How to deal with big files

As found discussed in some posts in this forum, the LinuxCNC user interface seems to do linear search in GCode somewhere, and thus gets exponentially slower with file size. Due to this issue it is (as far as I understand) necessary to disable the preview in larger files, using the "(AXIS,hide)" notation in the GCode file.

While this makes it possible to start the file in theory, I found in practice that it also means LinuxCNC does not tell me what the path boundaries are, which for me often is essential to check that I set my zero points correctly so they don't collide with workholding.

What is your process for dealing with large files? I tried to use another CAM (Camotics) to find the boundaries, before loading the file up in LinuxCNC, but frankly it is a hassle because it is yet another step in the process.

Is there an easier way to deal with large gcode files? Does any LinuxCNC user interface NOT suffer from the linear search preview problem?
 

Well, for me, it starts to become laggy at a file size of 1MB, and becomes unusable (dangerous, because e.g. pause buttons no longer work well during a job) at 2-3MB.

The files I *want* to work with are usually in the 10-30MB range, but honestly, I don't think the jobs are super complex and I will sooner or later want to go bigger still. Adaptive paths just become huge, fast. (I am using FreeCAD with LinuxCNC postprocessor - I haven't found it supports arcs.)

$ cat /proc/cpuinfo | head -5
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 122
model name : Intel(R) Celeron(R) J4125 CPU @ 2.00GHz

The machine has 8GB memory.
I had put some more info in this thread . The previous discussion I found was this one . There was another, but I'm not finding it right now.

But honestly, I think that the question about file size or PC performance is the wrong one - a UI with O(n²) performance (where n is the gcode size) is clearly not a good idea and will become a problem on any machine.
 

I think it's not good practice to throw resources at a problem that looks like a bug .

So, after digging into the LinuxCNC code for a few hours, I finally found the culprit. It's here:

github.com/LinuxCNC/linuxcnc/blob/master...s274/glcanon.py#L590

The calls to glCallList() take 25 seconds on a 700K gcode file.

I commented these calls out, and suddenly LinuxCNC is blazingly fast, with the preview still working. Even a 30 MB file takes only 10 seconds to open, after that the file doesn't cause any delays whatsoever.

github.com/LinuxCNC/linuxcnc/issues/2539