Re: [Qemu-devel] Qemu workstation

[Brad Campbell <brad@wasp.net.au>]

Richard Zidlicky wrote:
> On Mon, Apr 05, 2004 at 10:49:51PM +0100, Jamie Burns wrote:
> 
>>>I am not sure that handling multiple VMs running at the same time is
>>>very useful (some architectural changes are needed in QEMU). But
>>>switching easily between VM configurations seems interesting.
>>
>>I think that multiple VM's is a worthy goal as long as you can minimise CPU
>>usage. Having multiple VM's gives you the ability to do some very cool
>>things. I use VMWARE in Windows and sometimes have both Linux and FreeBSD
>>running in VM's so I can test software against all 3 OS's at once. I imagine
>>it would be very useful to developers of cluster software.
>>
>>I tried the Win32 port the other day, running Linux, and it sat using 100%
>>of the CPU whilst doing next to nothing at a command prompt. Using VMWARE,
>>and waiting at a command prompt uses very little CPU time.
>>
>>Is QEMU sat in a busy loop all the time?
> 
> 
> it is not QEMU but the hosted OS that is in the busy loop. QEMU
> will have to recognise "idle loops" to fix this - this could be
> really tricky.

I guess if QEMU emulates the hlt instruction and the OS supports it then it's pretty easy.
I note above it said running linux, which does idle nicely when the hlt instruction is present, 
perhaps there is a not too difficult way for intelligent OS's. DOS is a lost cause however.

Brad