Re: RFC: NAPI packet weighting patch

[jamal <hadi@cyberus.ca>]

On Tue, 2005-07-06 at 14:06 +0200, Martin Josefsson wrote:

> One thing that jumps to mind is that e1000 starts at lastrxdescriptor+1
> and loops and checks the status of each descriptor and stops when it finds
> a descriptor that isn't finished. Another way to do it is to read out the
> current position of the ring and loop from lastrxdescriptor+1 up to the
> current position. Scott Feldman implemented this for TX and there it
> increased performance somewhat (discussed here on netdev some months ago).
> I wonder if it could also decrease RX latency, I mean, we have to get the
> cache miss sometime anyway.
> 

The effect of Scotts patch was to reduce IO by amortizing it on the TX
side. Are we talking about the same thing ? This was in the case of TX
descriptor prunning? 
So it is possible that the e1000 is doing more than necessary share of
IO on the receive side as well.

cheers,
jamal