Re: [PATCH] qemu does not have dcache aliases

[Thiemo Seufer <ths@networkno.de>]

Geert Uytterhoeven wrote:
> 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.

I wrote about qemu upstream's priorities.


Thiemo