Re: Polyhedron speed comparison (on AMD64)

[Paul Thomas <paulthomas2 at wanadoo dot fr>]

Tobias,
> First, you remember our big regression for ae on AMD64? This has now
> been partially fixed by Uros (using x87 for fmod):
>   
Thanks, Uros!
> Thus we are not yet back at our original speed, maybe one should find
> the reason for the extra 2s step at Nov 13/14.
>   
Nothing stands out in fortran or libgfortran, does it?
> A reduce C test case: gcc 0m7.2s and icc 0m2.4s. I filled PR30032.
> If anyone has an idea what gfortran or GCC should do better ...
>   
So what do you reckon, Andrew?
> (1) linpk FAILED    1 fails and    4 passes
>     Value= 25.114499300     Target= 23.100000000     Tolerance= 2.0000000000
>   
Is this new? I do not recall seeing it.
> Result of May 2006 (there with standard.par test; above with quick.par):
> Test               g95     gfortran 4.2   gfortran 4.1   ifort 9.0   ifort 9.1   NAGf95
> ------------   ----------  ----------     -------------  ----------  ----------  ----------
>   Geom. Mean   33.36[100]  26.16[ 78]     26.49[ 79]     24.10[ 72]  22.99[ 69]  27.95[ 84]
>
>
> We should check why we get the wrong result in linpk
> -- and why we are that slow in fatigue.
Hmmm!
> e.
>
> At least with the mean speed we have improved: 25.7 vs. 26.2s,
> whereas Intel as regressed 22.9 vs. 23.1s.
>
>   
Fixing gas_dyn and fatigue would close the gap.

Thanks for keeping an eye on this.

Paul