Do I Upgrade My Processor?
Analysis with Utilization Software
Most computer users become aware of the inadequacies of their computer
when it appears to slow down. On-line response time may be getting
longer between transactions or it may be moving to the limit of
tolerance. Batch jobs may be taking more time than they used to
or maybe nighttime runs interfere with the daytime on-line work.
There are times when these situations happen quickly, but most often,
it is a gradual process.
The things that cause a computer system to be degraded are not always
a lack of processor power. Memory, disk, and data communications
need to be considered. In addition, the system has factors, buffers,
and many options that can be adjusted to improve performance. DMSII
users have several additional issues to consider from what other
users need to examine.
It is generally not a good idea to have the hardware vendor, who
wants to sell another processor to you, evaluate your current system.
The vendor's bias may not permit a thorough investigation into the
causes of current degradation or bottlenecks. An independent analysis
is always a wise decision. Using the technical expertise of a disinterested
third party will usually provide a more thorough and in-depth study
of your computer system.
Since there are so many issues to consider, jumping to the conclusion
that a bigger processor is needed may be a costly mistake. There
are many things to consider when a computer is experiencing degradation,
be it temporary or permanent. I could tell you about an A5F user
who moved to an A6K dual processor system with double the processor
and double the memory of the A5K and saw response time more than
double. That is, it did not decrease, but got much worse. Once you
spend the money, it is too late to go back. Performance analysis
is needed on all computer systems, but capacity planning is a pro-active
means to apply performance analysis to a business plan and make
decisions for the future when it will help most rather than making
a panic decision when one is pressured by the wrong people and possesses
Capacity planning should start with the installation of a computer.
First a base line is established. Then, performance information
is gathered regularly. How often data should be gathered is determined
by many site circumstances. One may gather performance data each
week or month, but at least once a month. A business plan must be
established and updated over time. An experienced performance analyst
can use the business data and performance data as well as a knowledge
of the applications running on your computer to make reasonable
estimates of when you will need to increase or upgrade components
of your computer system. There may come a time for a whole new replacement,
but usually needed resources can be updated to keep you operating
at a reasonable performance level with a proper weight of economical
Performance analysis requires software tools, programs, to gather
utilization data and then display it in useful graphs and reports
so that it may be analyzed. Most performance software, such as SMFII,
has never been accused of being user friendly. They are truly hard
to read and understand. Experienced performance analysts are required
to accurately interpret the data and make recommendations. It has
been my attempt to make useful utilization reports available in
my own performance software. My recommendation is that every site
should have performance software that creates easily understandable
reports for people with limited computer knowledge.
Given that you have user friendly performance software and you have
had a performance analyst perform a base line analysis for you;
next, you are ready to start your own weekly or monthly performance
monitoring. With the proper reports, you can watch your computer
grow and know what resources are growing most. As long as you are
not reaching a danger point (i.e. out of memory) condition you should
be able to monitor your own system. When you have questions or concerns,
you should have someone to call that you can rely on. Once every
six to twelve months you should have a performance specialist review
your data to verify that you are progressing properly. There may
be a need for some adjustments at these intervals.
The point is that you, the user, can control your own performance
analysis and use a specialist only when you have a need. You should
have a regular plan and compare your system growth with the plan.
Are you on course or do you need to make changes to accomplish your
goals. A specialist can make recommendations as to when you will
need to consider adding or upgrading resources so that you can make
the needed economical and operational plans.
You, the owner and user of the computer, should be in charge of
how you use your computer and where you are going with it. Don't
let the computer and its supposed needs dictate to you how and what
you are doing with it. There will be areas of expertise that you
will not have from time to time. Establish ahead of time who you
will use and trust in these areas. Use people resources when needed.
Don't let your computer operations control you. You take charge
of you computer installation and get help when you need it.
Modeling is another issue that is often used in performance analysis
and capacity planning. It is a way of taking your present and forecasted
workloads and having a modeling person or program recommend what
resources you need or will need. I have seen many forecasts by what
has been called the premier modeling program in the computer industry.
It has proved helpful on occasion.
Most performance analysts are in favor of using modeling programs.
This is an area where I disagree. It is a known fact that when the
best modeling program gives its best results it has a 25% error
factor. More often than not this error rate is much higher than
25%. It could be 50% or more. I believe that there are a few people
in the computer industry who can out-perform modeling programs.
I think that I can say without boasting that I have not made any
recommendations in forecasting that have come as high as a 25% error
factor. I know others who can do the same.
Most any technical person that Unisys has can do a "SMFII analysis"
and tell you that you need a bigger processor, maybe even the same
one that the salesman wants to sell you. My experience has been
that a "SMFII analysis" is rarely a true performance analysis.
A performance analysis is not geared to selling hardware, although
that may take place. It is directed at revealing the true measurement
of your computer system and giving steps to correct or improve the
situation. A capacity study or plan will further indicate a forecast
of where your computer and its resources are headed and compare
that with a business plan. Recommendations will then be made on
a planned course for a given period of time. Performance studies
should be made along the way to determine whether or not you are
following your business plan and where adjustments are needed.
The bottom line is that you, the computer user, can chart your own
future with your A Series computer. With a little help from a performance
specialist you can have confidence in your direction with computer
resources. With guidance and good software you can do most of the
work. You must understand how the A Series computer operates. A
brief presentation or seminar can give you the needed information
if you do not already have it.
I travel to different A Series sites I have observed different software
performance products. The PC monitors and graphical information
are really impressive. I was even present at a Teamquest presentation
of the new SMFII features. Unisys markets SMFII which is a product
from Teamquest. One of the better products that I have seen was
at a European site.
After seeing what others are producing over the last 20 years (I
first entered the performance arena in 1976), I wonder how much
of the software is written for show instead of analysis benefit.
What I mean by that is that the displays and graphs are attractive
to the senses, but functional analysis is needed for proper performance
analysis and capacity planning.
Over the past 10 to 15 years I have developed a product that I use
for my own purposes. I call it Utilization Software. It has evolved
as I see new needs for my analysis. It is certainly not as fancy
as most software on the market today, but it was not developed to
be marketed. It was developed as a tool to give the best analysis
that I think can be done.
Although Integrity Services now markets the utilization software,
it was developed with performance analysis in mind, not marketing.
This is probably the one thing that I have noticed with today's
performance software - it is written to impress the user rather
than do a complete job of performance analysis. Even where certain
reports are available, they must be configured; half-hour summaries
are impossible or hard to get. The best tools should be load and
go. The default reports should require very little if any adjustments
Now I realize that this is my view of performance analysis and performance
software tools and products; but it is my professional opinion.
A good performance tool is going to have critical information in
summary form at regular intervals that graphical representation
will not be able to properly portray. Examples would be disk queuing
and throughput rates (number of bytes/second and number of I/Os)
and mix reports at regular intervals sorted by resource use such
as CPU. I have found 30 minute intervals to be very effective in
On-line resource evaluation is also a valuable tool. When certain
resources are in use beyond specified thresholds the operator is
informed and steps may be taken to remedy the situation. If thresholds
are set properly then enough time will be allowed to adjust system
patterns before they adversely affect the system and its users.
An example would be that if you knew that a disk resource was exceeding
a threshold, you could attend to it before an out of disk situation
occurred. In the same way when processor or memory resources were
being used beyond a given threshold, then adjustment could be made
before a "thrashing" situation occurred.
NX and A Series Computers)
Setup is not required. Just load the files and start the job as
COPY = FROM UTILIZATION
START JOB/U (240)...where 240 minutes is the desired sample time.
The job may also be run under a usercode, if desired.
Of the following available reports, 1, 2, 3, 5, and 6 are listed
in the above job:
1. Summary information
2. Processor and I/O detail utilization statistics graph
3. Detail memory usage statistics graph
4. Unit queue detail report (For specified I/O units)
5. Subtotal summary information
6. Sorted mix report every [x] minutes
A selected time period may also be specified for the reports.
The first program is U/COLLECTOR. It gathers all the necessary information
and stores it in MEASUREMENTS, ENVIRONMENT, and UNITSTATS (Disk
files). The internal value supplied to collector is a time value
(in minutes) that it is to collect information (i.e. RUN U/COLLECTOR
("MIX 15"); VALUE=30 will run the program for 30 minutes).
A sorted mix will be produced every 15 minutes. Also, any accept
message will cause collector to go to EOT. The second program is
U/STATISTICS. It produces reports based on input specifications.
The following parameters are used at run time for U/STATISTICS:
Summary only (default)... Blank
Specify report times ............. RMT
Processor utilization.............. CPU
Memory usage ..................... MEM
Detailed unit queue report.... UR
Print a mix report.................. MIX ............ (The frequency
of the mix is specified to U/Collector)
Skip n samples (overview).... FREQ n
Subtotal every n samples...... SUBT n
Sort unit report by worst case WORST n... (n = number of units)
Print disk only in unit report.. DISK
A few examples should illustrate the use of parameters:
RUN U/STATISTICS("CPU MEM"): Processor, memory and summary
RUN U/STATISTICS("CPU RMT"): Processor and summary reports
for the specified time
period. (Times are entered remotely at a terminal)
RUN U/STATISTICS("MEM SUBT 30"): Memory, subtotals for
30 minutes, and summary
RUN U/STATISTICS("CPU FREQ 60"): Processor report every
Note 1: Subtotal and total reports include statistical reports showing
average use of processor in
eight different categories, IO rates and activities, ready queue
activity, memory usage, unit
queuing and IO rate separated into reads and writes, and system
Note 2: Unit numbers for detailed unit reports may be entered via
a job file or remotely depending
on the place of execution.
Executable program code and a JOB file with default settings are
Specify: 4.3 or 4.4 or 4.5 Release