On Wed, 19 Sep 2007 07:36:48 -0500, Tom Grieve
<[EMAIL PROTECTED]> wrote:
>Gary,
>
>For the JVM to be using that much CPU just for a simple HelloWorld, I'd
>guess you have an unsuitable LE STACK option. The JVM is an
XPLinked system,
>and so uses a downward-growing stack. LE detects when the stack
should be
>extended because a 0C4 results from trying to save registers in the
guard
>page. This is a pretty big overhead when it happens frequently.
Check your
>LE STACK runtime option. CICS recommends
>
>STACK(128K,128K,ANY,KEEP,128K,128K)
>
>You will also probably want to investigate heap usage. Running with
>
>RPTSTG(ON)
>
>will provide you with storage usage reports when the JVM
terminates. (Don't
>run with this on in production, though)
>
>Tom Grieve
>CICS Development
>IBM Hursley Park
>
>
>On Mon, 17 Sep 2007 11:00:59 -0400, Gary Green
<[EMAIL PROTECTED]>
>wrote:
>
>>Does anyone have any tuning/performance references/links for Java
under z/OS?
>>
>>Some tentative footsteps were taken to develop Java apps to run
under USS
>and the "Hello World" app sucked down 30% of the CPU during the
time the app
>was running. :( So, I gotta prepare for the onslaught when things
really
>kick into high gear.
>>
>>Thanks.
If you want to run that from the shell, you can do a:
export _CEE_RUNOPTS="RPTSTG(ON),RPTOPTS(ON)"
before you run your java command, and that will vomit out all the
goodies for you, although I really *hope* this is not your problem.
Aaron
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