huge difference with device polling enabled with realtek nics

From:	Adam Gibson <agibson at ptm dot com>
To:	m0n0wall at lists dot m0n0 dot ch
Subject:	huge difference with device polling enabled with realtek nics
Date:	Mon, 23 Jan 2006 17:16:37 -0500

I was pushing about 5.5 MBytes/sec through a 400mhz Axiomtek NA-0041B 
(comes with 4 built-in realtek/rtl nics) and noticed that CPU usage was 
at 73%.  This is without any VPN overhead.  Traffic was passing from LAN 
to OPT1.  I then enabled device polling and CPU usage went down to 0% - 
1% during the same transfers.

I was rather surprised that a 400mhz system is barely able to keep up 
with 5.5MBytes/sec without device polling since that is the default. 
Has anyone else noticed this?