Identifying BGP convergence bottleneck

[Patrick.deNiet at os3.nl]

Thanks for your info Ondrej, it's much appreciated!

I've done both unique, overlapping and identical prefixes on these peers.
The unique one costs the routeserver more memory than I had unfortunately.

I'll let you know if I have anything to share.

Regards,
Patrick


> On Thu, Jun 22, 2017 at 10:26:03AM +0200, Patrick.deNiet at os3.nl wrote:
>> Hi everyone!
>>
>> I am currently looking into the performance of BIRD (bgp) as a
>> route-server with ~700 peers with 10k prefixes each. I'm noticing an
>> increase in convergence time as I increase these numbers (which is not a
>> surprise).
>>
>> Unfortunately, I do not have a deep enough understanding of the code and
>> have not managed to identify these points. Is anyone here able to give
>> some pointers as to where in the code we could place these markings to
>> measure this?
>
> Hi
>
> It is hard to tell, esp. it depends on your setting and configuration and
> would need some benchmarking. It is single-table or multi-table route
> server [1][2]? Personally i would guess that it is in TX, because you
> receive a route and then send it about ~700 times (but that depends on
> whether prefixes from different peers are shared or unique). You could
> benchmark it with 'export none' to see the difference.
>
> Also note that hash table used for routing table has max size of 64k
> buckets. You could try attached patches to fix that. That may help
> significantly.
>
> I would be interested in your performance results.
>
> [1]
> https://gitlab.labs.nic.cz/labs/bird/wikis/Route_server_with_community_based_filtering_and_multiple_RIBs
> [2]
> https://gitlab.labs.nic.cz/labs/bird/wikis/Route_server_with_community_based_filtering_and_single_RIB
>
> --
> Elen sila lumenn' omentielvo
>
> Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
> OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
> "To err is human -- to blame it on a computer is even more so."
>