bad NFS/UDP performance

[Danny Braniss]

> > On Fri, 26 Sep 2008, Danny Braniss wrote:
> > 
> > > after more testing, it seems it's related to changes made between Aug 4 and 
> > > Aug 29 ie, a kernel built on Aug 4 works fine, Aug 29 is slow. I'l now try 
> > > and close the gap.
> > 
> > I think this is the best way forward -- skimming August changes, there are a 
> > number of candidate commits, including retuning of UDP hashes by mav, my 
> > rwlock changes, changes to mbuf chain handling, etc.
> 
> it more difficult than I expected.
> for one, the kernel date was missleading, the actual source update is the key, so
> the window of changes is now 28/July to 19/August. I have the diffs, but nothing
> yet seems relevant.
> 
> on the other hand, I tried NFS/TCP, and there things seem ok, ie the 'good' and the 'bad'
> give the same throughput, which seem to point to UDP changes ...
> 
> danny

Grr, there goes binary search theory out of the window,
So far I have managed to pinpoint the day that the changes affect the 
throughput:
	18/08/08 00:00:00 	19/08/08 00:00:00
(I assume cvs's date is GMT).
now would be a good time for some help, specially how to undo changes, my
knowledge of csup/cvs are close to zero.

danny