[c-nsp] NPE-G1 vs NPE-G2; is it a scam?

Saku Ytti saku at ytti.fi
Fri Mar 19 15:33:33 EDT 2010


On (2010-03-19 10:20 -0700), Stephen Cobb wrote:

> Found what I was talking about...this may explain things:
> https://puck.nether.net/pipermail/cisco-nsp/2007-April/039999.html

Just to throw in some speculation, as people probably know NPE-G1 is MIPS
and NPE-G2 is PowerPC, so rather large change. Software routers tend to do
context switch between every packet at low volume, to minimize latencies,
so copy packet, lookup, copy packet and so forth, when CPU is starting to
be congested, you copy more the one packet before looking them up,
increasing latency slightly by scaling further. Maybe the new PowerPC
architecture has more expensive context switch and performance might be
rather linear with NPE-G1 until you're doing fewer context switches.

It would be interesting to see how latencies in NPE-G1 and NPE-G2 differ at
100, 200, 400, 800Mbps.

-- 
  ++ytti


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