[Bochs-developers] Porting WineLib on PPC, using Bochs for binaries

[Bryce Denney]

On Wed, 24 Apr 2002, KandY wrote:
> I'm currently very interested by porting some of the Wine tech.on PPC.
> I've been looking for people interested in this kind of painful duty but
> I didn't see anybody carrying this type of idea anywhere on the Web.
> I've already mailed some people on that subject and someone told me some
> people were trying to port WineLib on Sparc (Ulrich Weigand for
> instance...). Does anybody of you have more information on that ? Did
> somebody did that somewhere on the globe?
> 
> Besides that, to achieve my binary compatibility, I was looking at the
> Bochs emulation. Of course, I'm currently affected by some messages on
> the web saying the performances are not that great. I have nothing
> against emulation of machines but I only want to know of it is possible
> to port the Bochs on my Linux PPC and what performances can I expect
> (aren't there any benches to help me make my decision ?). Someone said
> that with a PIII 933, one can reach 3.5MIPS. Who can tell me success
> stories on that before I start working ?

That performance estimate sounds about right.  It's slow compared to
running on a real machine; there's no denying it.  In the wine port, you
would have the advantage that all the OS calls and graphics are running in
native code.  I don't have a good measure of how much time bochs spends on
graphics, polling for keyboard or mouse events, etc., but it would be
pretty easy to make that measurement if you run Bochs with no gui for a
while and test the instructions per second.

Usually people test the speed by compiling bochs with BX_SHOW_IPS set to
1.  Then every second it reports the number of instructions executed per
second, in the log file.

We frequently talk about ideas for performance improvements, but frankly I
think it will be a while (if ever) before we make even a 2x improvement.  
We do get some benefit from just waiting around, thanks to Moore's Law
applied to the machines that people typically run Bochs on. :)

Bochs has been focused on emulating entire systems, but it makes perfect
sense to used for a user-mode x86 binary emulation system as well.

-Bryce