[Xorp-hackers] memory consumption of xorp_bgp

[Marko Zec]

On Wednesday 18 April 2007 02:22, Yi Wang wrote:
> Hi,
>
> I was wondering if there is a way to reduce the memory consumption of
> xorp_bgp.
>
> My recent tests showed a setup of a XORP BGP instance (version 1.4)
> with:
> - 2 eBGP peers (each dumps the full ~200k routing table) and 30 iBGP
> peers (not exporting any routes) needs 1.25GB memory;
> - similar setup with 2 eBGP peers and 50 iBGP peers requires 1.91GB
> memory;
> (- similar setup with 20 eBGP peers and 1 iBGP peer requires 2.58GB
> memory).
>
> This makes my 3.6GB RAM box challenged to do emulations of a
> reasonably larger scale,
> such as 10 eBGP peers (~2M routes in total) and 100 iBGP peers.
>
> I was wondering if there is (relatively simple) way to reduce the
> memory consumption
> of xorp_bgp?  I understand there are more than one copy of each route
> stored, such as
> ribIn_table, cache_table (import and export branches), and
> aggregation_table.  But
> I'm not sure if I found all the permanent storages (probably not).
>
> Any hints / advices?

After 1.4 was released I commited a small change which should reduce the 
memory consumption of BGP by roughly 10%, so you might try repeating 
your experiments with the most recent code from CVS and report what 
happens.

Another thing that you might try would be decoupling the last route 
caching stage that stores outbound prefixes on each peering.  This 
would probably result in a more dramatic reduction of BGP's memory 
footprint.  The attached patch should do the trick, but be warned that 
it is completely untested :)

Cheers,

Marko



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