TCP packet out-of-order problem

[Robert Watson]

On Tue, 6 Jan 2009, Lin Jui-Nan Eric wrote:

> I thought that the system auto-tune improperly in this case.

Hmm.  Do you have a custom setting for kern.ipc.nmbclusters in loader.conf or 
sysctl.conf?  What does kern.ipc.nmbclusters configure itself to on your 
system?  Also, could you send me the output of uname -a on the system?

Thanks,

Robert N M Watson
Computer Laboratory
University of Cambridge

> On Mon, Jan 5, 2009 at 9:13 PM, Robert Watson <rwatson at freebsd.org> wrote:
>> On Fri, 2 Jan 2009, Lin Jui-Nan Eric wrote:
>>
>>> After running "netstat -s -p tcp", we found that lots of packets are
>>> discarded due to memory problems. We googled for it, and found that sysctl
>>> oid "net.inet.tcp.reass.maxsegments" became 0, therefore packets never
>>> reassembled.
>>>
>>> Then we checked our /boot/loader.conf and /etc/sysctl.conf, and found that
>>> setting kern.ipc.nmbclusters="0" makes net.inet.tcp.reass.maxsegments=0.
>>> After setting net.inet.tcp.reass.maxsegments="1600" in /boot/loader.conf,
>>> the network works perfectly now.
>>
>> Was it set to 0 through a configuration error, or did the system auto-tune
>> improperly?
>>
>> Robert N M Watson
>> Computer Laboratory
>> University of Cambridge
>>
>>>
>>> Thank you all for the help!
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>>
>