I'm occasionally seeing a slow xennet is domU:
Throughput is perhaps 20% of normal, and pings are about 5 times
higher.
When the problem occurs, it's always present from boot.
When the first xennet is slow at boot time, I can add a second xennet
and it will usually be fast.
Usually one reboot will fix the problem.
I've seen this on NetBSD 6 and 7.
I'm seeing this pretty consistently on NetBSD 7, NetBSD 5 is fine. dom0 is
XenServer, domUs are on same host. Rebooting makes no difference. This is
IMHO a serious problem.
NetBSD-5 domU -> physical host:
NETIO - Network Throughput Benchmark, Version 1.26
(C) 1997-2005 Kai Uwe Rommel
TCP connection established.
Packet size 1k bytes: 103375 KByte/s Tx, 81319 KByte/s Rx.
Packet size 2k bytes: 107507 KByte/s Tx, 96727 KByte/s Rx.
Packet size 4k bytes: 110407 KByte/s Tx, 94854 KByte/s Rx.
Packet size 8k bytes: 111326 KByte/s Tx, 108494 KByte/s Rx.
Packet size 16k bytes: 111244 KByte/s Tx, 107681 KByte/s Rx.
Packet size 32k bytes: 111291 KByte/s Tx, 99243 KByte/s Rx.
Done.
NetBSD-7 domU -> physical host:
NETIO - Network Throughput Benchmark, Version 1.26
(C) 1997-2005 Kai Uwe Rommel
TCP connection established.
Packet size 1k bytes: 9641 KByte/s Tx, 9890 KByte/s Rx.
Packet size 2k bytes: 11940 KByte/s Tx, 11718 KByte/s Rx.
Packet size 4k bytes: 11529 KByte/s Tx, 12110 KByte/s Rx.
Packet size 8k bytes: 11485 KByte/s Tx, 12266 KByte/s Rx.
Packet size 16k bytes: 11435 KByte/s Tx, 12051 KByte/s Rx.
Packet size 32k bytes: 11501 KByte/s Tx, 12287 KByte/s Rx.
Done.