[rescue] e4k / 250/1mb cache vs 250/4mb cache

[Mike F]

On Sat, Oct 09, 2004 at 07:43:52PM -0700, Skeezics Boondoggle wrote:
> On Fri, 8 Oct 2004, Steven Hill wrote:
> 
> > Anyway, I have 4x250 and 2x400 running happily.
> 
> Out of curiosity, what does prtdiag -v show on your machine?
> 
> I was under the impression that until the Ultra-III-based systems came
> out, mixing speeds was officially unsupported, and even if it does happen
> to work, the system simply finds the least common denominator - clocks
> down the faster CPUs to match the slowest ones, and ignores any larger 
> caches than the smallest.
> 
> I'm almost positive that was true of, say, the sun4d and sun4m boxes; put 
> an SM51 and an SM61 in a Sparc 20 and it'll run them both at 50Mhz.  Put 
> some SM81's in an SC2000 with some SM81-2's, and it'll just ignore the 2nd 
> meg of cache on the larger modules.
[snip]

For no other reason than the fact that I'm cheap, I'm running a 
SPARCStation 20 with an SM71 and an SM51. prtdiag doesn't work on SUN4M 
systems, but here's what `psrinfo -v` reports:

Status of virtual processor 0 as of: 10/12/2004 10:32:41
  on-line since 06/05/2004 02:10:43.
  The sparc processor operates at 75 MHz,
        and has a sparc floating point processor.
Status of virtual processor 2 as of: 10/12/2004 10:32:41
  on-line since 06/05/2004 02:10:47.
  The sparc processor operates at 50 MHz,
        and has a sparc floating point processor.

These modules both have 1MB of cache, so I can't say what would happen 
with differing caches, but it does seem to maintain differing processor 
speeds.
- Mike