Messages in this thread | | | Date | Wed, 23 Jul 2008 10:26:43 +0200 | From | Ingo Molnar <> | Subject | Re: [TCP bug] stuck distcc connections in latest -git |
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* Willy Tarreau <w@1wt.eu> wrote:
> On Tue, Jul 22, 2008 at 05:34:43PM +0200, Ingo Molnar wrote: > > * David Newall <davidn@davidnewall.com> wrote: > > > > > Ingo Molnar wrote: > > > > * David Newall <davidn@davidnewall.com> wrote: > > > > > > > >> 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. > > > > > > You only need distcc traffic, and perhaps only after it's hung. With > > > 250k outstanding per socket, are you certain that no traffic was sent? > > > Is it certain that one packet wasn't being sent each three minutes? I > > > suppose you're right and the stack really is stuck, but this is such > > > an easy thing to check and eliminate that you should do so. I > > > suppose, too, that you should trace the server-side processes and > > > confirm that they are waiting for socket input. You should dump tcp > > > (for the distcc port) next time the problem recurs and also check that > > > the server processes are waiting for socket input. > > > > ok, will do that if it happens again. > > Ingo, > > if it can help, I have a "capture" script which allows you to define a > size and will rotate captures within that size. That's what I'm using > to troubleshoot rarely occuring problems in datacenters, so it's > horrible but efficient :-) > > You just have to stop it once the problem has happened again. Ping me > if you're interested (I'm lazy to start my laptop right just for it > now in fact).
yeah, that would be handy, thanks.
Alas, the problem has not reoccured since then - more than a thousand kernel builds down the line. Yesterday it triggered so quickly when i updated the buildbox to the new kernel, and happened repeatedly when i tried to build a new kernel, that i didnt assume it was something hard to reproduce - but it went poof after i restarted distccd on the server.
So i'd suggest we do not count this as a regression, i've got no way at the moment of reproducing it reliably.
Ingo
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