TCP problems after 124 days of uptime?

[Julian Elischer]

Andre Oppermann wrote:
> Gleb Smirnoff wrote:
>>   Yesterday two of our web servers running 6.2-PRERELEASE experienced
>> problems with accepting TCP connections. A small percentage of SYN
>> packets was ignored. The packets were seen in tcpdump output, but not
>> processed by TCP stack. No accept queue overflows occured, according
>> to 'netstat -sp tcp'.
>>
>> Failing to find any clue I have rebooted one of them, and after
>> reboot is started to work flawlessly. Reboot also helped the second
>> one. Both servers were booted at the same time - 124 days ago.
>>
>> Any ideas, any similar reports?
> 
> ticks is a 32 bit signed integer and TCP isn't really aware of it
> going negative and rolling over.  This is something I'm working on
> fixing in -current.  Haven't analyzed all potential cases there yet.
> 

124 days is 32 bits at 400Hz
or 30 bits at 100Hz

what is the granularity of the TCP timer?