Re: How are CPU Speed and Overall CPW Related?

As much as I want this thread to die...

Nathan, your concern is valid.  Don't buy the apples and oranges, (or it's
various permutations) argument.  Perception is 99% of reality.  (My former
boss was fond of quoting John Lennon).  If it's slower on your 400 than
your PC then it IS slower on your 400 than your PC.  That is black and
white.  Yes, absolutes do still exist.  There are a couple of ways that IBM
constrains the system, some you can work around.  Some of their hardware
and software constraints limit the processor for all activities, these are
tough to work around.  Some limit the processor for 5250 work - (I hope you
ran your test in batch).  And for the DSD, or bumblebee servers, just about
everything except for Domino is limited.  Some may argue that 'but the 400
shines with REAL work'.  This string manipulation IS real work.  I severely
restricted a subprocedure in a service program because using a generic huge
string made the results run a VERY noticeable length longer.  Years ago we
moved EDI to a seperate 400 because of the string manipulation's whacking
of performance, (and left it there because of tier pricing).

Rob Berendt

==================
Remember the Cole!


                                                                                
                                         
                    "Nathan M. Andelin"                                         
                                         
                    <nathanma@haaga.com        To:     
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                    Sent by:                   Subject:     Re: How are CPU 
Speed and Overall CPW Related?               
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                    05/04/01 11:05 AM                                           
                                         
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Let me give you some background, James.  I've been writing a lot RPG code
this past year - building a Web development framework.  And researching
whether a Web framework is a suitable alternative to 5250.

To help me optimize my RPG code, I'll sometimes write an equivalent in
Foxpro or Delphi and compare the difference.  It has puzzled me that my
$1,600 Laptop consistently out performs my $16,000 AS/400 - sometimes by a
factor of 10.  It further confused me after I learned that the AS/400 had a
200 Mhz processor - which I consider fast.  I wondered whether something
was
constraining the AS/400 processor.  I have now learned that IBM has some
means of governing the CPU so that I can only get at about 20% of it's
capacity.  PC manufacturers don't do that.  The puzzle is solved.

Your explanation of the I/O support provided to 5250 applications may lead
someone to conclude that the AS/400 is not built to handle Web
applications.
Perhaps, that's partly right.  I believe OS/400 is ideal for the Web.  But
a
constrained CPU is not.  Web applications require lots of CPU because they
involve the handling of lengthy streams.  Apparently IBM is beginning to
realize that - the capacity of their new servers is a step in the right
direction.

Nathan.



> Date: Thu, 03 May 2001 14:14:15 -0700
> From: "James W. Kilgore" <eMail@James-W-Kilgore.com>
> Subject: Re: How are CPU Speed and Overall CPW Related?
>
> Nathan,
>
> As everyone has been trying to tell you, you are comparing apples to
> oranges by this measure.
>
> It does bring up the point that no single machine is best suited to
> solve all problems.
>
> It wouldn't take much to bring your 100mhz PC to it's knees with some
> other task running at the same time.  The AS/400 is not intended to be a
> single function machine, so it is not optimized for those types of
> functions.  And, yes, it will measure poorly when tested for something
> it was not designed for.  As any machine would test poorly for something
> it was not designed for.
>
> I'm not sure what you are trying to get at, but you must face that
> reality that the AS/400 is -not- the best machine at all things, But, it
> is the best machine when a single machine has to do all things all at
> once.
>
> Although I liked the motorcycle vs bus example, I'll give you a
> different one that actually relates to computers and the AS/400 in
> particular.  This has to do with the response degradation curve.  That
> is, under other systems, there is a direct, linear curve that
> corresponds with the number of users and their response time.  The more
> users, the slower the response time.
>
> IBM created an I/O subsystem that flattened that curve.  A single user
> was faster on the other system when compared to the AS/400, but 20+
> users were slower.  (The same was true in token ring vs ethernet)  Now
> why would IBM do this?  Well, from what I've read, IBM spends a whole
> bunch of money on researching things like psychological factors in user
> satisfaction.  What they found was that any given user was happier (more
> satisfied) with a system that provided a consistent response time than a
> system that went from fast, to slow, then back to fast again throughout
> the work day.  So if you get .5 sec response time as a single user, you
> will still get .5 sec response time with 20 or 100 or 10,000 users.
> (provided that you have the right model for the workload)
>
> I guess the point that I'm getting to is that the AS/400 never was, and
> never will be, optimized for a single user.  It is designed to be a
> multi user, multi tasking, consistent response time, back room, boring
> fixture.
>
> "Nathan M. Andelin" wrote:


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