Slowing down MSDOS

[venca]

Hi!
I was wondering, could anybody help me with this: I've installed MSDOS 6.22 on QEMU, but every time I run it it consumes 100% of CPU and that makes me quite nervous. I have read that DOS tends to do this as it doesn't use the CPU HLT instruction (whatever that means :") ) and that it could be fixed by DOSIDLE.EXE. I dowloaded this program and it really worked - as long as I stayed in the prompt :-/ As soon as I ran Dos Navigator or any game the CPU usage skyrocketed back to 100%
The same problem arised when using W9x under QEMU. I used the anmhlt.reg (as it is written in the QEMU user guide) and again it was okay while I stayed in Windows but when I ran any of the previously mentioned programs -> 100% CPU

Could this be fixed somehow? And if not, is there any risk it will damage my CPU? Because I'm getting pretty nervous listening to my CPU fan spinning all the time

I have a P4 2,8GHz if it matters in any way...

[zezinho]

This is normal, as when those programs you run were done, no one thought about energy saving. The partial solution I've found on my Linux box is to use a cpu frequency daemon like powernowd or cpufreqd configured to keep to processor at a slow speed while running niced tasks. Then launch qemu niced. So my Pentium-M 1733 runs only at 800MHz, keeping it cooler.

There is a patch for kernel 2.4 that allow to force a process to only use a percentage of the cpu, but nothing for 2.6.

The nice thing would be to add a parameter to qemu to only allow it to use n of the CPU.

[lyfoc]

I run dosidle.exe under FreeDos 9.0 and find the cpu down to 3~4%, that's nice!
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[nemti]

I saw this on another thread for Windows 3.1, I'm not sure if it would work in this situation.

EDIT:
Actually, upon further inspection, this appears to be windows specific, sorry.

[miraz]

Hi,
I've made a patch Qemu Brake which slows down the Qemu and saves CPU usage. It is suitable mainly for DOS emulation.
It is available at http://miroslavnovak.com/qemu-brake.html including a ready to run sample for Linux and Windows. The sample contains an old dos game installed, which demostrates the capability od the Brake patch. Please try it.