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Re: cortex / arm-hardfloat-linux-gnueabi (was Re: armelfp: new architecture name for an armel variant)

On Friday 16 July 2010 07:58:02 Paul Brook wrote:
> Mainly that your analysis of the code was almost entirely bogus.

You are free of course to take my analysis any way you like -btw it wasn't an 
analysis, it was just an indication of the possible performance hit on softfp, 
I'm sure you know the difference between a real analysis and an example.

> You chose sinf as an example of a common critical routine and made a big
>  show of the effect, predicting that softfp would be over a hundred cycles

woud be != could be. Obviously not all the vmovs are executed all the time, 
but there are cases where many of them will run. Some stalls may overlap, 
leading to a lesser drop in performance, but which _is_ there. Btw, your first 
reply seems to be missing some text after "However if the value came from 
memory", I'd be interested to see it completed.

>  slower (6 instructions * 20 cycle stalls).  In reality it's a dozen cycles
>  either way, with softfp being faster in some circumstances.

.. but slower overall, which again has been my point all the time. Anyway, no 
point arguing, people are able to choose for themselves I think. We (Genesi) 
are going for a hardfp port, one way or the other. The real question is, 
assuming we pick a suitable name (armhf), would Debian be interested in 
helping -and eventually adopting- this port? If not, we're wasting each 
other's time trying to prove the obvious.



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