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CPU time is snowballing - possible causes?

 
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nuck

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PostPosted: Mon Aug 20, 2007 2:38 pm    Post subject: CPU time is snowballing - possible causes?
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hi fellow listies,

I've got an exec that is exhibiting some rather odd behaviors (not entirely unlike the programmer that wrote it icon_confused.gif ).

The CPU times that it takes to run through the main loop keeps getting longer and longer. For example, if I run it with a loop of 'do j=1 to 100' the first ten iterations are relatively quick (under 1 second CPU), after the 10th loop it's up to over 10 seconds, after the 20th, it's ove 30 seconds per 'do j'. I ttested this by changing the loop condition to 'do j=30 to 35', and these iterations run just as quickly as the iterations 1 thru 5 in the first test. huh???
Seems to indicate that something is stealing storage somewhere, not letting it go, and slowing everything down.
Any ideas what it could be?

thanx in advance!
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ofer71

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PostPosted: Mon Aug 20, 2007 3:02 pm    Post subject:
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Can you post the entire loop?

O.
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nuck

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PostPosted: Mon Aug 20, 2007 3:56 pm    Post subject: Reply to: CPU time is snowballing - possible causes?
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ummmm...not really...

well, I could, but it's about 600 rows of code...I'm currently checking if it's caused by compound vars not getting re-initialized - altho that shouldn't really be causing this much trouble (?)

I suspect it's from a sort that I call (ICEMAN) where I'm reallocation the sysin, sysout, etc every time thru. That would slow it down a bit, but so much?

I'm gonna put in some tracing infos that track the cpu usage at various points in the prog, that should help me narrow it down.

I wasn't really looking for the exact solution to this prob - more of a 'what could it be?' question. I haven't had something like happen in Rexx yet, and I've been playing with rexx for damn near 20 years.
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ofer71

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PostPosted: Mon Aug 20, 2007 4:52 pm    Post subject:
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How about QUEUEs? Any ISPF services? ISPF table manipulation?

O.
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nuck

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PostPosted: Mon Aug 20, 2007 5:14 pm    Post subject:
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oops icon_redface.gif looks like another classic of case PEBCAK.... icon_eek.gif

I jumped the gun on this one - turns out I should've finished my testing...there is a problem with my initializations, which means my compound vars are just getting bigger and bigger and bigger - which would also explain the snowballing effect on cpu time. icon_redface.gif

sorry guys, my fault. Back to the drawing board.

Indian-Delta-10-Tango....(referring to myself)
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dick scherrer

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PostPosted: Mon Aug 20, 2007 9:45 pm    Post subject:
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Ahhhh. . . another instance of the I-D-ten-T error icon_smile.gif

I hate when i raise those icon_wink.gif

But just who is PEBCAK - as in "another classic of case PEBCAK"?
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dbzTHEdinosauer

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PostPosted: Mon Aug 20, 2007 10:31 pm    Post subject:
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I must be an I D 1 0 T, but I don't under stand I-D-ten_T error.

I hate it when I am one.

Like the way I am feeling now, trying to figure out PEBCAK....
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dick scherrer

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PostPosted: Mon Aug 20, 2007 11:19 pm    Post subject:
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Quote:
an I D 1 0 T, but I don't under stand I-D-ten_T error

Hmmm . . . from the quote, but phonetically . . eye dee one zero tee . . ID10T (or id-ten-t) icon_smile.gif
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nuck

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PostPosted: Tue Aug 21, 2007 11:48 am    Post subject:
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heh...

PEBCAK= Problem Exists Between Chair And Keyboard.

phonetically I used the NATO alphabet (alpha, bravo, charlie, etc) for the Indian Delta ten Tango.

I love it when someone asks me to spell out my last name - I do it phonetically, which is kinda long, cuz my last name is 13 characters long. Usually after the fifth character they're yelling at me to stop.
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agkshirsagar

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PostPosted: Tue Aug 21, 2007 2:16 pm    Post subject:
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Shouldn't this topic be moved to Fun stuff???? icon_wink.gif icon_razz.gif
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nuck

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PostPosted: Tue Aug 21, 2007 2:19 pm    Post subject:
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PS: solved the bug in my exec. Now it takes about 10 CPU minutes from start to end to analyze 280 JCLs, including the building of cross-references and dependencies. YAAAY!!!!
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dick scherrer

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PostPosted: Tue Aug 21, 2007 10:20 pm    Post subject:
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Good to hear that the exec now runs successfully icon_smile.gif

Ten minutes cpu time still sounds like a lot. . . That comes to just over 2 cpu seconds per jcl. Even fixed, it sounds like an intense exec.
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nuck

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PostPosted: Wed Aug 22, 2007 11:05 am    Post subject:
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yup, most of the JCLs take less than 2 seconds, the JCLs with 50 steps tend to chew up a lot of cpu time.

my exec creates documentation for the operations boys, a listing per job and step of which files are used, with a cross reference for each DSN to all other jobs (we can then see where the dsn is created), as well as the scheduling dependencies.

so, it does have a fair bit of processing to do.

...and before the flaming starts: Yes I know docu is usually created BEFORE a program or JCL is written. However, this method guarantees that the docu matches EXACTLY to the code. And it removes the possibility of human error while writing said docu.

PS: I'd love to find a job where I write more REXX stuff....it's just too much fun.
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