On Mon, 19 Jan 1998, John Carol Langford wrote:
> >The question is, would this incur significant overhead at high speeds?
> >Wouldnt just multipath+no-route-cache be better at e.g. 10mbps?
>
> Depends on the cpu. For a rough rule of thumb, ipeql on a Ppro-200
> multipathing between 2 fast ethernet cards would just saturate the cpu.
> One saturated fast ethernet card would consume about 30%-35% of the cpu.
>
> If ipeql incurred no overhead (currently due to an extra layer of indirection
> and not using the route cache), you would expect 60-70% cpu utilization.
>
> Most of the extra 30-40% overhead is (I expect) due to losing the route cache.
> The extra overhead may be acceptable on a fast cpu using only 10Mbps
> connections.
>
> The "best" solution would be to not waste the route cache - something which
> doesn't seem possible just in the realm of a device driver. Alterations to
> the IP stack changing the way hardware header caching is done would be
> necessary.
>
> -John Langford
>