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Re: [Qemu-devel] Profiling Qemu for speed?
From: |
Christian MICHON |
Subject: |
Re: [Qemu-devel] Profiling Qemu for speed? |
Date: |
Mon, 18 Apr 2005 16:12:05 +0200 |
I did months ago gcc/FDO with a xp/lite installation as a "repetitive task" :)
I did not improve the timings after all the effort.
Christian
On 4/18/05, Daniel Egger <address@hidden> wrote:
> On 18.04.2005, at 11:51, Ian Rogers wrote:
>
> > I'm not sure if you can get GCC to generate code sequences like this,
> > but you probably at least need to use the -fprofile-generate and
> > -fprofile-use options
> > http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
>
> Feedback optimisation (FDO) will not work for two reasons:
> a) qemu itself is something like a realtime compiler so FDO
> will only speed up the compiler but not the generated code
> b) FDO will only provide speed boosts if the feedback phase
> has a chance to analyse a representative work pattern that
> is hopefully also repetitive
>
> After all FDO is mostly about making a tradeoff size/speed
> and rearranging code (mostly branches) to avoid branch
> mispredictions of the CPU.
>
> Servus,
> Daniel
>
>
> _______________________________________________
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> address@hidden
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>
>
>
>
--
Christian
- Re: [Qemu-devel] Profiling Qemu for speed?, (continued)
- Re: [Qemu-devel] Profiling Qemu for speed?, Paul Brook, 2005/04/17
- Re: [Qemu-devel] Profiling Qemu for speed?, Jonas Maebe, 2005/04/17
- Re: [Qemu-devel] Profiling Qemu for speed?, Nathaniel G H, 2005/04/17
- Re: [Qemu-devel] Profiling Qemu for speed?, John R. Hogerhuis, 2005/04/17
- Re: [Qemu-devel] Profiling Qemu for speed?, André Braga, 2005/04/17
- Re: [Qemu-devel] Profiling Qemu for speed?, Karl Magdsick, 2005/04/18
Re: [Qemu-devel] Profiling Qemu for speed?, Paul Brook, 2005/04/17
Re: [Qemu-devel] Profiling Qemu for speed?, Daniel J Guinan, 2005/04/18
Re: [Qemu-devel] Profiling Qemu for speed?, Daniel J Guinan, 2005/04/18