Enblend 4.2.4 and OpenMP

[FabKzo]

Hi all,

I'm using Hugin 2019 , packaged with enblend 4.2.4  with openMp support ( using 8 processors and up to 8 threads )  on Ubuntustudio 19.04 - while it works I find it ( enblend processing only ) very slow compared to my previous installation based on enblend 4.1.4 .

So i'm testing many options to speed it up (  mask optimizations , colorspace (no-ciecam) etc etc ... ) and I force number of threads to use in hugin interface ( made to affect the value to  $OMP_NUM_THREADS I presume ),

With those options the process is almost 40% faster than it was at fresh install, but I've noticed that while openMp is active only 1 thread is used to generate Gaussian and Laplacian pyramids . Is that a normal behaviour?