if_bridge drops lot of outgoing packets

[Artis Caune]

# kldload if_bridge
# ifconfig bridge0 create
# ifconfig bridge0 addm em0
# ifconfig bridge0 -learn em0
# ifconfig bridge0 span em1
# ifconfig bridge0 up

traffic on em0:
   30 second output rate 680818000 bits/sec, 152697 packets/sec

# netstat -w1 -bd -I em1
             input        (em1)           output
    packets  errs       bits    packets  errs       bits colls drops
          0     0          0     107332     0  493295560     0 50374
          0     0          0     105825     0  484738088     0 53434
          0     0          0     109800     0  499006384     0 44857
          0     0          0     110054     0  493731344     0 46474
          0     0          0     106508     0  486585112     0 54058
          0     0          0     105180     0  484695272     0 52910
          0     0          0     105304     0  485654248     0 54242

~ 51% packet loss per second



FreeBSD 7.0-CURRENT #0: Fri Feb 24 12:57:50 EET 2006
device   = '82546EB Dual Port Gigabit Ethernet Controller' (pcix)
VM_KMEM_SIZE_MAX=536870912 (512M)
kern.ipc.nmbclusters=100000
dual 2.8GHz xeon
2G RAM
POLLING not compiled in

changes in if_em.h:
    #define EM_DEFAULT_TXD          EM_MAX_TXD //(4096)
    #define EM_DEFAULT_RXD          EM_MAX_RXD //(4096)
    #define EM_TIDV                         0
    #define EM_TADV                         0
    #define EM_RADV                         0


same problem with unmodified if_em/KMEM/clusters