Long io loop / missing netlink messages

Maria Matějka maria.matejka at nic.cz
Sun Dec 22 16:10:12 CET 2019


Hello!

How much time does it take to list the kernel table?

time ip r > /dev/null

How many routes do you have in bird table?

show route count

And what export filter do you have for the kernel protocol in bird?

Thanks
Maria

On December 21, 2019 1:07:25 PM GMT+01:00, Nico Schottelius <nico.schottelius at ungleich.ch> wrote:
>
>Good morning,
>
>on a fresh new router running the full routing table,
>with Alpine, Linux 4.19.80-0-vanilla, bird-2.0.7
>
>I see a lot of these messages:
>
>Dec 21 12:37:15 router1 daemon.warn bird: Kernel dropped some netlink
>messages, will resync on next scan.
>Dec 21 12:37:34 router1 daemon.warn bird: I/O loop cycle took 5000 ms
>for 1 events
>Dec 21 12:38:14 router1 daemon.warn bird: Kernel dropped some netlink
>messages, will resync on next scan.
>Dec 21 12:38:35 router1 daemon.warn bird: I/O loop cycle took 5328 ms
>for 1 events
>Dec 21 12:38:54 router1 daemon.warn bird: I/O loop cycle took 5013 ms
>for 1 events
>Dec 21 12:39:07 router1 daemon.warn bird: Kernel dropped some netlink
>messages, will resync on next scan.
>Dec 21 12:39:14 router1 daemon.warn bird: I/O loop cycle took 5053 ms
>for 1 events
>Dec 21 12:39:34 router1 daemon.warn bird: Kernel dropped some netlink
>messages, will resync on next scan.
>Dec 21 12:40:14 router1 daemon.warn bird: I/O loop cycle took 5041 ms
>for 1 events
>
>[12:49] router1.place6:~# ip -6 r | wc -l; ip r | wc -l
>78212
>779342
>
>With "debug latency;" I get the following additional messages:
>
>Dec 21 12:54:31 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 4449 ms
>Dec 21 12:54:52 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 5608 ms
>
>The system is overall idle with bird spiking to 50-100% cpu usage every
>couple of seconds. I first thougt they are only logged after stating
>bird (where it might make sense), but the events continue to be logged
>around every 30s:
>
>Dec 21 13:04:11 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 4596 ms
>Dec 21 13:04:32 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 5096 ms
>Dec 21 13:04:52 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 5102 ms
>Dec 21 13:05:11 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 4676 ms
>Dec 21 13:05:31 router1 daemon.warn bird: Event 0x000055a21afb8144
>0x0000000000000000 took 4645 ms
>
>Which might loosely correlate to the scan time "20" that is setup for
>device and kernel protocols.
>
>How do I best debug this issue?
>
>Best,
>
>Nico
>
>
>
>--
>Modern, affordable, Swiss Virtual Machines. Visit
>www.datacenterlight.ch

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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