Date: Thu, 24 May 2007 23:44:23 +0200 From: Andre Oppermann <andre@freebsd.org> To: Julian Elischer <julian@elischer.org> Cc: Gleb Smirnoff <glebius@FreeBSD.org>, net@FreeBSD.org Subject: Re: TCP problems after 124 days of uptime? Message-ID: <46560737.8090203@freebsd.org> In-Reply-To: <46560407.9080404@elischer.org> References: <20070524182545.GF89017@FreeBSD.org> <4655EEAD.2060307@freebsd.org> <46560407.9080404@elischer.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Julian Elischer wrote: > 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? ticks == HZ This isn't necessarily a TCP timer issue. It may just as well come from timestamps or RTT calculation that is done based on ticks derived values. -- Andre
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?46560737.8090203>