[j-nsp] spmb/ssb/feb/... memory usage details?

[Pekka Savola]

On Thu, 8 May 2008, Pekka Savola wrote:
> You can use the 'show chassis spmb/feb/ssb/...' to view DRAM memory
> utilization on the switch board.
>
> How can you find out what's taking DRAM memory?  'show route summary'
> on 'vty ssb' (or similar) shows how much your routing table takes but
> that's all I can find out.
...

I found some clues, the best reference was this:

http://puck.nether.net/pipermail/juniper-nsp/2005-May/004275.html

(though it'd be nice to be able to see how much uKernel heap takes)

Some others of interest:

http://www.mail-archive.com/juniper-nsp@puck.nether.net/msg01961.html
http://www.ip6.atm.tut.fi/list-archive/juniper-nsp-2005/msg00567.html

In this case, routing table is taking some 19M, route options 
(assuming 40B/entry) some 10M, radix trees some 5M, ARP is basically 
zero.  Observing on an empty system, the heap usage is 20% at 11M. 8M 
is uncached.  So, there's still about 9M unaccounted for.

(It's also not obvious to me why RPF requires an entry for each 
routing table entry if you run it in strict mode, smells like a badly 
implemented feature..)

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings