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Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support]
From: |
J. Mayer |
Subject: |
Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support] |
Date: |
Wed, 19 Sep 2007 20:24:42 +0200 |
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 <address@hidden>
Never organized
- [Fwd: Re: [Qemu-devel] [PATCH] SVM support], J. Mayer, 2007/09/18
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], J. Mayer, 2007/09/18
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Paul Brook, 2007/09/18
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Alexander Graf, 2007/09/19
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Alexander Graf, 2007/09/19
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Jocelyn Mayer, 2007/09/19
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Alexander Graf, 2007/09/19
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Paul Brook, 2007/09/19
- Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support],
J. Mayer <=
Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Alexander Graf, 2007/09/19