OpenCL analysis... Darktable... much faster with Opencl disabled...something wrong??

[kofa (István Kovács)]

And if you compile yourself, make sure to create a ‘release build’.
--build-type Release instead of RelWithDebInfo.

This can have a huge performance impact (I’m not talking about 20%, but rather doubling the speed):

@kofa

@Claes : you say your machine is only ‘a little bit better’ than mine; but on the CPU path (OpenCL disabled) I got pixel pipeline processing took 275.756 secs (3153.805 CPU) (all 12 ‘hyperthreaded’ cores in use, CPU running at around 4.2 GHz), while you get 90 seconds… that’s hardly ‘a little bit’. (This is with ND800_0005626_anonymized.NEF, with just the default settings and Aurélien’s style.)

I’ve now recompiled with --build-type Release (I had not specified a build-type previously, so it used the default RelWithDebugInfo), and now got much better timings:

73.566043 [dev_pixelpipe] took 44.513 secs (495.844 CPU) processed `diffuse or sharpen' on CPU, blended on CPU [export]
89.567931 [dev_pixelpipe] took 16.002 secs (180.493 CPU) processed `diffuse or sharpen 1' on CPU, blended on CPU [export]
138.042138 [dev_pixelpipe] took 48.474 secs (551.746 CPU) processed `diffuse or sharpen 2' on CPU, blended on CPU [export]
...
140.268511 [dev_process_export] pixel pipeline processing took 112.221 secs (1261.094 CPU)