Re: Performance Manager (V3R2)

Performance tuning using the QPFRADJ for most sites is probably better
than doing a coin toss to determine what the value for activity levels,
pool sizes, priority, and other work management values should be. In one
of my performance presentations, I compare performance tuning to
building a house.  If you think of Pool sizes, Priority, activity
levels, time slice, and equate those to be the second floor of a house. 
How many houses have you seen where they build the second floor prior to
building the first, or before laying the foundation? Start with the
foundation -> Sharing of Access Paths, Reorganization of Physicals,
Resequencing of Data by most used Access Paths, program optimization,
deletion of spool files, and cleaning up other objects that you don't
need; these all need to be completed first. While these tend to take
many hours, days, weeks, or months depending on your size to complete
manually, there are software packages that can do these for you
automatically.   Otherwise you are throwing good (expensive) resources
after inefficient applications, to have them work properly (at the
expense of your entire system).  

So think about this example, if I have a physical file that we will read
sequentially and it is half full of deleted records, we can assume that
for every page we bring into memory, we will only read half the records
in the page. You can improve performance in one of two ways: 1) We move
more memory into that Storage Pool, which will reduce the paging in that
pool. or 2) Reorganize that file, so we get better utilization of memory
(we read all the records we bring into memory), if we have expert cache
on this improves things even more. In addition, this will reduce the
amount of physical DISK I/O, and the memory we would have moved into
that pool can be used by other applications.  

 In the above example number 1 is much easier, but option 2 will give
you much better results individually for that program and for the entire
system performance.  I know this works, because this is exactly what one
of the hundreds of functions that our software package OS Director
performs, and we have over 500 customers doing this very successfully.

  My recommendation is that people start with the foundation, but  I
would rather see people turn on Performance Adjustment for a short time,
than to do absolutely nothing.   How many times have you heard the
system performed so well when we received it, but now after one year it
is starting to get slow.  Well the CPU is not getting slow, its clock
rate is pretty constant, its the lack of Systems Management that has
made the system not perform as efficiently as it should.  

 JMHO,
Pete Massiello
OS Solutions International 
Phone: (203)-744-7854  Ext 11.
http://www.os-solutions.com
mailto:pmassiello@os-solutions.com
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