Re: [PATCH/RFC] [v3] TCP: use non-delayed ACK for congestion control RTT

[Gavin McCullagh <Gavin.McCullagh@nuim.ie>]

On Sun, 30 Dec 2007, Ilpo Järvinen wrote:

> I guess the non-minimum TSO delays are only significant in case there was 
> something unexpectional happening and in such case we definately want to 
> have some measurements taken.

Broadly speaking, delay-based schemes need as much information about the
queueing delay as possible so more points are generally useful,
particularly if the delay is fluctuating rapidly.

When we started looking at delay-based schemes we had trouble with delay
information fluctuating wildly due to TSO.  John Heffner made a change
(that I can't find at the minute) which reduced a TSO timeout and seemed to
reduce this problem greatly.  It's worth bearing in mind though that TSO
may cause spuriously high delay measurements.  

Gavin