Subject: Re: [PATCH 0/2] NET: Accurate packet scheduling for ATM/ADSL

From: Patrick McHardy <[email-masked]>
Date: Tue, 20 Jun 2006 02:54:36 +0200

jamal wrote:
> - For further reflection: Have you considered the case where the rate
> table has already been considered on some link speed in user space and
> then somewhere post-config the physical link speed changes? This would
> happen in the case where ethernet AN is involved and the partner makes
> some changes (use ethtool). 
> 
> I would say the last bullet is a more interesting problem than a corner
> case of some link layer technology that has high overhead.
> Your work would be more interesting if it was generic for many link
> layers instead of just ATM.

I've thought about this a couple of times, scaling the virtual clock
rate should be enough for "simple" qdiscs like TBF or HTB, which have
a linear relation between time and bandwidth. I haven't really thought
about the effects on HFSC yet, on a small scale the relation is
non-linear. But this is a different problem from trying to accomodate
for link-layer overhead.