max CPUs and Cores per Cell in a SD

[Jdamian]

Hi

How many CPUs and Cores can a single SD cell have? The SD is a PA-RISC SD.

My SD partition have 4 cells. Each one has 4 CPUs PA-RISC 8800 (i.e., 8 cores).

The CSTM displays in each cell there are CPU slots empty:

CPU Info for Cell#....: 0
Max CPUs.........: 8
CPU Clock Domain.: 0
IODC_HVERSION....: 0x8800
cpu -------------------------------------------------
num |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|
cpu -------------------------------------------------
slot | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 |
-------------------------------------------------
state| c | c | c | c | s | s | s | s |
-------------------------------------------------
c - cpu is present and configured
d - cpu is present and deconfigured (CPU has failed)
s - cpu slot empty

Note that for each CPU slot there are 2 "CPU num" and there are 4 CPU slots empty

Can I add other 4 PA-8800 CPUs (8 Cores) to each cell?

I'm confused because my team mates say the maximum number of CPUs per cell is 4 and because parstatus reports the maximum is 8:

[Cell]
CPU Memory Use
OK/ (GB) Core On
Hardware Actual Deconf/ OK/ Cell Next Par
Location Usage Max Deconf Connected To Capable Boot Num
========== ============ ======= ========= =================== ======= ==== ===
cab0,cell0 Active Core 8/0/8 16.0/0.0 cab0,bay1,chassis3 yes yes 0
cab0,cell1 Active Base 8/0/8 16.0/0.0 - no yes 0
cab0,cell2 Active Base 8/0/8 16.0/0.0 - no yes 0
cab0,cell3 Active Base 8/0/8 16.0/0.0 - no yes 0

[Sherif A. Louis · Accepted solution]

PA8800 is a dual core processor
and yes the cstm shows a 8 CPUs for Cell #0 and physically the cell can only carry 4 Processor modules.

[Torsten.]

Each cell has space for 4 CPU modules, if they are dual-cores, you can have up to 8 cores on a single cell (Max CPUs.........: 8).

The cstm output is using the same table for all servers, this does not mean you have more free slots on a cell.

[Torsten.]

Some (older) non-cell based servers can have more CPUs and slots, it would look like this (this is a N4000 server):

CPU Information:
Number of CPUs in the system = 8

CPU Map
cpu -----------------------------------------
slot | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 |
state|caM |ca |ca |ca |ca |ca |ca |ca |
-----------------------------------------
| 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 |
state| | | | | | | | |
-----------------------------------------

[Jdamian]

Then, CSTM cannot differentiate a SD cell from a non-partitionable main board and displays unaccurate info?

[Torsten.]

Everything is accurate, only the table is a bit too large.

Your system says

CPU Info for Cell#....: 0
Max CPUs.........: 8

Your cell 0 can have up to 8 cores (4 modules) and this is what you have.

[Jdamian]

I'm sorry but I don't agree.

1. I have 4 CPUs (8 cores) but I have NO CPU slot empty. CSTM reports there are 4 CPU slots empty. That is false.

2. What does the word "CPU" mean in the CSTM output? Either "Cores" or "Chip-level multiprocessors"?

[Torsten.]

It is a fact that each cell for every cell based server has 4 slots. Each slot can take a CPU module, either single core or dual core (or even a "dual single core" with the very special Itanium Hondo CPU).

4 slots are maximum.

Some tools are counting cores, some other are counting modules - unfortunately.

In this case the 8 means cores.


Some things in a superdome may be based on historical develeopment plans, but never released.

An early superdome with an old version of STM still tells about a maximum of 16 cabinets - never released, but probably planned.

If you take a closer look, you will see the cabinet is prepared for 6 slot I/O chassis - never released.

Simply trust all the tools telling you about a maximum of 8 CPU cores per cell if you use dual-core CPUs (cstm, parstatus, etc all telling the same).

If you don't trust them all, rip out a cell and take a look ... ;-)

[Jdamian]

.