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Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support]
From: |
Jocelyn Mayer |
Subject: |
Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support] |
Date: |
Wed, 19 Sep 2007 16:39:30 +0200 |
On Wed, 2007-09-19 at 12:56 +0200, Alexander Graf wrote:
> On Sep 19, 2007, at 1:28 AM, Paul Brook wrote:
>
> >>>> Ok, I will try to shift the intercepts in an uint_64 flags variable
> >>>> in the TB.
> >>
> >> 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.
> >
> > Paul
>
> here comes the patch.
The patch looks correct to me, I'm just wondering why a cast to 32 bits
is needed in mips code ?
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.
- [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 <=
- 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, 2007/09/19
Re: [Fwd: Re: [Qemu-devel] [PATCH] SVM support], Alexander Graf, 2007/09/19