TCP Reassembly Issues

[Kris Bauer]

On Thu, Nov 24, 2011 at 1:20 PM, Raul <raul at turing.b2n.org> wrote:

> El 24/11/2011 17:07, kerbzo escribió:
>
>
>  I 'm experiencing a similar issue but I don't know if mine could be
>> considered normal behaviour: even if net.inet.tcp.reass.curesegments
>> is set to 1680 and does not icrease, the output of vmstat -z shows a
>> high tcpreass fail value that I don't remember in previous (8-STABLE)
>> builds:
>>
>
> I see both, 'net.inet.tcp.reass.cursegments' reaching default
> 'net.inet.tcp.reass.maxsegments' after 38 minutes of uptime, apparently for
> never going down despite the amount of traffic and vmstat -z also show
> tcpreass failures.
>
> I also see sudden packet 'bursts' discarded by memory problems maybe
> related:
> [....]
> %date && netstat -s -p tcp | grep mem
> jueves, 24 de noviembre de 2011, 19:39:23 CET
>                5115 discarded due to memory problems
> %date && netstat -s -p tcp | grep mem
> jueves, 24 de noviembre de 2011, 19:39:30 CET
>                5268 discarded due to memory problems
> [....]
>
> My settings:
> [....]
> %cat /etc/sysctl.conf | grep -v ^\#
> debug.cpufreq.lowest=1000
>
> %cat /boot/loader.conf  | grep -v ^\#
> vfs.zfs.prefetch_disable=0
> aio_load="YES"
> cc_cubic_load="YES"
>
> %sysctl net.isr
> net.isr.numthreads: 1
> net.isr.maxprot: 16
> net.isr.defaultqlimit: 256
> net.isr.maxqlimit: 10240
> net.isr.bindthreads: 0
> net.isr.maxthreads: 1
> net.isr.direct: 0
> net.isr.direct_force: 0
> net.isr.dispatch: direct
> [....]
>
> cc cubic although loaded, not used in this 'pristine' reboot.
> About firewalling, pf using altq.
>
> Pretty recent compile:
> [....]
> %sysctl -a | grep RC2
> kern.osrelease: 9.0-RC2
> kern.version: FreeBSD 9.0-RC2 #0: Thu Nov 24 00:39:07 CET 2011
> [....]
>
> Regards,
> Raúl.
>
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>

I am seeing the same sorts of things in netstat & vmstat:

# netstat -s -p tcp |grep mem
742935 discarded due to memory problems

# vmstat -z |grep tcpreass
tcpreass: 40, 16464, 16340, 124, 131485,955443, 0

I also this filling up of reass.cursegments occur within an hour of reboot.

Thanks,
Kris