Hi
On 08/25/05 17:19, Felix Schulte wrote:
What is the reason for having the cpuids 512 apart? Just bit mask
shifting?
Well we already had single-core cpus for which the numbering
scheme was established (depending on platform layout) and
there was a need to keep the old cpuid namespace distinct
from the additional part formed by adding multicore.
So SB0 on a 6800 has "always" had cpuids 0,1,2,3.
It nay have been nice to include the new sibling
cores as 4,5,6,7 but those numbers were expected
on SB1, by tradition. So, for these platforms
(SF6800 family, SUNW,Sun-Fire) the 512 difference
rule was established to jump over all possible
exisiting cpuids.
On a V880, by contrast, we only ever had cpuids
0-7. So when they became dual-core in the V890
we had a much smaller jump:
========================= CPUs ===============================================
Run E$ CPU CPU
Brd CPU MHz MB Impl. Mask
--- ----- ---- ---- ------- ----
A 0, 16 1200 16.0 US-IV 2.4
B 1, 17 1200 16.0 US-IV 2.4
A 2, 18 1200 16.0 US-IV 2.4
B 3, 19 1200 16.0 US-IV 2.4
C 4, 20 1200 16.0 US-IV 2.4
D 5, 21 1200 16.0 US-IV 2.4
C 6, 22 1200 16.0 US-IV 2.4
D 7, 23 1200 16.0 US-IV 2.4
And how is this related to the mythical "Sun Fire-Link"
product?
Not that mythical - you used to be able to order it and I know
of one site with I think 8 Starcats all linked via this.
The numbering choice likely had something to do with
this interconnect, but I'm pleased to say I don't know
the details :-)
Cheers
Gavin
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