Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support]

["J. Mayer" <l_indien@magic.fr>]

On Wed, 2007-09-19 at 16:35 +0100, Paul Brook wrote:
> > > >> OK, great. Having 64 bits may also help for additional (ie future...)
> > > >> features in PowerPC 64 emulation.
> > > >
> > > > Maybe worth letting the target say whether it needs 32 or 64-bit
> > > > flags.
> > > > The flag lookup is likely to be on a hot path.
> > > >
> >
> > I may be wrong, but it seems to me that TB flags are only used to be
> > compared in tb_find_fast and tb_find_slow, which are not a very fast
> > path (we come here when we cannot jump directly to the next tb and are
> > not in the most time critical code) then we can afford adding a few asm
> > instructions (I would say max 2 ?) to replace a 32 bits comparison with
> > a 64 bits one. My feeling is that the performance loss here won't be
> > sensible, but that may need to be proved.
> 
> For some reason I thought the flags were also used in the hash lookup. This is 
> not the case, so I withdraw my objection.

OK, then I feel like the flags size modification patch is acceptable.
If there is no objection (and if no one commits it before ;-)), I'm
ready to integrate it in the days to come.

-- 
J. Mayer <l_indien@magic.fr>
Never organized