Number of cores

UNIX AIX
1

Hi,
On AIX 7.2
When I run:
lparstat
I have:
System configuration: type=Shared mode=Uncapped smt=4 lcpu=4 mem=16384MB psize=5 ent=0.20

Considering lcpu=4 , does it mean that I have 4 cores?

Is lparstat the right command? If not what else?

Thanks and regards.

2 
lcpu
Indicates the number of online logical processors

See Also:

https://www.ibm.com/docs/en/aix/7.2?topic=l-lparstat-command

1 Like
3

Thanks.
How can I see number of cores?

Regards.

4

The article
How to get Physical processor count on AIX | AIX.
suggests

prtconf
lparstat -i

The "active physical processors" are the cores.
Where the effectiveness of a core depends on the CPU model.

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5

Thank you.
The following seems the solution:

 lparstat -i | grep "Online Virtual CPUs"

Regards.

6

The man page posted above also yields:

Screen Shot 2022-10-11 at 6.37.49 PM

Sometimes taking a minute or two to read the man page can save you a lot of time and energy.

Looks like @MadeInGermany read the man page for you @big123456 .

From the man page posted above:

Screen Shot 2022-10-11 at 6.41.42 PM

See also:

Screen Shot 2022-10-11 at 6.43.05 PM

7

Hi Neo,
Thank you.
The problem is definition of CORE.
Unless mistaken, I do not see CORE in your extraction of man page.
Best regards.

8

core, cpu or processor, these are the same thing (according to the blog post below..... )

Reference:

9

Thanks.
No one knows the TRUTH.
lparstat -i | grep "Online Virtual CPUs"
Online Virtual CPUs : 1

image

And above we have:
image

Best regards.

10

LOL

What CPU model is in your AIX box?

If you do not know then you can open the box and look on the CPU.

Also, what is the output of

prtconf

??

Reference:

https://www.ibm.com/docs/en/aix/7.2?topic=p-prtconf-command

See Also:

https://www.unix.com/aix/248461-finding-type-aix-server-using-command-line.html

11

Your lpar is configured as Shared / Uncapped.

So if you are looking to how many cores this lpar has access (as the physical cpu's are shared) the answer is : 1 core, also called i physical cpu or 1 virtual cpu. Because you are using SMT mode 4 it means that 4 threads of execution can run in parallel on that single core. AIX needs to schedule a thread on a cpu this is why the 1 virtual cpu gives us 4 logical ones. If you run a workload you are entitled to 0.2 meaning that you will always receive 0.2 physical cpu's worth of time even if the shared pool is very busy. When there are enough free cycles in the shared pool, your setup can utilize op to 1.0 physical CPU (so 500% of entitlement). Also note that in the current setup even though your are uncapped you are actually "Capped" by the 1 virtual cpu (1 virtual cpu cannot use more then 1.0 physical cpu).

1 Like