Re: WORKING_SET.COM gives all COM states when run at high priority

From: AEF (spamsink2001_at_yahoo.com)
Date: 06/30/05 

Date: 29 Jun 2005 19:34:08 -0700

Jeff Cameron wrote:
> On 6/29/05 4:33 PM, in article
> 1120087981.900047.325720@f14g2000cwb.googlegroups.com, "AEF"
> <spamsink2001@yahoo.com> wrote:
>
> >
> > Hello,
> >
> > WORKING_SET.COM, which is in SYS$EXAMPLES, lists all processes and
> > various working set statistics for each. I recently found out that when
> > you run it at high priority, most or all of the states show up as COM.
> > The state is determined by the function
> >
> > f$getjpi("","STATE")
> >
> > The higher the priority, the higher the percentage of states which are
> > reported as COM.
> >
> > Why should the result of this function be dependent on the priority at
> > which it is run?
> >
> > (Tested on VMS v6.1 and v6.2, both on VAX systems.)
> >
> > (On some systems it may be called WORKSET.COM.)
> >
> > Thanks.
> >
> This is because you arte at a high priority and when ever you are executing
> the function f$getjpi, you will always be at the CUR or current state, that
> is the one process on the system that has the CPU above all others, so
> anyone else that wants the CPU at that time will show up as COM or
> computable. You are preempting all lower processes that want the CPU.
>
> Jeff

Well, talk about the act of measuring affecting the measurement!

If my running workset.com is compute bound, and all other processes
want the CPU, then that makes sense. But there are many processes that
are just sitting there doing nothing. For example, I have several other
terminal sessions only and there are all inactive. At priority 15
pretty much ALL processes go into the COM state as reported by
workset.com.

I'll do some more experimentation later. Thanks for your rapid response!

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