DT is not displaying any debug information. Pls. see the video.
Hallojsa!
Why do you command “… darktable.exe darktable -d opencl”
instead of just “… darktable.exe -d opencl” ?
Mvh
Claes fra Lund i Sverige
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Good catch on that one… I missed that subtlety. Although at least in Linux, that extra “bogus” commandline argument (of the program name getting repeated) seems to get ignored when I try it.
I’m wondering if this is some sort of strange windows-ism…
I’d also add that if is a laptop, then you likely have switchable graphics, meaning you can alternate between the Intel and nvidia cards (and the system may automatically switch between them). I’d make sure the nvidia card is forced on while doing this.
Yes that is a known behaviour:
following the link you will get the info where the log output is written to:
I read a lot of information in the manual to turn on some debug settings, but I cannot see any debug information. Where can I find those debug logs?
The Windows version of dt by default logs its debug information to the following places:
Windows 10:
C:\Users\[username]\AppData\Local\Microsoft\Windows\INetCache\darktable\darktable-log.txt
Hi’ @Claes
Have a look no difference. I tried to repeat “darktable” to make it work and forgot to go back to the original version. Have a look:
1 Does this build have debug enabled?
2 Maybe you need to redirect output to file? E.g., for PhotoFlow,
photoflow > log.txt 2>&1
You can try installing and running Microsoft DebugView. That is how I get debug info from digiKam on Windows. Just run DebugView in parallel and see if darktable prints anything in there.
Hi’ @afre
Thank you for your response.
It’s an official “release” how do I know if debug is enabled or not?
You suggest that I should start darktable like this:
“darktable……………….exe” -d opencl > log.txt 2>&1 and then output should be found in a file called log somewhere on the pc?
Ok, I will try that tomorrow when I have more time.
Thanks I will try to do that.
I am able to run darktable with the specified options. Spaces are important otherwise you get an error message. But NetCache is not to be found?
Result can’t be found. No NetCache:
It is INetCache and you are right, it is hidden. Just copy and paste the full path in the explorer.
Also, after you start darktable with the opencl command you should also do some operations over the image that use opencl. Otherwise the log will contain a last message saying opencl is not used 
Hi’ @Daniel_Catalina
Thanks, this was a succes! But not something you can easily deduct from the DT manual! Here is the result:
Much to my surprise NVIDIA is 0 and Intel 1. So NVIDIA should be used the most by default, but this is not the case?
Looks like it is not going to work. I just tried it myself and saw no output from darktable in DebugView. Looks like darktable is not very verbose.
Hi’ @Andrius
Thanks for your help. As you see in the previous post I managed to see the debug output in the log file.
Hi’ @Daniel_Catalina and all others
Problem solved.
Realizing that NVIDIA is no. 0 and Intel no. 1 it turns out that the following setting makes NVIDIA to become the preferred GPU:
opencl_device_priority=!1,“star”/“star”/“star”/“star”
Many thanks to everyone………
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Hi’ Everyone
On my pc NVIDIA GPU is no. 0 and Intel GPU is no. 1.
It turns out that the setting opencl_device_priority = !1,“star”/!1,“star”/!1,“star”/!1,“star” works very well in respect to directing all graphic work to NVIDIA.
How do I determine if this is the best setting in respect to darktable overall performance on windows? Good ideas will be appreciated.