Re: [PATCH] qemu does not have dcache aliases

[Geert Uytterhoeven <geert@linux-m68k.org>]

On Mon, 21 Aug 2006, Thiemo Seufer wrote:
> Ralf Baechle wrote:
> > On Mon, Aug 21, 2006 at 04:16:21PM +0100, Maciej W. Rozycki wrote:
> > 
> > > > Well, the QEMU cpu has 2-way 2kB dcache... does not have aliasing
> > > > anyway. :-)
> > > 
> > >  I don't think emulating a bigger cache so that we can add aliases should 
> > > be *that* difficult.  Adding aliases themselves might be a bit trickier, 
> > > but the gain would certainly justify the hassle, wouldn't it?
> > 
> > The cache lookup for every access would have serious impact on performance.
> > The question is, is it worth the price?  Would such patches be acceptable
> > by the upstream qemu maintainers?
> 
> Likely not, given that performance is the prime criterion there.

It depends. If you just want to run MIPS Linux, yes.
If you want to debug the kernel on a MIPS core with cache aliasing[*], no.

[*] Replace with whatever slow-to-emulate and hard-to-debug feature.

Gr{oetje,eeting}s,

                                                Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                                            -- Linus Torvalds