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New processor PA-RISC8800 dual CPU: How many processors does a "top "command display?

 
Romaric Guilloud
Regular Advisor

New processor PA-RISC8800 dual CPU: How many processors does a "top "command display?

Hello,
The new PA-RISC PA8800 is a dual-core processor available on Superdome.
Assuming I create one n-Par made of one cell (4 processors PA-8800 by cell), how many processors will be displayed at the top command (or ioscan) under HP-UX running on this n-Par.
I was thinking 4, but figured out that IBM with its Power4+ (dual-core processor as well) provides higher granularity by showing the 2 sub-CPUs of the processor as processors themself.
Got it?
Any link, URL, info highlighting this concern is welcome.
Thank you.

Romaric.
"And remember: There are no stupid questions; there are only stupid people." (To Homer Simpson, in "The Simpsons".)
2 REPLIES 2
Oleg Khoroshylov
Frequent Advisor

Re: New processor PA-RISC8800 dual CPU: How many processors does a "top "command display?

Hi,

I think "top" should show number of cpu = number of cores, i.e. 8 cpu's for one cell.
That's because single core of PA8800 is in fact a separate PA8700 cpu. As consequence of this for example when you buy licenced per processor software each core of PA8800 is considered as separate cpu.

See below link showing PA-8800 design:
http://www.lostcircuits.com/cpu/hp_pa8800/

BR,
OK
No RISC, no fun
Ted Buis
Honored Contributor

Re: New processor PA-RISC8800 dual CPU: How many processors does a "top "command display?

The pa-8800 has two separate CPUs on one chip. The 32MB L2 cache is shared, but each CPU has its own 1.5MB L1 cache. This is quite different from Intel's Hyperthreaded processors which share execution logic.
Mom 6