Re: High packet loss in netbsd-5.0 domU

[Anup Patil <anupp%gmx.net@localhost>]

On Tue, 2009-04-21 at 21:59 +0200, Manuel Bouyer wrote:
> On Tue, Apr 21, 2009 at 04:24:40PM +0200, Anup Patil wrote:
> > 
> > On a netbsd-5.0 RC2 domU under xen-3.3.1, It was found that packet
> > losses were upto 50% for udp network tests. The network load was
> > generated using iperf and udp datagrams of length 100 to 1470 were
> > transmitted.
> 
> What network test ? who is sending the datagram and who is receiving them ?
> Did you check that the dom0 can handle the network load ? What OS is
> the dom0 running ?
> 

Dom0 is linux-2.6.18.8, built from the xen sources. 
The sender and receiver is iperf
( http://sourceforge.net/projects/iperf/)

Receiver is  connected to the dom0 by a 100 Mb/s switch, and cpu load in
dom0 seems to be all right as other domU's (linux 2.18.8 ) perform
differently.

Sending datagrams of length 1000bytes, from netbsd domU (5.0_RC2 NetBSD
5.0_RC2) The following was seen.

root@nbsdpvm:[~/build/iperf-2.0.4/src]> ./iperf  -u -c 10.10.19.201  -l
1000 -b 70M -w 100K
------------------------------------------------------------
Client connecting to 10.10.19.201, UDP port 5001
Sending 1000 byte datagrams
UDP buffer size:   100 KByte
------------------------------------------------------------
[  3] local 10.10.19.17 port 65421 connected with 10.10.19.201 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  21.6 MBytes  18.1 Mbits/sec
[  3] Sent 22660 datagrams
[  3] Server Report:
[ ID] Interval       Transfer     Bandwidth       Jitter   Lost/Total
Datagrams
[  3]  0.0-10.0 sec  16.8 MBytes  14.0 Mbits/sec  2.595 ms 5061/22659
(22%)
[  3]  0.0-10.0 sec  1 datagrams received out-of-order


So 22659 datagrams of length 1000 are send and 5061 datagrams are lost.


Anup Patil