Re: WRKACTJOB?

Hi, Jeffrey:

OK, Jeff, move to the back of the class.  :^) 

Let's put this thing to bed.

Actually there *is* another way, and it is the way that IBM has chosen.
The system keeps track of CPU time used (in case the performance
monitor wants to grab that information, for example).  This is stored
in some detail within system areas of memory.  When WRKACTJOB is (first)
started, it retrieves the total CPU used to date, and stores it within
the PAG as the WRKACTJOB "stake in the ground" (or snapshot). Each
refresh of WRKACTJOB re-retrieves (from the same system areas) current
total snapshot informaton, and subtracts the saved snapshot values from
the newly-retrieved values.  Voila, you have "elapsed time" statistics
without having to keep a hidden process within the current job.

There is some truth to your logic.  It is this:
  There *is* always a process running which gathers those statistics.

However it is not correct to assume that that process is associated with
your current job.  Nor to assume that there is one for each instance of
WRKACTJOB.  There is exactly one process that gathers those statistics and
stores them in a reserved area.  All instances of WRKACTJOB share the
benefits of that same process.  Job accounting, performance monitoring,
WRSYSACT, WRKACTJOB, and those GUI tools that are available, all extract
information that is gathered automatically by the system.  This process is
an ever-active, cohesive part of the operating system.

Dennis




Jeffrey M. Carey <jeffreycarey@usa.net> on 26/09/97 20:36:17
To: MIDRANGE-L <MIDRANGE-L@midrange.com> @ INTERNET
cc:  
Subject: Re: WRKACTJOB?

No I don't think so, because the activity levels sure look like the
average over that time period - the only way it could do this is by
running in the background.  Try this to test it sometime - do a
WRKACTJOB.  F3.  Submit a batch job you know uses CPU.  Let it run for a
few minutes, then hold it.  Do another WRKACTJOB.  The batch job shows
non-zero CPU utilization - the only way that could happen is if
statistica are being captured from the time of the first WRKACTJOB,
since once the job is held,. it's CPU util. is 0.

I think this goes for WRKSYSSTS too.

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