Messages in this thread | | | Date | Tue, 22 Jul 2008 15:57:23 +0200 | From | Ingo Molnar <> | Subject | Re: [TCP bug] stuck distcc connections in latest -git |
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* David Newall <davidn@davidnewall.com> wrote:
> > The hung condition seemed permanent (i waited a couple of minutes). > > Not nearly long enough. Retransmits can be sent as infrequently as > per 180 seconds. I think there's an argument to use one of the the > various patches that reduce your TCP_RTO_MAX, for example OBATA > Noboru's (http://marc.info/?l=linux-netdev&m=118422471428855): you > don't have to wait unreasonably long before seeing a retransmit. > Remember, three minutes!
i know, i waited much more than 180 minutes - about 15 minutes. That is more than enough for this LAN connection.
It's all on the LAN directly via a single gigabit switch and no packet dropping. I noticed the hung build immediately as it happened.
> > I retried the same build 10 times and it would not reproduce - so > > this again is a hard to reproduce condition. (and there's no chance > > to get a proper tcpdump either, at these traffic levels) > > You really should start that capture, and on both client and server. > You don't need to dump everything, only traffic to or from > server:distcc.
It's not feasible. That box did in excess of 200 GB of network traffic in the past 7 hours alone. ~10 clients are doing make -j200 type of kernel builds to this 16way buildbox so it is not realistic to tcpdump it - especially given the rarity of this problem. (it has not reoccured since then) The network is local LAN, gigabit ethernet over a single gigabit switch.
Ingo
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