TCP packet out-of-order problem

[Lin Jui-Nan Eric]

Oops, we surely have kern.ipc.nmbclusters="0" in loader.conf, but I
think that should not modify net.inet.tcp.reass.maxsegments to "0"
since we wish unlimited nmbclusters but not zero TCP reassembly
segments.

On Tue, Jan 6, 2009 at 4:16 PM, Robert Watson <rwatson at freebsd.org> wrote:
>
> 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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>>>
>>
>