polling(4) rocks!

[Eugene Grosbein]

On Wed, Nov 17, 2004 at 09:13:51PM +0300, Yar Tikhiy wrote:

> The router box is a 1.4GHz Celeron PC with an fxp(4) interface split
> across a dozen of vlans.  There is nothing special about its setup
> except for ~250 rules loaded into ipfw2.  It is running 4.10-RELEASE.
> Without polling, it was able to switch full 10Mbytes/sec of traffic
> (~9kpps), but that took from 50 to 70% CPU time spent in interrupts.
> With polling on, interrupt time never exceeds 5% and it stays as low
> as 1-2% on average even when traffic is that high.

Does polling(4) increase latency? It is very imortant for router
that handles lots of RTP (VoIP) traffic.

Eugene