Lens Correction only uses one core

[Hans-Peter huth]

Hi,

i noticed that automatic lens correction (currently DK 5.5) is very slow and
uses only one CPU core. When doing this in Gimp (lensfun-plugin), its way
faster and uses all cores.

Is this a bug or are there some reasons for this?

HP

--
--------- 8< -------------
Why taunt me? Why upbraid me? I am merely a genius, not a god.
(Nero Wolfe)
Meine Bilder: http://jalbum.net/a/1456383

[Gilles Caulier-4]

I can confirm that Lensfun filter from source code is not ported to QtConcurrent for multi-core support as all other filers from digiKam core.

If i remember, the re-entrance of lensfun algorithm was unknown. But as Gimp do it, so this can be done also in digiKam of course.

Please report this problem in KDE bugzilla into digiKam/ImageEditor-Tool-LensDistorsion section.

Thanks in advance

Gilles Caulier

2017-04-14 13:53 GMT+02:00 Hans-Peter <[hidden email]>:

Hi,

i noticed that automatic lens correction (currently DK 5.5) is very slow and
uses only one CPU core. When doing this in Gimp (lensfun-plugin), its way
faster and uses all cores.

Is this a bug or are there some reasons for this?

HP

--
--------- 8< -------------
Why taunt me? Why upbraid me? I am merely a genius, not a god.
(Nero Wolfe)
Meine Bilder: http://jalbum.net/a/1456383

[Torsten Bronger]

Hallöchen!

Hans-Peter writes:

> i noticed that automatic lens correction (currently DK 5.5) is
> very slow and uses only one CPU core. When doing this in Gimp
> (lensfun-plugin), its way faster and uses all cores.
>
> Is this a bug or are there some reasons for this?

Lensfun indeed contains no parallel execution of code.  I don't know
for sure why this is but I suspect that the original Lensfun
designer expected the calling program to vectorise tasks.  For
example, different regions of the image can be corrected calling
Lensfun concurrently.  Moreover, when mass-converting RAWs to JPEGs,
images can be processed in parallel.

Having parallel execution on both levels, Lensfun and
Digikam/Darktable/whatever, is probably not a good idea.

Tschö,
Torsten.

--
Torsten Bronger

[Gilles Caulier-4]

I palatalized the code of DK Lensfun filter :

https://bugs.kde.org/show_bug.cgi?id=378804

It still a little dysfunction at init, but 90% of the work is done. It just need to be finalized...

Gilles Caulier

2017-04-17 16:17 GMT+02:00 Torsten Bronger <[hidden email]>:

Hallöchen!

Hans-Peter writes:

> i noticed that automatic lens correction (currently DK 5.5) is
> very slow and uses only one CPU core. When doing this in Gimp
> (lensfun-plugin), its way faster and uses all cores.
>
> Is this a bug or are there some reasons for this?

Lensfun indeed contains no parallel execution of code.  I don't know
for sure why this is but I suspect that the original Lensfun
designer expected the calling program to vectorise tasks.  For
example, different regions of the image can be corrected calling
Lensfun concurrently.  Moreover, when mass-converting RAWs to JPEGs,
images can be processed in parallel.

Having parallel execution on both levels, Lensfun and
Digikam/Darktable/whatever, is probably not a good idea.

Tschö,
Torsten.

--
Torsten Bronger