Re: Different speed CPUs show up as same speed

> > Wow - differing CPU clock speeds.  In most MP setups I know about that
> > would result in a lock up at some point in the future.

There is no real reason for it to lock up. It actually (probably)
tests your locking code slightly more thoroughly.
> 
> I'm surprised this boots at all. I thought both CPUs at least had to
> have exactly the same core. (identical "stepping".)

Only if you have a cpu (like the 68020) that stacks microcode
addresses in some of its exception frames - even then you
just need to ensure that such processes resume on the same cpu.
> 
> My impression was that the "symmetric" in _S_MP implied (among other
> things), that all CPUs were equal.

Just that they all have equal access to all memory.
(with some care you could build a SMP system that had CPUs that
executed different order code (provided the endianness and word
size were the same), kernel function pointers are slightly tricky)
> 
> Seems that some can be more equal than others.

There are certain bits of code that rely on the cpu speed
- so would need to be calibrated separately - eg the
drvusecwait() routine of SVR4.

	David

-- 
David Laight: [email protected]