RE: 10046, Unaccounted for Time, Aix 5.3 -- How to Determine Process Pre-Emption

  • From: "Larry G. Elkins" <elkinsl@xxxxxxxxx>
  • To: <cary.millsap@xxxxxxxxxxxx>
  • Date: Wed, 2 Dec 2009 15:35:26 -0600

Profiler (and other similar products) are already used. Mrnl is not, though
it would most certainly be useful. Aggregated unaccounted for time is known.


 

What is being looked for by the "SA's" is something along the lines of
strace, truss, ptrace, trace, whatever, and how those could be used by the
SA's to see if pre-emption is occurring. They aren't sure of the best
way/tool to use, and I don't have a recommendation for them, though plenty
of examples, especially tied into Oracle, for flavors other than AiX.

 

Larry G. Elkins

 

Larry,

See pages 170-173 if you have access to a copy of Optimizing Oracle
Performance (O'Reilly). Bottom line: unaccounted-for time in trace data on
Oracle 9.2 or beyond is almost certainly time spent preempted.

Your analysis is sweet-spot for two of the software tools we make. Check out
these if you're interested:

*       Method R Profiler (http://method-r.com/software/profiler), which
reports on properly aggregated unaccounted-for time.
*       And mrnl (http://method-r.com/component/content/article/116) in the
MR Tools suite, which allows you to drill in on exactly which specific lines
of trace data are contributing the most unaccounted-for time. The final
example on the mrnl web page I pointed to at the beginning of this paragraph
is your situation on the nose.

Let me know if there's anything we can do for you...

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