Slow local TCP transfers on -CURRENT

[Lawrence Stewart]

George Neville-Neil wrote:
> 
> On May 2, 2009, at 08:16 , Lawrence Stewart wrote:
> 
>> Kevin Day wrote:
>>> I've been seeing this for a few months now on -CURRENT. TCP transfers 
>>> to local IP addresses (but not 127.0.0.1) are incredibly slow.
>>> Transfer from localhost:
>>> # scp "root at 127.0.0.1:/boot/kernel/kernel" .
>>> kernel                                                                          
>>> 100%   11MB  11.1MB/s   00:00
>>> Appropriately fast.
>>> Transfer from an IP on a local interface:
>>> # scp "root at 216.14.96.4:/boot/kernel/kernel" .
>>> kernel                                                                            
>>> 0%   16KB  13.0KB/s   14:37 ETA
>>> The routes seem normal:
>>> # route get 127.0.0.1
>>>  route to: localhost
>>> destination: localhost
>>> interface: lo0
>>>     flags: <UP,HOST,DONE,LOCAL>
>>> recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire
>>>      0         0         0         0     16384         1         0
>>> # route -n get 216.14.96.4
>>>  route to: 216.14.96.4
>>> destination: 216.14.96.0
>>>      mask: 255.255.255.128
>>> interface: nfe0
>>>     flags: <UP,DONE>
>>> recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire
>>>      0         0         0         0      1500         1         0
>>> nfe0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 
>>> 1500
>>>       
>>> options=19b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4>
>>>       ether 00:30:48:c6:dd:9c
>>>       inet 216.14.96.4 netmask 0xffffff80 broadcast 216.14.96.127
>>> Takes 10-60 minutes to copy, stalling frequently during the transfer. 
>>> It's not limited to just scp either, all TCP transfers seem to stall 
>>> this way.
>>> I don't believe I'm doing anything unusual, has anyone seen anything 
>>> like this?
>>
>> Known fallout from the ARPv2 work I believe. As a workaround until it 
>> gets fixed:
>>
>> route add -host (if-ip) -iface lo0 (note I haven't tested this myself)
>>
>> (see the Jan 2009 freebsd-net@ thread "Bacula: VERY SLOW on SAME host" 
>> for some details).
>>
> 
> Anyone know if there is a fix in the offing?

Qing (added to CC) is aware of the problem. Not sure how far off the fix is.

Cheers,
Lawrence