What is a command to check number of CPU/Cores AIX 6.1 OS running on. AIX is on PowerVM LPAR.

also,

lscfg -vp|grep WAY

lscfg -vp|grep proc

lparstat -i|grep ^Active\ Phys

Thank you ddup,

1. Could you explain how definition of virtual CPUs/cores is done in PowerVM. For example is it possible to define a one quad core CPU for LPAR if the physical CPU in IBM box is dual core? Or is it possible to define two Dual Core CPUs for LPAR if the total number of physical CPU in IBM box is one Dual Core?

Im not talking about performance is such scenarios. I just want to understand the logic behind it.



2. Could you comment each line in the following AIX response to lparstat -i | grep CPU. Is that responce from AIX running on LPAR?

Online Virtual CPUs : 2
Maximum Virtual CPUs : 15
Minimum Virtual CPUs : 1
Maximum Physical CPUs in system : 2
Active Physical CPUs in system : 2
Active CPUs in Pool : 2
Physical CPU Percentage : 25.00%

1. I'm sorry, not sure what are you asking... If you have 1 16-way core it means you have 16 processors in the same core. You can't do much with cores actually, it's just the way it's build. So let's just forget about it. The 16 processors you can split either way you want to between your LPARs. With Advanced micro-partitioning enabled you can even split as less as 1/10 of a CPU to a LPAR. All that is done on HMC level. On the LPAR under AIX (or Linux) you will just see CPUs (processors). If you enable SMT it can present those fractions of those physical processors as a single separate processor to drive utilization up, if an application is multithreaded or it's many of them, either way. If it's a single application that is single threaded - SMT can degrade performance.

2. The most of it is properties of LPAR defined on HMC.

http://publib.boulder.ibm.com/infocenter/systems/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds3/lparstat.htm

Online Virtual CPUs
    Number of CPUs (virtual engines) currently online.
Maximum Virtual CPUs
    Maximum possible number of CPUs (virtual engines).
Maximum Physical CPUs in System
    The maximum possible number of physical CPUs in the system containing this LPAR.
Active Physical CPUs in System
    The current number of active physical CPUs in the system containing this LPAR.
Active CPUs in Pool
    The maximum number of CPUs available to this LPAR's shared processor pool.
Shared Physical CPUs in system
    The number of physical CPUs available for use by shared processor LPARs.
Physical CPU Percentage
    Fractional representation relative to whole physical CPUs that these LPARs virtual CPUs equate to. This is a function of Entitled Capacity / Online CPUs. Dedicated LPARs would have 100% Physical CPU Percentage. A 4-way virtual with Entitled Capacity of 2 processor units would have a 50% physical CPU Percentage.

In PowerVM world can Physical CPU Percentage be more than 100%? Or in other words can one Virtual CPU equate to 2 physical CPUs?

Hi,

one virtual CPU can be mapped to one physical CPU at most.

The Physical CPU percentage is calculated by dividing the entitled capacity by the number of online virtual CPUs.

This means, that when exactly the entitled capacity would be used, that many percent of a physical CPU would be consumed.

This value can not be greater than 100%, because, as said above, it's not possible to consume more than one physical CPU per virtual CPU.

With uncapped LPARs more than the entitled capacity can be used ("%entc" in "lparstat"), this will then lead to more than 100% of a physical CPU being consumed, given there is more than one virtual CPU online. This is not reflected in "lparstat -i" (it's a static view), but with "lparstat" alone, (the dynamic view) as "physc". This is not a percentage, however, but an absolute number.

wmp

Thank you Woolmilkproc for your input& I was about to understand the idea until I started to read your last paragraph
Could you come again from "With uncapped LPARs"?