Using 4049.
When exporting a very large grayscale image (16k*16k), after a successful build, the WM writes the result to disk extremely slowly. This appears to be unresponsive, but Task Manager shows that the WM file writes the result to disk at approximately 4.7ms/s.
By the way, I believe my hardware resources are adequate; I did not observe any memory leaks during the build:
CPU: Intel(R) Xeon(R) Gold 6130 CPU
RAM: 96GB
GPU: Nvidia P4000
What file format are you writing with?
I’m going to hazard a guess that it’s one of the raw formats. You’re right, the exporters for those are quite old and written inefficiently. I’ve actually already patched this for the next version as a result of your report!
If it’s not a raw, please let me know which one you’re encountering issues with.
I exported in PNG format, and the size of a single image is about 300+M
The disk I wrote to is HDD instead of SSD, but even for HDD, this is too slow
hmm, that is surprising to me. For PNG exports, World Machine uses libpng, which is the standard and default library for creating png files. I would not expect that to be abnormally slow (merely the expected amount of slow for a compressed file format)
I’ve found some similar references to very slow png export in libpng with large files elsewhere (Making sure you're not a bot! as one example in GIMP). This is unfortunate, but there’s not much else to do about it short of using a non-official png library optimized for speed.
For now, I’d recommend using TIFF as an export format instead, which is efficiently implemented for large files.
pngtest.tmd (402.4 KB)
This is a simplified reproduction of the problem.
(Perhaps someone could try exporting this project to see if it caused same issue)