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Re: [Qemu-devel] [PATCH 1/7] alpha: Implement IMB; add placeholders for
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH 1/7] alpha: Implement IMB; add placeholders for other userspace PALcalls. |
Date: |
Sun, 13 Dec 2009 21:47:49 +0100 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Sun, Dec 13, 2009 at 11:54:02AM -0800, Richard Henderson wrote:
> On 12/13/2009 11:28 AM, Aurelien Jarno wrote:
> >Is it really necessary to flush all the TB here? QEMU should already
> >discard TB that have been modified.
>
> No. But I meant to look into this more carefully with a view to
> disabling the other checking within QEMU and speed things up a tad.
> It seems to me that the explicit checking with each memory write
> ought to only be necessary on architectures like x86 that don't
> architecturally require a flush insn to be used.
This is actually done only on the first write access to a page and not
to each write, so it should not be so costly. It is however something
to investigate, as I agree that removing the checks can add some
speed-up.
> I can drop this fragment if necessary for patch acceptance, however.
>
I think it is better to drop it until we have a better view of the whole
thing. You can add a comment saying that an optimisation might be
possible here.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
- [Qemu-devel] [PATCH 0/7] Improve alpha-linux userspace emulation, Richard Henderson, 2009/12/09
- [Qemu-devel] [PATCH 7/7] alpha: Fixes for alpha-linux syscalls., Richard Henderson, 2009/12/09
- [Qemu-devel] [PATCH 4/7] alpha: Remove bogus DO_TB_FLUSH code from translator., Richard Henderson, 2009/12/09
- [Qemu-devel] [PATCH 5/7] alpha: Honor the -cpu command line argument., Richard Henderson, 2009/12/09
- [Qemu-devel] [PATCH 3/7] alpha: Add binfmt entry., Richard Henderson, 2009/12/09
- [Qemu-devel] [PATCH 2/7] alpha: Drop bogus UNIQ initial value on Linux., Richard Henderson, 2009/12/09
- [Qemu-devel] [PATCH 6/7] alpha: Enable softfloat., Richard Henderson, 2009/12/09
- Re: [Qemu-devel] [PATCH 0/7] Improve alpha-linux userspace emulation, Laurent Desnogues, 2009/12/10
- Re: [Qemu-devel] [PATCH 0/7] Improve alpha-linux userspace emulation, Tristan Gingold, 2009/12/11