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

[Andreas Davour]

On Tue, 18 May 2004, Mark Pizzolato wrote:

> Hi Lewis,
>
> I believe that you are worried about the 100% thing when you really
> don't have to.
[snip]
> Since your system is NOT a Notebook (which could benefit from
> dynamically turning down clock speed when the system is idle to
> reduce battery power consumption), running the CPU at 100% won't hurt
> anything.  It won't create more heat, or make your disks work harder,
> or anything.

I'm not sure it wont generate more heat when simh is idling at 100% CPU.
If it matter, that is another question.

> Andreas suggested that if you could figure out when the simulated
> system is "idle", you could get the simulator to idle itself as well.
>  As I've already said this is likely not worth the effort since there
> really is no net gain.

*shrug* You might be right. I know how to patch some PDP10 operating
systems for the PDP "idle" microcode, which decrease the CPU load
significantly. Maybe those patches are unneccesary, I don't know. I
haven't really looked at the simh source.

> All of that said, I've actually have a version of simh VAX which does
> support idling (or yielding) the CPU when the simulated system is
> idling.  The changes to support this affect several chinks of simh
> code.  I submitted it to Bob about a year and a half ago, and he
> didn't see the need.

I'd strongly suggest Bob to include your patch then. This "idle att 100
% CPU" is cropping up very often at newsgroups, chats and coffebreaks. I
see many users of simh looking worried when they see that busy CPU. It
might be pointless from a technocal perspective, but it sure would have a
direct psychological effect! .-)

/andreas