Identifying BGP convergence bottleneck

[Ondrej Zajicek]

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."
-------------- next part --------------
A non-text attachment was scrubbed...
Name: update-hashing-1.patch
Type: text/x-diff
Size: 1914 bytes
Desc: not available
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20170628/ed8dd399/attachment.patch>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: update-hashing-2.patch
Type: text/x-diff
Size: 386 bytes
Desc: not available
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20170628/ed8dd399/attachment-0001.patch>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20170628/ed8dd399/attachment.asc>