Slow local TCP transfers on -CURRENT

[George Neville-Neil]

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?

Best,
George