> > Perhaps someone could at least run a benchmark to measure this
> > effect on two otherwise identical systems with two different OS
> > releases installed, say 1.4.3 vs. 1.5?
>
> I have just set up such a machine:  MVII, 13mb ram, 4x 1 gig identical
>                                     scsi drives, 1.4.3 generic and
>                                     1.5 generic loaded on individual
>                                     drives with room for 2 more setups
>                                     using stripped kernels.
>
> IF someone will send me what is considered to be the most highly stripped
> and bare and fastest MVII kernel config, I will run that up on 1.4.3 and
> 1.5 on the other two disks.  You gurus decide what is needed.  The
> config must contain tk50, deqna, radisk and ka630 support, and really
> nothing else.

I don't think the size of the kernel matters all that much speed-
wise, unless you are severely memory restricted.

What's otherwise the important thing is to run a kernel config
that's comparable (as few differences as possible) on the two
releases.

I think I would recommend you run lmbench on the two systems, and
merge the results (give them different names so that the results can
be summarized in a single table for easy comparison).

And of course any other relevant benchmark you can think of which
excercises the kernel/user interface in various ways.

As for the interpretation and explanation of the results I'm not
qualified to comment, but it does at least help to have some
measurements to rely on.  As an aquaintance of me say: "pair in
facts beats a full house of suppositions".

However, as long as suppositions and rumours is all we're
discussing, yes, I seem to remember others mentioning that something
also changed on the path to 1.5 in the network stack which caused
worsening in the performance, especially noticeable on slow
machines.  However, that's probably a different issue than the one
we're discussing above.

Regards,

- H=E5vard