2. PERFORMANCE REPORTING ANALYSIS › 2.7 Graphic Analysis › 2.7.5 Paging Graphs › 2.7.5.2 Response Time for Local Page Data Sets

2.7.5.2 Response Time for Local Page Data Sets

GRAPHIC RESULTS

This graphic analysis provides a multi-line plot of response
times for all local page data sets.

ANALYSIS GUIDELINES

Local page data sets can experience paging loads from a
variety of sources:  demand paging, swapping, Hiperspace
migration, and virtual I/O.  Some of this paging traffic is
asynchronous, that is, no application is waiting for the
page's arrival before it can continue.  Some, however, is the
result of page faults and will cause the application to have
its processing suspended until the page has arrived in
processor storage.

With the advent of block paging, which first became available
with MVS/ESA SP 4.2, some of this demand paging may lead to a
presumptive decision by the Real Storage Manager (RSM) to
move into central storage for an address space all pages that
meet two criteria:  they were previously located in
contiguous virtual memory locations and they all had the same
unreferenced interval count (UIC) value.  This is a heuristic
attempt to predict page reference patterns and prepare for
them.  Initiation of block paging is load dependent, so you
may see not only the quantity of pages per unit of time
increase during peak loads, but you may also see the nature
of the paging work change from short bursts to larger blocks.

The detailed behavior of the paging subsystem can be further
analyzed using the Auxiliary Storage Management analysis
reports described in Section 2.2.