6. DATA SOURCES › 6.6 Notes on RMF Samples › 6.6.2 Skipped Samples

6.6.2 Skipped Samples

The field SMFnnFLA in the RMF Product Section contains a bit
indicator, SMFnnISS, which, when set, means that RMF has not
taken samples for every cycle during the measurement interval
("nn" is the record type, and may be from 71 to 79; the type
70 CPU Activity record does not have this indicator).  Except
for the type 71 Paging Activity Record (discussed later),
there is no reason given for the skipped samples.  The data
elements "fffRSMP" will contain the actual number of samples
taken, so that calculations will continue to be accurate,
even if less statistically significant.

Many files in the CA MICS database that contain RMF sample
data elements also contains information on skipped samples.
In the DETAIL timespan, the data element fffISS contains the
value "Y" if samples were skipped during the RMF interval, or
"N" if not.  In all timespans, the data element fffISSCT
contains the number of RMF intervals with skipped samples
that were used to create the summarized observation (in the
DETAIL timespan, fffISSCT will have the value of 0 or 1).
The only exception to this is the HARCPU file because the
type 70 Record does not have a skipped samples flag.

The type 71 Paging Activity Record contains not only the
SMF71ISS flag, but also two fields recording the number of
samples skipped due to negative calculations or count
failures.  These are recorded in the SCPPAG file as data
elements PAGSKNEG and PAGSKCNT, respectively.  These skipped
samples only affect values describing private or CSA+LPA
fixed-frame allocations, and not any other data elements in
the SCPPAG file.  The affected elements are:

PAGC PAGAVC PAGMNC PAGMXC
PAGR PAGAVR PAGMNR PAGMXR

For convenience, a data element whose value is equal to the
normal total sample count less samples skipped has been added
to the SCPPAG file.  This data element, PAGRSMP2, is
calculated by means of the formula:

PAGRSMP2=SUM(PAGRSMP,(-PAGSKNEG),(-PAGSKCNT);