Revert to 2.10.32?

[rich2005]

@David, it is worth investigating. A test with my large tif image, open in Gimp 2.10.34 and precision upped to 16 bit. Size in Gimp now 1.3 GB

Make a fuzzy selection / selection to channel / mask from channel / invert colour. Takes a minute here. My kubuntu 20.04 laptop / i5-8core / 16 GB memory. (ie. nothing special)

https://i.imgur.com/hhaPTTp.mp4

I only wish I could offer some suggestions but I do not have any. If you run Gimp with the Dashboard dock open does that show anything ?

[Ofnuts]

16-bit FP is a bad choice. Yes, you save on RAM (but you don't need to do that it seems), and it implies a lot of conversions. Using 32-bit FP is normally somewhat faster (32-bit FP linear is the native format, so all conversions are skipped)

[david]

@Rich, thanks for the suggestion.
The source image I have been using is https://discuss.pixls.us/t/queens-view-w...ists/36739

I loaded the .TIF from this image and did a fuzzy-select on the landscape (this is 2/3 of the whole image!).

I have attached a screen-shot of the dashboard. Cache and Memory are what I would expect - the image loads as 852.8 MB.
CPU is sitting at 12%, does this imply that it is only using one of it's eight cores for this process?

After about 15 minutes with no result, I closed Gimp.

   

@Ofnuts. The reason for using 16bit Fixed Point is that is what is output by Filmulator after converting to .TIF.
In order to compare with previous results I stayed with this precision.

[rich2005]

@David

I get very much the same as you: CPU ( < 15% ) / Memory Use 2.2 GB / Cache 1.4 GB / No swap, except all done in a minute.

I put the stopwatch on this again to show total time and used Nufraw to import. Cut the selection at the end just to show what it is. This is kubuntu 20.04 / Gimp 2.10.34

https://i.imgur.com/V08qzFi.mp4

I have number of cores threads set as default (1 ). Could it be some dodgy memory in your computer ?

[Ofnuts]

(04-24-2023, 08:28 AM)david Wrote: @Rich, thanks for the suggestion.
The source image I have been using is https://discuss.pixls.us/t/queens-view-w...ists/36739

I loaded the .TIF from this image and did a fuzzy-select on the landscape (this is 2/3 of the whole image!).

I have attached a screen-shot of the dashboard. Cache and Memory are what I would expect - the image loads as 852.8 MB.
CPU is sitting at 12%, does this imply that it is only using one of it's eight cores for this process?

After about 15 minutes with no result, I closed Gimp.



@Ofnuts. The reason for using 16bit Fixed Point is that is what is output by Filmulator after converting to .TIF.
In order to compare with previous results I stayed with this precision.

There are two different CPU uses... one is to make the selection, and one is to display it. What I find is that a fuzzy selection on a real-life photo has "ants" all over, and it is the display of the ants animation that is using the CPU (Ctrl-T to hide the ants drop the CPU uses to 0 in the dashboard and silences the CPU fan ).

[david]

@Ofnuts.
I load the image and make a fuzzy selection. In the View menu, clicking Show Selection does not hide the "ants", but Ctrl-T does.
After the "ants" are cleared I can do Select/Save to Channel and the result is instantaneous.

I can get the ants to then re-appear, either by going to the View menu and clicking Show Selection, or with Ctrl-T.

I am totally confused!!!

[Ofnuts]

(04-24-2023, 11:20 AM)david Wrote: @Ofnuts.
I load the image and make a fuzzy selection. In the View menu, clicking Show Selection does not hide the "ants", but Ctrl-T does.
After the "ants" are cleared I can do Select/Save to Channel and the result is instantaneous.

I can get the ants to then re-appear, either by going to the View menu and clicking Show Selection, or with Ctrl-T.

I am totally confused!!!

When you max ou CPUs thing can get bizarre. The keyboard is interrupt-driven so keyboard shortcuts pass through, and I suspect menu interaction involves windows updates which require the same CPU thread as the animation so can be postponed for a long while.

[david]

@Rich.
To try to eliminate a possible RAM problem, I swapped banks 1&4. When that made no difference, swapped banks 2&3 - no change.
I am reluctant to do a Memtest, with 32 GB it will take forever!

[david]

Ofnuts & Rich.

Thanks for all your help and advice.

I have reached the following conclusions. You may wish to comment if these are correct.
1. Fuzzy Select and Select by Colour use only one processor core.
2. If there are enough "crawling ants" on the screen the processor will go to maximum and be unable to process software IRQs.
3. Ctrl-T, as a keyboard IRQ, has a high priority and any software IRQ is then processed instantly.
4. Changing the precision to 32 bit floating point does not prevent the problem if enough "ants" are on the screen.

With the number of pixels increasing in newer cameras the lack of multi-core processing could become a problem. Let us hope this will be solved when we get Gimp 3.

At least, I now know how to get round the problem - Ctrl-T.