcpdump on the xen host machine and the ping-target machine. The point >> is that on the host machine, on which the ICMP packets flow through: >> >> 01:29:53.075672 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 8, length 64 >> 01:29:53.075841 IP perftest7 > perftest-vm2: ICMP echo reply, id >> 24077, seq 8, length 64 >> 01:29:54.075686 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 9, length 64 >> 01:29:54.075884 IP perftest7 > perftest-vm2: ICMP echo reply, id >> 24077, seq 9, length 64 >> 01:29:55.075700 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 10, length 64 >> 01:29:55.075926 IP perftest7 > perftest-vm2: ICMP echo reply, id >> 24077, seq 10, length 64 >> 01:29:56.075715 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 11, length 64 >> 01:29:57.075728 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 12, length 64 >> 01:29:58.075742 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 13, length 64 >> 01:29:59.075761 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 14, length 64 >> 01:30:00.075769 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 15, length 64 >> 01:30:01.075783 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 16, length 64 >> 01:30:02.075798 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 17, length 64 >> 01:30:03.075812 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 18, length 64 >> 01:30:04.075825 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 19, length 64 >> 01:30:05.075840 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 20, length 64 >> 01:30:05.075987 IP perftest7 > perftest-vm2: ICMP echo reply, id >> 24077, seq 20, length 64 >> 01:30:10.082287 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 21, length 64 >> 01:30:10.082448 IP perftest7 > perftest-vm2: ICMP echo reply, id >> 24077, seq 21, length 64 >> 01:30:11.079923 IP perftest-vm2 > perftest7: ICMP echo request, id >> 24077, seq 22, length 64 >> >> On the perftest7 machine if a packet arrives, it gets a reply. So it >> seems that the packets are lost on the network. It imples that the >> problem is with the network, but If I dont use domU-s, there is no >> unreplied packets. > > Well it depends. It could be that those lost packets actually never leave > Dom0. Do you see them going out on the physical interface (e.g. peth0 or > something like that) on Dom0 ? > _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users

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