[Pkg-phototools-devel] Bug#855359: Bug#855359: darktable: 2.2.1 binary very slow compared to self-compiled

[Matthias Bodenbinder]

Am 05.03.2017 um 18:41 schrieb David Bremner:
> I'm not able to reproduce the large difference between the debian
> package and compiling with
> 
>  ./build.sh --disable-gnome-keyring --build-type Release
> 
> On my machine (an older i7), I get an average of 40s to export with
> 2.2.3-2 (compiled with -O3, just uploaded) and an average of 39s with
> the build.sh produced binary.  In both cases the time is dominated by
> the non-local means noise reduction (about 24s).
>
> Looking only at the time in the equalizer module, the improvement is a
> slightly larger (as a percentage) 7.9 seconds for build.sh versions 8.5
> seconds for the debian package. Given we can't use -march=native or
> -mtune=native, that's probably an acceptable slowdown.

This is really interesting. And puzzling. 

I am wondering if it has to do with the fact that I am using the latest Kaby Lake CPU i7-7700k? 

The Equalizer module in my case improves from 6,9 s to 3,0 s and non-local means noise reduction improves from 10,3 s to 8,7 s. 

They both sum up to 17,2 s with the debian testing binary and 11,7 s with my self-compiled binary. This is a 32% difference. 

What else can I do to help debugging? 

Matthias