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SYSVIEW - Details on MVS CPU Display

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Article ID: 189832

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Updated On:

Products

SYSVIEW Performance Management NXBRIDGE - SYSVIEW/ENDEVOR

Issue/Introduction

Some additional information on the MVS CPU display 

  1. For the General CP(s) being shown, are these supposed to represent the Logical CP(s) or the Physical CP(s)? 
  2. If the GCP(s) represent Logical CP(s) are the PARKED / UNPARKED designations "truly" representing a Physical CP being PARKED or UNPARKED to the LPAR; or the dispatching of a Logical CP to a Physical CP.  If PARKED and UNPARKED is not representative of Physical CP(s), what is the meaning in SYSVIEW relative to Logical CP(s).
  3. If the GCP(s) represent Physical CP(s); how does SYSVIEW take into account other LPAR(s) also accessing the same Physical CP(s) (Note:  I have a z14-610 with 11 LPAR(s) ACTIVATED & 9 OPERATING with 33 Logical CP(s) defined between them.)? 
  4. What is the data refresh rate for the information that SYSVIEW is showing?  I know when I hit the [ENTER] key, if the systems responds quickly, I can see a change in data as fast as I can depress [ENTER], down to around 2 seconds.  What am I "really" seeing relative to when I hit the [ENTER] key.
  5. We know that millions of instructions/actions take place every second.  There is much that occurs in those "2" seconds that we never see, including PARKING and UNPARKING of CP(s).  Does/How Does SYSVIEW "roll up" the data it acquires in its sampling data?  Does it "roll-up" data or does it only present want it see at the particular "moment".

A user can watch the PARKED / UNPARKED status of the CP(s) and believes that additional CP(s) should be UNPARKED for one of the LPAR(s).  Trying to access exactly what SYSVIEW is representing in this particular display it can be compared  with what is known of how PR/SM works with the PARKING/UNPARKING of CPs and PR/SM Weight Management.

Environment

Release : 16.0

Component : SYSVIEW

Resolution

In the MVS CPU display, SYSVIEW is displaying CPU data as reflected in the z/OS LPAR's Communications Vector Table (CVT) and subsequent system control blocks. Essentially, the data showed in the CPU display is representation of how a z/OS LPAR views the CPUs at a given point in time. Keep in mind, one LPAR might see the CPU metrics differently than another LPAR even though they're running on the same hardware.

Using the CA Common Communications Interface (CAICCI) component of CA Common Services (CCS).

The answers to the actual questions :

1 . This depends on how the LPARs and the hardware are configured in relation to whether Simultaneous Multi-threading (SMT) is enabled or not.

     SYSVIEW identifies this in the CPU (non-xsystem) command overview section - View information field

   +------------------+--------------------------------------------------+
   | View             | The processor view. Possible values are:         |
   |                  |                                                  |
   |                  | CPU - A processor represents a single CPU.       |
   |                  |                                                  |
   |                  | CORE - Simultaneous Multithreading (SMT)         |
   |                  | is enabled. A CORE represents                    |
   |                  | multiple CPU's, or threads.                      |
   +------------------+--------------------------------------------------+

2. The PARKED/UNPARKED designations are displayed as how a z/OS LPAR sees the CPs at that point in time and as indicated in the z/OS Logical Configuration Communication Area (IHALCCA).
    This question should be asked at IBM as to what those designations mean when the CPs are logical or physical.

3.  The previous comments answer this question.
     Essentially, the data in the CPU command display is shown from the point view of each LPAR.
     Keep in mind, one LPAR might see the CPUs differently than another LPAR running on the same hardware.

4.  The data displayed is an instant snapshot of the current state of the CPUs when hitting the [ENTER] key. It's a point in time collection of data.

5. The CPU MVS command display only presents CP data at the particular "moment". No "roll-up" is done for CPU metrics since that would imply monitoring every single instruction/action.