Garbage Collection and Best Practices for Memory Management?

Comments

• zvardin Member

  July 2012

  I'm somewhat new to this, so I can't answer too well, but I do know you can call collectgarbage() manually. I had at least once instance in my tests where I had to do this because I was relying on the collector with a weak table by key setup.

  +1 -1Share on Facebook
• petec Member

  July 2012

  You can use

  print(math.floor(collectgarbage("count")))

  to see how much memory is being used. I use it when changing scenes to check for memory leaks.
  I also collect garbage a few times before this as I've found it helps me see if it's my code that's causing memory build up or just a delay in automatic garbage collection, so I actually use:

  collectgarbage() collectgarbage() collectgarbage() print(math.floor(collectgarbage("count")))

  +1 -1Share on Facebook
• ___ Member

  July 2012

  @petec That looks nice!
  
  Do you do anything special when changing scenes, to make sure that the objects are released? How much memory leak do you normally see when changing scenes with/without manual garbage collection?

  People call me "underscore".

  +1 -1Share on Facebook
• petec Member

  July 2012

  I just make sure that I manually remove any objects that are not added to the scene sprite (e.g. if I have used stage:addChild(object) ). I also make sure that I remove any eventListeners - although I think (but don't know!) that event listeners attached to objects should be removed when the object is removed.
  
  Memory use seems to depend on what sort of things are in the scene, but what I watch out for is that it dooesn't keep building up. I sometimes see a small increase for a while but it flattens out and stops increasing and then, as garbage collection does it work, tends to drop back again. When I have a leak, then I see the memory use steadily increase continuously.
  

  +1 -1Share on Facebook
• ___ Member

  July 2012

  @petec
  
  Just ran your code on my game. Usage seems pretty stable.

  Memory Usage: 214 Memory Usage: 217 Memory Usage: 222 Memory Usage: 252 Memory Usage: 266 Memory Usage: 234 Memory Usage: 256 Memory Usage: 287 Memory Usage: 310 Memory Usage: 339 Memory Usage: 351 Memory Usage: 380 Memory Usage: 403 Memory Usage: 437 Memory Usage: 459 Memory Usage: 308 Memory Usage: 324 Memory Usage: 353 Memory Usage: 357 Memory Usage: 360 Memory Usage: 376 Memory Usage: 379 Memory Usage: 383 Memory Usage: 412 Memory Usage: 434 Memory Usage: 462 Memory Usage: 478 Memory Usage: 410 Memory Usage: 340 Memory Usage: 369 Memory Usage: 384 Memory Usage: 413 Memory Usage: 429 Memory Usage: 453 Memory Usage: 477 Memory Usage: 511 Memory Usage: 530 Memory Usage: 558 Memory Usage: 474 Memory Usage: 347 Memory Usage: 359 Memory Usage: 388 Memory Usage: 410 Memory Usage: 439

  Question: What unit is this number in?

  People call me "underscore".

  +1 -1Share on Facebook
• petec Member

  July 2012

  No idea!

  +1 -1Share on Facebook
• ___ Member

  July 2012

  Maybe @atilim can help :-B

  People call me "underscore".

  +1 -1Share on Facebook
• GregBUG Guru

  July 2012

  according to:
  
  http://pgl.yoyo.org/luai/i/collectgarbage
  
  "count": returns the total memory in use by Lua (in Kbytes).
  
  

  TNT ENGiNE for Gideors Studio - Particle Engine, Virtual Pad, Animator Studio, Collision Engine - DOWNLOAD NOW !!! IT'S FREE!!! -
  www.tntengine.com

  +1 -1Share on Facebook
• ___ Member

  July 2012

  Hmm. Any way to measure the total memory usage? The memory that will be used by a real device. With textures and all...

  People call me "underscore".

  +1 -1Share on Facebook