Possible evidence of performance regression for 8.1-S (vs. 7.1)

David Wolfskill david at catwhisker.org
Tue Oct 26 11:29:17 UTC 2010

On Mon, Oct 25, 2010 at 10:09:53PM -0700, Julian Elischer wrote:
> ...
> >It appears to me that the last test runs show results that are just
> >about identical to the "native" 8.1-S kernel+userland, so if I
> >understand the logic correctly, that appears to implicate something in
> >the 8.1-S kernel (or the default configuration for same).
> yes,  exactly.

Good to get confirmation; thanks.  :-}

> however the interesting thing is that while it took more wall-clock time,
> it took less system and user time.

Aye; Dan Nelson also pointed that out, and it is rather interesting.

> you might try the 4bsd scheduler to see what that does..

OK -- but we were using the default scheduler in each case.  The basic
point I'm making here is the apparent performance regression for
similarly-configured systems under 7.1 vs. 8.1.

> also, compare the configs of the two kernels

Well, under 7.1, we used the MAC kernel config; since that didn't exist
for 8.x, I used GENERIC for it.  (We had used GENERIC under 7.1 until a
certain application we use required MAC support.  I haven't tried to
make that application work under 8.x yet, as there are plans to
deprecate its use.)

David H. Wolfskill				david at catwhisker.org
Depriving a girl or boy of an opportunity for education is evil.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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