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List:       gcc
Subject:    Re: Some thoughts about steerring commitee work
From:       Tobias Burnus <burnus () gmx ! de>
Date:       2007-06-16 0:37:23
Message-ID: 467330C3.7050802 () gmx ! de
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Vladimir N. Makarov wrote:
> Eric Botcazou wrote:
>>> Please, just look at those charts
>>>
>>> https://vmakarov.108.redhat.com/nonav/spec/comparison.html
>>>
>>> The compilation speed decrease without a performance improving (at least
>>> for the default case) is really scary.
>>>   
>>
>> Right, I also found those charts a bit depressing, given the time and
>> energy that have been put in the compiler since GCC 3.2.3.


To cheer you up, you can look at the number for gfortran with the
Polyhedron benchmark:

http://physik.fu-berlin.de/~tburnus/gcc-trunk/benchmark/#rt

gfortran 4.1.3 is up to 119% slower than gfortran 4.3, whereas the speed
regressions are maximally 12%.
For the geometric mean, gfortran 4.2 needs 12% longer than 4.3

(All values for AMD64.)

Looking at the geometric mean of the 16 tests, 4.3. is only 5% slower
than Intel's ifort 9.1, 6% than ifort 10.0 and sunf95, and 16% slower
than Pathscale.*

I think this is not bad at all!

Tobias

PS: The df merge has caused speed regression (geometric mean) of around 1%.

*One can probably better tune the parameter of all the compilers.
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