Date:         Wed, 10 Feb 1999 11:01:19 -0500
Reply-To:     "Konkler, Dan" <DKonkler@NT.DMA.STATE.MA.US>
Sender:       "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From:         "Konkler, Dan" <DKonkler@NT.DMA.STATE.MA.US>
Subject:      Re: (MVS) PEEK and PEEKC to get at CPU time
Content-Type: text/plain

Peek and Peekc only read a value that is in an MVS control block.  If the
task that is
looking at the value never loses control of the cpu i.e. is never
interrupted, then I don't see how the value can be updated.
It is theoretically possible to have a job that uses thousands of cpu
seconds which are never reflected in
the control block until the system regains control at the end of the task.
Usually MVS switches tasks thousands of times per second but with multiple
processors your task might still go uninterrupted.  I am fairly certain this
happens because
I have called peekc and sometimes it deosn't change.  the timer unit goes to
about a billionth of a second so I believe that
almost any instruction (like AR add register) should cause an increment.
The bottom line is that looking at this field
will vary and it ends up being approximate only.