Re: Perfromance issues

We suffered the same issue under different circumstances, and it was the
Performance Adjuster (system value QPFRADJ). See if it is set to 2 or 3,
which cause the performance of different subsystems to vary in relation of
system load.

Regards



2014-05-15 7:13 GMT+02:00 Imad Moukaddam <Imad-Moukaddam@xxxxxxxxx>:

Hi

We are encountering a very strange behavior in iSeries response time and
we are running out of possible causes to this phenomenon:
we developed a JAVA application that launches COBOL services on the
iSeries, via a Socket. Everything seemed to run smoothly.
Then we've tried to test the overall performance of the application,
therefore, we have used a test tool to simulate hundreds of simultaneous
connections, and this is where the strange behavior is being noticed: at
first everything seems to be alright, excellent response time from the
service on the iSeries machine, the CPU was running at around 85-90%, then
suddenly at a certain point, the response time from the service was more
than 10 seconds, and after that point, the response time were very awkward,
the same service gave very quick responses for some connection, and very
slow responses for other connections. More strangely, we've noticed that
when this behavior is occurring, the CPU utilization decreased to less that
50 or 40%... (meaning, while we are encountering performance issues, the
iSeries CPU is resting!)

It is like the requests were not getting through to the service!
Is there any explanation to this?
Hardware fault? (memory, disk...)
Too much QZSDAOINIT open?

We have tried to identify any possible lock on the database, but nothing
appeared to be faulty at this level neither.

Any help would be appreciated



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