Re: Config understandings

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

On Tue, Oct 17, 2000 at 02:20:12AM -0400, John Klos wrote:
> IS wrote:

> > M68060=YES in /etc/mk.conf chooses a different libm to be built, and also
> > influences some of the big number aritmetic routines used by the ssh and
> > pgp packages.

> So you put the tuna WITH the mayo...

Sort of. Now, that I slept enough for two nights in a row, I can even remember
to explain why: Normal assembler-language bignum  routines for m68k like to use
the 32x32->64bit multiplication of m680[234]0, which was removed on the M68060
and causes a kernel trap. The compiler avoids it when -m68060 or -m68020-60
is given, but of course it has no idea that it should use different assembler
files (or none at all). Similar stuff happens when you use some floating point
routines that are written with the 6888[12] FPU in mind; they are trap-emulated
on 68040 and 68060, and using a specialized libm helps a lot here in some
cases.

> I rebuilt my RSAREF, OpenSSL, and OpenSSH, and startup of sshd dropped
> from about 60 seconds of CPU time to about 15 (comparatively, the same
> config on a 40 mhz 68040 Mac takes about 31 seconds).

I didn't look at RSAREF, OpenSSL and OpenSSH myself, but apparently somebody 
else did.

It was a factor-of-10-improvement in startup time to pgp2 and sshd, when
I made the change.

> In the last two weeks (up until I restarted ssh), the main sshd daemon had
> accumulated over 130 minutes of CPU time.

Yesyes. the m68020-40 ssh-1.2.26 sshd needs about 2 minutes of startup time
on a 50 MHz M68060, and another two minutes each time the session startup
key is recalculated.

> Which leads me to another question: no matter how long the machine is
> idle, the load average never drops below 1.08 (yes, I'm running the
> distributed.net client).

Are you running xload or some similar applications? They chew up some 
cpu time for themselves as well as in the X server, which is not noticable
in todays standard Pentium or PowerPC machines, but noticable on <= 50 MHz
m68k.

Regards,
        Ignatios