Memory management

General Discussion Other

danhett

in General Discussion • Other • 2 years ago

Hi all

I'm creating an augmented reality installation that uses a number of external libraries (jmyron, ARtoolkit, OBJloader and a fullscreen helper), and includes a 6000 polygon textured model, rendered in OpenGL mode.

It all works brilliantly, but: after a few minutes I get an Out Of Memory error and the program halts. I've already bumped up Processing's memory allocation to 1.5GB, and this improved it a little, but I'm still getting the problem.

Interestingly, I added a handler that calls System.gc() every time I click. This seems to hold the problem at bay (as far as I can see anyway). I was considering just calling this at arbitrary time intervals, but this seems really dirty :)

What I'd rather do is optimise my project so it plays nicely, does anyone have any pointers on optimising either AR or 3D in Processing? I can post my source here if needed.

Thanks in advance!

Replies(6)

amnon.owed

Re: Memory management

2 years ago

It would indeed help if you post the runnable code or put it in a zip or something.

Are you using PGraphics by any chance?

danhett

Re: Memory management

2 years ago

Nope, I'm not using PGraphics.

I've actually made some progress with this. As a test, I added a rudimentary frame counter that triggers System.gc() every time it counts to the limit I set. This solution works great (I left my app running for an hour and it was fine). However this still seems like a relatively crappy way of doing things, so I want to look at the memory usage directly, and when it gets under a certain threshold it should trigger the garbage collector.

However, if I trace out free memory in my draw() function, I get odd results. I would expect the amount of free memory to start off high, and then count lower and lower until either the garbage collector automatically triggers, or the program throws an OutOfMemoryError. What I get instead is:

1.62882E7 (I get this once)

1.5287616E7 (this is repeated identically for a few minutes)

6779528 (this repeats for a few draw cycles)

6483264 (this repeats for a few too)

Then the program hangs due to being out of memory.

This seems like really odd behaviour... am I interpreting this correctly? Slightly confused about it!

Dan

amnon.owed

Re: Memory management

2 years ago

Yeah, I noticed that the memory seems to work in 'chunks'. So only when you are nearing the end, you will see the actual total and free memory.

Have you tried something like this?

if (Runtime.getRuntime().freeMemory() > 1000000) {
// add or do stuff
} else {
System.gc(); // optionally add one of these
}

PhiLho

Re: Memory management

2 years ago

There is nothing wrong to trigger the GC regularly, for a program aiming at near real time behavior, or having the issue you expose.
Another way is to reuse memory, avoiding to create large chunks of memory at once. Not standard Java (which shouldn't care about memory usage) but sometime needed.

Now, if you want a finer analysis of your program, look at the jvisualvm program coming with the Java JDK, in the bin directory (where java.exe or similar for your platform lives).

amnon.owed

Re: Re: Memory management

2 years ago

Awesome. I'm going to be working on my slitscanning stuff again and memory is a big issue, so this jvisualvm will come in very handy. Thanks for the tip!

danhett

Re: Memory management

2 years ago

Sounds good, I'll check that out. The interval trigger works well enough, I just come from a Flash background and have always tried to avoid doing stuff like that. As it stands though, my problem is solved, it was more a question of method really, I'm quite new to this stuff.