On Fri, 5 Feb 2016 11:41:52 +1100, Andrew Rowley <[email protected]>
wrote:
>I am using JZOS to run Java as a batch job, and these are my tests for
>general processing of SMF data rather than time zone conversion
>specifically. It wouldn't surprise me if the batch job is better than
>running under the shell.
Tests I did a few years ago seemed to indicate that there was some additional
overhead from running under JZOS vs. BPXBAT*
Workload #1:
Average CPU secs (multiple runs)
zAAPn GCP
BPXBATCH 0.50 0.20
JZOS 0.73 0.12
BPXBATSL 0.52 0.14
I figured that maybe that was just a minor startup difference, but surprisingly
a much longer workload followed the same pattern:
Workload #2:
Average CPU secs (multiple runs)
zAAPn GCP
BPXBATCH 141.72 0.52
JZOS 153.49 0.39
BPXBATSL 142.09 0.45
But the JZOS launcher is more convenient, and unless you're very sensitive
about the consumed zAAP (now likely zIIP) time, the difference probably doesn't
matter.
This was under Java 6, but I don't recall what the exact processor model was.
My guess is that it was a z10 5xx.
Interestingly, IBM Java 7 seemed to add a little additional overhead. That was
somewhat expected for short-running tasks, but it seemed to be there for
long-running started tasks too, which was unexpected. It was in the single
digit percentage range, but it was consistent across multiple different
workloads. I never did get that difference understood to my satisfaction.
Scott Chapman
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