Messages in this thread | | | Date | Mon, 26 May 2008 15:59:40 +0200 | From | Ingo Molnar <> | Subject | Re: [bug] stuck localhost TCP connections, v2.6.26-rc3+ |
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* Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> wrote:
> > in terms of debugging there's not much i can do i'm afraid. It's not > > possible to get a tcpdump of this incident, given the extreme amount > > of load these testboxes handle. > > ...but you can still tcpdump that particular flow once the situation > is discovered to see if TCP still tries to do something, no? One needs > to tcpdump couple of minutes at minimum. Also please get /proc/net/tcp > for that flow around the same time.
ok, will try those.
> > One clue (which might or might not matter) is that distcc is one of > > the very few applications that makes use of sendfile(). > > Can you please try with /proc/sys/net/ipv4/tcp_frto set to zero though > recv-q symptom seems weird would it be related to that (but there were > some recent fixes to FRTO and retrans_stamp change could have some > significance here)? > > Other than that, nothing since -rc1 seems suspicious to me (though I > hardly understand every part of networking).
ok, i will first wait for it to trigger on a box and will do the tcpdump session (and /proc/net/tcp output), then i'll continue the tests with this done in the rc.local:
echo 0 > /proc/sys/net/ipv4/tcp_frto
and will see whether the hung connections still occur. The cycle of testing will be very slow i suspect.
Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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