Re: [REPORT] [GSoC - TCG Continuous Benchmarking] [#2] Dissecting QEMU Into Three Main Parts

[Lukáš Doktor]

> However, we know that the results for hosts of different architectures
> will be different - we expect that.
> 
> 32-bit Intel host will also most likely produce significantly
> different results than 64-bit Intel hosts. By the way, 64-bit targets
> in QEMU linux-user mode are not supported on 32-bit hosts (although
> nothing stops the user to start corresponding instances of QEMU on a
> 32-bit host, but the results are unpredictable.
> 
> Let's focus now on Intel 64-bit hosts only. Richard, can you perhaps
> enlighten us on whether QEMU (from the point of view of TCG target)
> behaves differently on different Intel 64-bit hosts, and to what
> degree?
> 
> I currently work remotely, but once I am be physically at my office I
> will have a variety of hosts at the company, and would be happy to do
> the comparison between them, wrt what you presented in Report 2.
> 
> In conclusion, I think a basic description of your test bed is missing
> in your reports. And, for final reports (which we call "nightly
> reports") a detailed system description, as Mr Lukas outlined, is,
> also in my opinion, necessary.
> 
> Thanks, Mr. Lukas, for bringing this to our attention!
> 

You're welcome. I'm more on the python side, but as far as I know different cpu 
models (provided their features are enabled) and especially architectures 
result in way different code-paths. Imagine an old processor without vector 
instructions compare to newer ones that can process multiple instructions at 
once.

As for the reports, I don't think that at this point it would be necessary to 
focus on anything besides a single cpu model (x86_64 Intel) as there are 
already many variables. Later someone can follow-up with a cross-arch 
comparison, if necessary.

Regards,
Lukáš

> Yours,
> Aleksandar
> 
> 
> 
> 
>> Best regards,
>> Ahmed Karaman
>

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