pipe dropping lots of packets

[Alex Povolotsky]

Hello!

I'm trying to set up FreeBSD-based router, and got troubles with 
bandwidth limiting. My queues drops lots of packets.

[23:38] gw:~ # ipfw pipe 200 config bw 30mbit/s queue 100
[23:42] gw:~ # ipfw add 600 pipe 200 ip from any to any out via vlan333
00600 pipe 200 ip from any to any out via vlan333

seems to be easy. now

[23:43] gw:~ # ipfw zero
Accounting cleared.

make sure we'll catch packets out of pipe

[23:43] gw:~ # sysctl net.inet.ip.fw.one_pass
net.inet.ip.fw.one_pass: 0

and, waiting a bit

[23:43] gw:~ # ipfw show | grep vlan333
00600   2010    140730 pipe 200 ip from any to any out via vlan333
00700      0         0 allow ip from any to table(1) via vlan333
00710    840    142335 allow ip from table(1) to any via vlan333

whoops! No packets left pipe

part of ipfw pipe list

00200:  30.000 bit/s     0 ms  100 sl. 1 queues (1 buckets) droptail
    mask: 0x00 0x00000000/0x0000 -> 0x00000000/0x0000
BKT Prot ___Source IP/port____ ____Dest. IP/port____ Tot_pkt/bytes 
Pkt/Byte Drp
  0 tcp   172.23.114.136/6220    217.70.17.154/3931  7292   683466 100 
12092 7048

As far as I understand, pipe dropped most of tcp packets, didn't it?

Of course, people complaints of network "not working".

Eventually, some packets gets out of queue, but with 30 mbit/s pipe on 
100 mbit link I'd expect to drop 2/3 packets at most, not 99 of 100

00600   1012     64217 pipe 200 ip from any to any out via vlan333
00700     14       560 allow ip from any to any out via vlan333

What could I do wrong? System is fairly unloaded. External card is Intel 
PRO 100/1000;

last pid: 11209;  load averages:  0.52,  0.36,  
0.34                                            up 5+19:37:14  23:52:17
70 processes:  2 running, 68 sleeping
CPU states:  1.3% user,  0.0% nice,  6.4% system, 14.1% interrupt, 78.2% 
idle
Mem: 87M Active, 673M Inact, 195M Wired, 33M Cache, 111M Buf, 8324K Free
Swap: 4096M Total, 4096M Free

top shows quite little load on system.

Alex.
(FreeBSD 6.1-RELEASE)