O'Brien, David W. (NIH/CIT) [C] wrote:
We are running Z/os 1.7. It recently came to my attention that VIO had been
implemented in such a way that temp datasets no matter how small ALWAYS went to
DASD. One of my predessesors used a storclas with Guaranteed Space. Anyway a
user asked to be able to use VIO so I turned it on. Today he comes back with
test results showing higher chargeback for CPU when using VIO. My question is -
How is this possible?
We are processing the same numbers of records and eliminating some physical I/O and the CPU usage is higher.
The total CPU for the job doubled. I would have thought that eliminating some
of the channel activity would have reduced CPU usage. Can someone explain this
to me?
VIO is CKD DASD emulated by software.
Some processing that would normally be "offloaded" to the DASD
controller is now being done by software running on general CPs, the
storage occupied by the emulated file will need to be paged in/out, etc.
Do you get better elapsed times?
--
Edward E Jaffe
Phoenix Software International, Inc
5200 W Century Blvd, Suite 800
Los Angeles, CA 90045
310-338-0400 x318
[EMAIL PROTECTED]
http://www.phoenixsoftware.com/
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