[Simh] SimH vax.exe cpu usage on Windows.

[J. David Bryan]

On 18 May 2004 at 10:20, Bishop, Lewis wrote:

> ...i'm a bit concerned to see the cpu usage by vax.exe sitting at max
> (as much as it can get) and taking complete system cpu to 100%. 

That's a natural consequence of the simulated machine continually executing 
instructions.  In order for that to occur, the simulator itself must 
continually execute instructions, i.e., use 100%.


> ...does anyone know if there is a way to limit the CPU usage for
> vax.exe?

If you wish, you may decrease the running simulator's priority (from 
memory: press CTRL+SHIFT+ESC to bring up the Windows task manager, select 
the "Processes" tab, right-click on "vax.exe", and select "Set priority" 
from the popup menu).  But it's still going to use 100% of the CPU time 
remaining after higher-priority processes get their fill.

Also, as far as I know, Win2K slightly decreases the running priority of 
programs whose windows are not active, so if you want another program 
running concurrently with the simulator to have more CPU available, make it 
the active window.

(There'd be no real point to limiting the simulator artificially to, say, 
50% of the available CPU time.  The simulation would run half as fast for 
no gain, as the remainder would go into the PC's idle time.  There would be 
a point to having the simulator decrease its own priority, as an option, 
when the RUN command is given, but I don't know if there's a way that's 
portable across host systems to do that.)

                                      -- Dave