Re: Are compression services (CMPSERVS) eligible for zIIP/zAAP execution?

-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@xxxxxxxxxxx] On
Behalf Of Russell Witt
Sent: Wednesday, September 09, 2009 11:32 PM
To: IBM-MAIN@xxxxxxxxxxx
Subject: Re: Are compression services (CMPSERVS) eligible for
zIIP/zAAP
execution?

Peter,

Just because a service can be eligible for a zIIP does not mean it
will be
offloaded to one if you obtain a zIIP processor. There are the
environmental restrictions. The eligible workload must be run in an
SRB
enclave that is identified as being zIIP eligible. If the batch job
that
is doing a lot compression is a home-grown utility, you may have a
hard
time getting it zIIP eligible. If the batch job is executing a Strobe
utility, then you will need to check with the Strobe people to find
out if
they have made it zIIP eligible or not.

I guess I did not make the situation clear enough. This application
does not directly use compression calls, but the sequential and VSAM
files that it reads and writes have an assigned DATACLAS that puts them
in Extended, Compressed SMS pools. So the compression and decompression
are being done by the operating system, not by the application.

CMPSERVS is the portion of the operating system that is performing these
functions on behalf of the application. I see these routines named in
the Strobe performance report. They are not part of Strobe, they are
part of the operating system. For this application, as measured by
Strobe, they are consuming 52% of the used CPU time.

So, my question is, are the operating system compression/decompression
routines eligible for zIIP/zAAP execution, if such engines are
available?

Peter


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