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

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

Date: 30 Jun 2005 06:29:53 -0700

Larry Kilgallen wrote:
> In article <1120105148.505681.16650@o13g2000cwo.googlegroups.com>, "AEF" <spamsink2001@yahoo.com> writes:
> >
> >
> > David B Sneddon - bigpond wrote:
>
> >> Does $GETJPI not operate within the context of the process
> >> you want the information about? In which case that process
> >> would need to "run" to return the information...
>
> Correct, for those items not available from non-paged pool.
>
> > I don't see how this can be. If $getjpi ran in the target process's
> > context, wouldn't its result go into a symbol in that target process
>
> No, $GETJPI knows nothing about "symbols" since they are DCL constructs.
> $GETJPI executes special kernel ASTs to get information from P1 space
> of other processes.
>
> > and screw it up? Also, if the target process needs to run $getjpi than
> > I'd expect to see processes all show up as CUR, since they are running
> > as you say.
>
> No, CUR is a process that has work to do and currently has a CPU devoted
> to it. All processes will show up as CUR only on a multiprocessor where
> there are as many CPUs as processes.

Thank you all for your helpful answers. But I have some further
questions:

This alls sound like subtle issues of timing and internals. Later I may
ask more specific questions to individual replies. Thank you all.

For now I ask: Why does SHOW SYSTEM work "properly" at priority 15
while WORKSET.COM doesn't? What's different about SHOW SYSTEM? SHOW
SYSTEM, when run at priority 15, doesn't show all processes in COM
states like WORKSET.COM does. My first guess would be that SHOW SYSTEM
uses $GETJPI and that WORKSET.COM uses F$GETJPI which uses $GETJPI (or
SYS$GETJPI?). So why the difference in behavior? I don't know, so I
ask.

Thanks again.

Relevant Pages

  • Re: [PATCH] sched: staircase deadline misc fixes
    ... + * This contains a bitmap for each dynamic priority level with empty slots ... Try two instances of chew.c at _differing_ nice levels on one cpu on mainline, ... cur = stamp; ... if (delta> thresh_ticks) { ...
    (Linux-Kernel)
  • Re: WORKING_SET.COM gives all COM states when run at high priority
    ... CUR is a process that has work to do and currently has a CPU devoted ... > ask more specific questions to individual replies. ... > SYSTEM, when run at priority 15, doesn't show all processes in COM ... absolutely needed but I suspect that is has common routines that it uses for ...
    (comp.os.vms)