Re: cpw. unconstrained vs constrained.

This is from
http://www.the400resource.com:2580/data/AMARCHIVE.NSF/504ca249c786e20f85256284006da7ab/14655375448e67658525676e0075afd1?OpenDocument

or use   http://makeashorterlink.com/?C1F6204B


Do you understand the unconstrained and constrained CPW ratings that now
accompany some smaller AS/400 models?
Yes: 10 percent
No: 90 percent
The vast majority of respondents reported that they did not understand the
unconstrained and constrained CPW ratings. Odell offers his perspective on
the subject:

Traditional AS/400 models have a single CPW value that represents the
maximum workload that can be applied to that model. This CPW value is
applicable when the commercial performance workload is applied to a fully
configured system. The resulting "CPW rating" is achieved when the correct
transaction mix of the benchmark is used and at least 90 percent of the
new-order transactions complete within five seconds. The maximum CPW rating
on most AS/400 models is gated by maximum CPU utilization, generally 90-95
percent; that is, other "system" resources, such as memory, disk arms,
cache, etc., are not limiting the performance of the "system" in the CPW
benchmark. However, in the smallest models of the AS/400e series, the
maximum memory or number of disk arms may become the performance gating
factor before the CPU utilization-in the CPW benchmark.

The "constraining factor" for the very demanding CPW benchmark on these
smaller systems is not the CPU utilization, but the limited memory or disk
configuration. Hence the CPW rating is artificially "constrained" by the
I/O allowed in the configuration. More memory or more disks in the future
would release the constrained performance.

The "unconstrained CPW rating" is the rating achieved when the CPU
utilization is the gating factor rather than the I/O disk or memory. For
workloads that do not perform as many disk operations or don't require as
much memory, the unconstrained CPW value may be used to estimate performance.

John Ross



At 11:50 AM 4/17/02 -0400, you wrote:


>What is the difference between constained and unconstrained cpw.    Will a
>batch job that is mostly cpu and memory bound, little io, run unconstrained
>?