6. DATA SOURCES › 6.8 PR/SM LPAR Concepts › 6.8.2 How PR/SM Works › 6.8.2.1 Introduction to LPAR CPU Management › 6.8.2.1.2 WLM LPAR Vary CPU Management

6.8.2.1.2 WLM LPAR Vary CPU Management

This function allows WLM to dynamically vary unneeded
standard CP processors offline.  It means that, from RMF
perspective, a standard CP processor can actually be online
to a partition for only a portion of its recording interval,
instead of the complete interval duration as before.  The
immediate impact of this capability is that, for WLM managed
logical partitions, the reported number of standard CP
processors for an LPAR is not the number of defined
processors anymore, but the number of online (in fact,
actually assigned by WLM) standard CP processors. This value
can be fractional.

But, the most important change is in the definition of the
"CPU Time," and hence, the way CPU busy calculations are
performed:

Before IRD:
-----------

CPU Time = Interval Time - Wait Time

and
                      CPU Time
CPU (%)  = ------------------------------ * 100
           Interval Time * No. Processors

After IRD:
----------

CPU Time = Online Time - Wait Time

and
                      CPU Time
CPU (%)  = ------------------------------ * 100
                     Online Time

The SMF type 70 subtype 1 CPU Activity record provides the
time, within the RMF interval, when a processor was online to
the logical partition (SMF70ONT).  From CA MICS perspective,
all data elements representing online times come from this
raw field, which is always available, whether the LPAR is
managed by WLM or not.