Re: 4.01 panic/lock issues?

[Bolo <bolo%cs.wisc.edu@localhost>]

> > Anyway, using -m68040 on building packages is too bad..
> 
>       I believe that the performance penalty of -m68020 on 040 boxes
>       is great enough that there is real benefit for using -m68040.
>       Defaulting to -m68020-60 would reduce that need significantly...

Another way of looking at this is that the most common 68k boxes
are the 020 and 030 boxes.  The 040s and 060s, though wonderful,
are comparatively rare.

The performance loss of instruction emulation will effect the slower
machines far more than than the faster boxes, it costs less to emulate
when a faster CPU is doing the emulation.

We ran a combined 020/030/040 userland (020 + 6888[12]) for a number
of years.  The performance effects of the emulated instructions on
the 040 never made a real difference in performance -- they were
still the fast kids on the block by a large margin.

Specialized workloads which hit the emulated instructions a lot could
change that.  However for ordinary system / unix / software development /
math / text processing type things there was no noticeable performance
loss with the fast machines emulating the "slow" instructions.

Bolo