This is probably a silly question but here goes anyway...

I have a dual cpu machine running winNT. When I run POVRay it seems to use
very little CPU time (as shown in TaskManager) usually about 2 to 5 percent.
Now, is this a misrepresentation from NT (Egads! Are you implying NT has
bugs?) or is POV not using all that it could?

Disclaimers...

1. I know POV doesn't support multi-CPUs, I'm not concerned about that right
now.

2. For those who don't know, in NT with 2 CPUs if a program is sitting in 1
CPU running full blast it will show 50% usage in TaskManager (which makes
sense to me).

3. Yep, I set POV to highest priority and nothing else is running that eats
many cycles.


This brings me to another question. What is the coorelation between the
priority setting in POV and the priority setting via the TaskManager?
Presumable when the render thread is created it takes over the priority as
set in POV and the TM priority applies to the GUI only. Yes?


Thanks,

--Rainer

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On Fri, 18 Sep 1998 16:17:28 +0900, Rainer Mager <rvm### [at] cyberadjp> wrote:
>This brings me to another question. What is the coorelation between the
>priority setting in POV and the priority setting via the TaskManager?
>Presumable when the render thread is created it takes over the priority as
>set in POV and the TM priority applies to the GUI only. Yes?

The priority setting in POV is the Thread priority.  This priority is an offset
between -2 and +2, specifying the relative priority of this thread within the
priority class of its containing process.  As you say, this priority setting
affects only the render thread.

The priority setting in Task Manager, however, is the process priority class.  
This affects the entire process and makes a bigger difference in general than 
does the Thread priority.  The priority difference between classes is 5, so a 
"lowest" priority thread in a "high" priority process still beats a "highest" 
priority thread in a "normal" priority process.  Since it does affect the entire
process, it affects both the GUI and the render thread, and any other threads
that might be running in the process.

There are some exceptions to these generalizations.  In particular, the 
"realtime" priority class is as big as all the other priority classes put 
together, and there is another thread priority, not available in the POV 
interface, that can cause a thread to run outside its priority class.

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