Re: NetBSD 4 strangeness

[Ignatios Souvatzis <is%netbsd.org@localhost>]

On Wed, Sep 06, 2006 at 11:12:48AM -0600, Michael L. Hitch wrote:
> 
> 
> On Tue, 5 Sep 2006, John Klos wrote:
> 
> > I've crossbuilt NetBSD 4 for Amiga with -m68060 specifically using gcc 4,
> > which has produced a working system for me. I will test whether the m68060
> > trapped instructions was the issue that made current run unusably slowly
> > later.
> 
>   The m68060 trapped instructions shouldn't make your system run as slowly
> as I seem to remember you mentioning before, unless something is running
> that is using an extremely high usage of those instructions.  If that were
> the case, then vmstat -i should show an extremely high rate of
> 'interrupts' for the m68060 traps.

systat vmstat shows 60intemu and 60fpiemu (and I think 60fpdemu) rates.
60intemu - if it's the multiplication - saturates my DraCo at a rate
of about 220000/s last I looked. Didn't test with -cur/-4 userland or
kernel yet.

ssh, pgp, generally all bignum-style arithmetics are using 32x32->64
multiplication unless you forbid them to do that which traps on the '60.

gcc before 4 tends to create them for division by constants unless
-m68060 is in effect, but you normally only see a handufl of them
(100/s-200/s 60intemu and 20/s-30/s fpiemu on www.de.netbsd.org with
a 4.0ish kernel and an older userland). I don't know what it would 
create that uses more of them in gcc-4; will have to look, or please
report which of the 60xxxxxx traps are excessive with a gcc-4 compiled
userland.

Regards,
        -is