From: Paolo Abeni <pabeni@redhat•com>
To: Marc Haber <mh+netdev@zugschlus•de>
Cc: netdev@vger•kernel.org
Subject: Re: After a while of system running no incoming UDP any more?
Date: Tue, 25 Jul 2017 14:17:52 +0200 [thread overview]
Message-ID: <1500985072.13149.4.camel@redhat.com> (raw)
In-Reply-To: <20170725115745.bbguoecrcsfhbm7f@torres.zugschlus.de>
On Tue, 2017-07-25 at 13:57 +0200, Marc Haber wrote:
> On Mon, Jul 24, 2017 at 04:19:10PM +0200, Paolo Abeni wrote:
> > Once that a system enter the buggy status, do the packets reach the
> > relevant socket's queue?
> >
> > ss -u
>
> That one only shows table headers on an unaffected system in normal
> operation, right?
This one shows the current lenght of the socket receive queue (Recv-Q,
the first column). If the packets land into the skbuff (and the user
space reader for some reason is not woken up) such value will grow over
time.
> > nstat |grep -e Udp -e Ip
> >
> > will help checking that.
>
> An unaffected system will show UdpInDatagrams, right?
>
> But where is the connection to the relevant socket's queue?
If the socket queue lenght (as reported above) does not increase,
IP/UDP stats could give an hint of where and why the packets stop
traversing the network stack.
Beyond that, you can try using perf probes or kprobe/systemtap to [try
to] track the relevant packets inside the kernel.
/P
next prev parent reply other threads:[~2017-07-25 12:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-24 12:09 After a while of system running no incoming UDP any more? Marc Haber
2017-07-24 14:19 ` Paolo Abeni
2017-07-25 11:57 ` Marc Haber
2017-07-25 12:17 ` Paolo Abeni [this message]
2017-07-26 8:10 ` Marc Haber
2017-07-26 8:33 ` Paolo Abeni
2017-07-28 6:26 ` Marc Haber
2017-07-28 8:05 ` Eric Dumazet
2017-07-28 8:15 ` Paolo Abeni
2017-07-28 8:41 ` Eric Dumazet
2017-07-28 8:07 ` Paolo Abeni
2017-07-28 12:14 ` Marc Haber
2017-08-11 14:34 ` Marc Haber
2017-08-11 20:07 ` Marc Haber
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