linux# netstat -rn or bird> route show strangeness

[Arjan Filius]

Gentz,

an update.
it's not bird related.

even a:
linux# time dd if=/dev/zero  of=/dev/zero count=10000000
has a big difference in time on both machines, even when bird is not 
running.
so don't know yet what it is , but not bird at all.

Sorry for disturbing you.

Regards,

Arjan Filius


On Thu, 3 Jun 2010, Arjan Filius wrote:

> Hello,
>
> today i noticed huge difference between our 2 identical bgp ubuntu 10.04 LTS 
> with burf 1.2.3 (ppa) x64 routers. (hardware DL380G6 12G ram X5560  @ 
> 2.80GHz)
> systems are still idle in having no ip traffic yet, except for the bgp 
> sessions and "random" other traffic.
>
>
> root at snxbgpprd01:~# time netstat -rn |wc -l
> 318259
>
> real	0m1.296s
> user	0m0.950s
> sys	0m0.390s
>
> root at snxbgpprd02:~# time netstat -rn |wc -l
> 318263
>
> real	0m9.079s
> user	0m6.720s
> sys	0m2.500s
>
>
> with linux ip route:
> root at snxbgpprd01:~# time ip route show |wc -l
> 318267
>
> real	0m1.152s
> user	0m0.490s
> sys	0m1.040s
>
>
> root at snxbgpprd02:~# time netstat -rn |wc -l
> 318263
>
> real	0m9.079s
> user	0m6.720s
> sys	0m2.500s
>
>
> and with bird:
> root at snxbgpprd01:~# time echo "show route"  | birdc | wc -l
> 1229972
>
> real	0m3.315s
> user	0m0.510s
> sys	0m0.230s
>
> root at snxbgpprd02:~# time echo "show route"  | birdc | wc -l
> 896174
>
> real	0m20.018s
> user	0m2.050s
> sys	0m0.920s
>
>
> so asking the route table takes at least 7 times more on the second rtr, 
> while being exact the same hardware, OS and software. only other bird config 
> due to IX connections.
> with "debug protocols { states, routes , filters};" i didn't notice anything 
> special, and both routers seem more or less equal.
>
>
> with these times, i noticed that it seems that the cpu usage of bird rizes to 
> 100% as i do a netstat -rn  on the linux prompt.
>
> It looks like a route table access contention
>
>
> At one time, this morning, the netstat command exceded the 3 minutes, and i 
> finally killed it.
>
>
> Has anyone same experinces, or knows perhaps what is going on?
> i want to start with oprofile to have a more closer look what is going on, 
> and where that cpu time is consumed.
>
>
> Regards,
>
>

-- 
Arjan Filius
mailto:iafilius at xs4all.nl