[Qemu-devel] qemu-system-ppc speed

[Qemu-devel] qemu-system-ppc speed

[Brad Watson]

Hi All,

I've been experimenting w/running linux under
qemu-system-ppc.  My impression is that is
considerably slower than linux running under qemu. Is
it due to primarily endian conversion overhead or
something else ?

Regards,

Brad Watson


		
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Re: [Qemu-devel] qemu-system-ppc speed

[Natalia Portillo]

It is due to emulation overhead, and the PowerPC CPU (specially the MMU)
complexity.

> -----Mensaje original-----
> De: qemu-devel-bounces+iosglpgc=teleline.es@nongnu.org 
> [mailto:qemu-devel-bounces+iosglpgc=teleline.es@nongnu.org] 
> En nombre de Brad Watson
> Enviado el: sábado, 03 de julio de 2004 22:09
> Para: qemu-devel@nongnu.org
> Asunto: [Qemu-devel] qemu-system-ppc speed
> 
> Hi All,
> 
> I've been experimenting w/running linux under 
> qemu-system-ppc.  My impression is that is considerably 
> slower than linux running under qemu. Is it due to primarily 
> endian conversion overhead or something else ?
> 
> Regards,
> 
> Brad Watson
> 
> 
> 		
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Re: [Qemu-devel] qemu-system-ppc speed

[J. Mayer]

On Sat, 2004-07-03 at 23:14, Natalia Portillo wrote: 
> It is due to emulation overhead, and the PowerPC CPU (specially the MMU)
> complexity.

In my opinion, PPC is far less complicated than x86....
I ran nbench under qemu-system-ppc some time ago. It gave me the
emulated system was 15 times slower than the host machine. It seems to
be quite acceptable to me.

> > En nombre de Brad Watson
> > Hi All,
> > 
> > I've been experimenting w/running linux under 
> > qemu-system-ppc.  My impression is that is considerably 
> > slower than linux running under qemu. Is it due to primarily 
> > endian conversion overhead or something else ?

Did you compare with i386-softmmu ?


-- 

J. Mayer <l_indien@magic.fr>

Never organized

Re: [Qemu-devel] qemu-system-ppc speed

[Brad Watson]

Hi J,

I was comparing the ppc-softmmu w/ the i86-softmmu. 
I've since noticed the following messages in dmesg on
the ppc Linux instance, and I suspect that my
impression that it was more "sluggishness" is likely
related to the following messages:

hdc: DSC timeout
hdc: DSC timeout
.
.
.
etc.

hdc was assigned to an iso file via the  -cdrom
parameter when qemu-system-ppc was started.

Regards,

Brad Watson


--- "J. Mayer" <l_indien@magic.fr> wrote:
> On Sat, 2004-07-03 at 23:14, Natalia Portillo wrote:
> 
> > It is due to emulation overhead, and the PowerPC
> CPU (specially the MMU)
> > complexity.
> 
> In my opinion, PPC is far less complicated than
> x86....
> I ran nbench under qemu-system-ppc some time ago. It
> gave me the
> emulated system was 15 times slower than the host
> machine. It seems to
> be quite acceptable to me.
> 
> > > En nombre de Brad Watson
> > > Hi All,
> > > 
> > > I've been experimenting w/running linux under 
> > > qemu-system-ppc.  My impression is that is
> considerably 
> > > slower than linux running under qemu. Is it due
> to primarily 
> > > endian conversion overhead or something else ?
> 
> Did you compare with i386-softmmu ?
> 
> 
> -- 
> 
> J. Mayer <l_indien@magic.fr>
> 
> Never organized
> 
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
> 


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