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Re: Understanding iSeries Performance Positioning



fixed

CPW benchmark is very close to TPC-C.
The major difference is that TPC-C requires independent auditing, and is a
very expensive undertaking.

I've had a chance before to mention that fast CPU does not guarantee good
commercial results - if I/O is a bottleneck, CPU will be mostly ilde.

    Alexei Pytel





                    "Nathan M. Andelin"
                    <nandelin@relational       To:     <MIDRANGE-L@midrange.com>
                    -data.com>                 cc:
                    Sent by:                   Subject:     Understanding 
iSeries Performance
                    midrange-l-admin@mid        Positioning
                    range.com


                    09/07/2001 11:31 AM
                    Please respond to
                    midrange-l





Hi gang,

I'd like to gain a better understanding of the benchmarks that IBM uses to
calculate the relative CPW ratings of their boxes.  I found some
information
by searching IBM's Web site.  But it's not much.  The information kind of
echoed the name of the benchmark - Commercial Processing Workload.  I
understand the benchmarks are sort of a melding of CPU, DB I/O, and
Communications, etc., rolled into one.

I found that other public benchmarks offer more detail.  You can even find
source code for some of the programs.

Some months ago, some of the list members, including me, ran a CPU bound
benchmark on our machines to compare CPU speeds alone.  We found, for
example, that the CPU speed of a 170-2385 was about 11 times greater than a
170-2290, and the CPU speed of a 270-2250 was about 17 greater.

That was interesting.  For one thing, the CPW rating of the 170-2385 is
about 6 times greater than the 170-2290, and the CPW rating of the 270-2250
is about 5 times greater.  I had previously supposed that CPU speed and CPW
rating would have been more closely correlated on the single CPU boxes.
Our
private benchmark quickly dispelled that erroneous assumption.

Does anyone know the makeup of the benchmarks used to calculate CPW rating?

Thanks,

Nathan.


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