Ressource limits and large images

[Wolfgang Reissenberger]

Dear all,
I’m experiencing currently crashes of EKOS running on a Raspberry 4 with Raspbian 10. Meanwhile, I can reproduce the error. The problem is that allocation of new memory fails when a new image gets loaded.

As a workaround I can resolve it if I turn off completely the FITS viewer.

To reproduce it, you need the current 32bit Raspbian 10 and do the following:
- use CCD Simulator and increase the image size to the maximal vaules 8192x8192
- run the focuser (one completed capture is sufficient)
- run an alignment (2x2 binning is sufficient)
- start a capture sequence
Typically after the second frame, KStars crashes with 

The reason is, that we have several places where images and associated pixmaps are used: Manager, Focuser, Align, FitsViewer. In each place, at least one QImage and one QPixmap is stored. With the setup above, each QPixmap object is 256 MB.

One solution is that for such sensors we should recommend 64Bit OS versions. As far as I understand, 32Bit OS have a memory limit which we are touching with big frame sizes.

As an alternative, we could rework EKOS in such a way, that we shift all images to the FITS viewer and in case of a low resource mode, only one image is held at one time, i.e. capturing, focusing and alignment share the same pixmap. This would drastically reduce memory consumption.

What do you think about this?

Cheers
Wolfgang

—
Wolfgang Reissenberger

www.sterne-jaeger.de
TSA-120 + FSQ-85 | Avalon Linear + M-zero | Moravian G2-8300 + ASI 1600mm pro + ASI 6200mm pro

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