Re: [Qemu-devel] Qemu speed vs vmplayer?

[Joseph Miller]

Paul Brook wrote:
> > > If you're using an accelerator (eg. kqemu or kvm) this is all irelevant
> > > as most code isn't run by qemu, it's virtualized by the accelerator. qemu
> > > just does the IO emulation.
> > >
> > > Paul
> > >       
> > OK, so mmap is not the way to increase some speed.  What needs to be
> > done to provide a higher Qemu+KQEMU performance, comparable to
> > VMPlayer?  How does VMPlayer manage to be so much faster than Qemu?  Is
> > this simply an I/O bottleneck?  How would I go about finding out what
> > the differences are and how we can improve Qemu+KQEMU performance?
> >     
>
> A copy of the kqemu source would be a good start.
>
> Paul
>   
I've got a copy of today's CVS, I was just assuming, since this is the 
qemu-devel mailing list, that someone on the list who regularly works on 
the qemu code would probably know more about this than I do.  I have 
some assembly background, and I'm not afraid to start digging into x86 
cpu internals, but I would like a starting point.  I'm really trying to 
figure out something specific about qemu.  When running Qemu+KQEMU for 
linux-x86 host on WinXP x86 guest, top shows that 70% or more of my cpu 
is being use in the system portion.  When using vmplayer (free), top 
shows less than 5% of my cpu in the system portion.  vmplayer seems to 
be a LOT faster than Qemu, however I would prefer to use Qemu.  I have a 
P4 2.6GHz host system with 1.5G RAM and 512MB RAM allocated to my guest 
OS's.  Does anyone know the reason behind the slowdown?  Is anyone 
familiar with what Qemu is so busy doing whilst sitting idle?  I should 
note that I have compiled the KQemu into my 2.6 kernel instead of 
loading it as a module.  I have found better performance with it this 
way.  Any insight from a developer would be most appreciated.

-Joseph