Networking: Lots of collisions?

[Fredrik Pettai <pettai%nordu.net@localhost>]

Hi, 
I just installed a netbsd-5-1-RC4 as a dns server, and I see a lot of 
collisions:

 pcn0 in       pcn0 out              total in      total out            
 packets  errs  packets  errs colls   packets  errs  packets  errs colls
39428897     0 22000706     0 5500180  39428897     0 22001100     0 5500180
    3227     0     1892     0   474      3227     0     1892     0   474
    3373     0     2060     0   514      3373     0     2060     0   514
    3168     0     1926     0   482      3168     0     1926     0   482

Now, since it's running in VMware, one could guess that it's a underlying 
problem (in VMware or maybe even in the physical infrastructure).
But I also have virtualized Linux machines that are quite busy too, and they 
don't show this kind of networking problem.
(They run in the same VMware hardware)

Trying to do a tcpdump shows that the netbsd system doesn't handle that very 
well either:

# tcpdump -i pcn0
[...]
^C
5 packets captured
2585 packets received by filter
1726 packets dropped by kernel 

Doing it on the Linux machine works fine:

# tcpdump -i eth0
[...]
^C
2844 packets captured
2845 packets received by filter
0 packets dropped by kernel

To that I might add that the servers doesn't have any typical CPU load etc.

# top -o cpu 
load averages:  0.59,  0.65,  0.65;               up 0+12:32:18        23:05:05
24 processes: 23 sleeping, 1 on CPU
CPU states:  0.0% user,  0.0% nice,  2.0% system,  2.0% interrupt, 96.0% idle
Memory: 306M Act, 2852K Inact, 6040K Wired, 7980K Exec, 117M File, 155M Free
Swap: 256M Total, 256M Free
  PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
 3929 user    85    0    94M   91M netio     20:49  2.69%  2.69% [dns process]

Anybody else that has seen something similar? (in VMware?)
Any hints on what to do to make the networking stack more optimized? It's 
currently just the defaults.

/P