Date   : Wed, 17 Aug 2005 22:24:36 +0100
From   : Joe N <ng22311@...>
Subject: Re: BeebEm bug?

Thanks for your advice Tom. I can see your point about it using clock 
cycles that don't apparently don't do anything, but don't you think that 
running a 1.8 Gig P4 at 99% is taking the piss a bit? :-) The thing I 
can't quite get my head around is that, although it is using 99%CPU and 
overheating my chip, it doesn't have an adverse effect on any other 
running app. It apears that the scheduler is quite happy to let it go 
flat out but happily swap it out for anything else that wants a 
timeslice. It just doesn't seem to add up. Usually when I've got a flat 
out process like that it chokes the whole system.

Apologies, this is no place to be talking about Windows (spit, spit!) 
scheduling but it has got me rather intrigued...

Also, if anyone's interested, I have downloaded BeebEm 2.2 and it is NOT 
displaying the same symptoms. We're down to about 7-10% processor usage 
so I think it may be something not quite right with the version I was 
using previously.

Back to Repton 3...

Regards,
Joe.

>
> Probably not, that's just how these things work -- it's the same with 
> games, and with other emulators. Most programs can sit there doing 
> nothing whilst waiting for Windows to tell them there's some input, 
> and this doesn't count as CPU usage. (I believe Windows in effect 
> switches the CPU off for very brief periods of time when all programs 
> are waiting for input -- which is most of the time, usually -- so it 
> genuinely does count as not using the CPU.)
>
> But in the case of emulators, there isn't such a point -- even when 
> the emulated computer appears to be idle, it is in fact still running 
> instructions, just instructions that don't do anything apparent. So, 
> the emulator has to keep running, and you get 100% CPU usage. (This is 
> the same even in 'actual speed' mode; the emulator still has to run 
> all the time, but spending lots of its time running a small delay loop 
> that does nothing.)
>
> --Tom
>
> P.S. I don't have any affiliation with quietpc.co.uk, but I got from 
> them a good -- and quiet! Very quiet! -- fan for my PC (pentium III), 
> so they may be worth looking at if you need a new one.
>
>
>