4 ms·

Yes this is correct. The worst part is currently the mono version Unity uses has a 'stop the world' garbage collector, the worse kind for a game as at 60 fps al

Yes this is correct. The worst part is currently the mono version Unity uses has a 'stop the world' garbage collector, the worse kind for a game as at 60 fps allocations quickly add up and the game can constantly freeze frame. The hoops you have to jump through to work around this make for some ugly code.

iamcreasy 11y ago
So everybody using Unity makes their games in a way so the GC never stop the game?
- jharger 11y ago
  Yes, and it's a huge pain! We have to pool game object instances, and sometimes even have to attempt to force GC to prevent things from freezing every few seconds.
  - yarou 11y ago
    That's horrifying. Is there any way to disable the GC and manually manage memory? I don't remember if the C# spec supports this, because it's been years since I've written in it (and Mono didn't exist back then).
    - jharger 11y ago
      So there is... using the "unsafe" pointers and fixed keyword, etc. The Unity interfaces don't support that, though, so for things like dynamically updating textures and vertex data, you're pretty much stuck with GC.
    - obsurveyor 11y ago
      You "disable" the GC in Unity by never allocating anything new after initializing the game. It's a great learning experience to update code to this and it's practically required for mobile.
  - vvanders 11y ago
    I've got a little secret: We do the same thing in native code. malloc() and free() can be almost as expensive as a GC in aggregate(it's a matter of paying the cost at creation vs GC time). Pooling is a really nice performance tool, just requires a bit of hand tuning to the scenario.
    - iamcreasy 11y ago
      So Pooling is a performance tool for both cases? Native and GC.
      - pmalynin 11y ago
        Pooling has a lot of nice properties, like data locality that games can benefit from greatly especially in situations relying on tight loop like calling update on every game component or particle.
        vvanders 11y ago
        Yup, sadly that's something you lose in GC'd languages.
  - stcredzero 11y ago
    There was a Squeak based game emulator/debugger shown at one Smalltalk Solutions. The developer talked about doing tricks, like turning off the GC. You'd know which objects were persistent, and which weren't, and at the beginning of the game tick, everything that wasn't persistent was assumed to go away. No scanning the heap at all.
  - blaisio 11y ago
    It's really not that different from how games written in languages like C++ are implemented though. It's impossible to avoid the object pooling idea if you want maximum performance.

iamcreasy 11y ago

So everybody using Unity makes their games in a way so the GC never stop the game?

jharger 11y ago
Yes, and it's a huge pain! We have to pool game object instances, and sometimes even have to attempt to force GC to prevent things from freezing every few seconds.
- yarou 11y ago
  That's horrifying. Is there any way to disable the GC and manually manage memory? I don't remember if the C# spec supports this, because it's been years since I've written in it (and Mono didn't exist back then).
  - jharger 11y ago
    So there is... using the "unsafe" pointers and fixed keyword, etc. The Unity interfaces don't support that, though, so for things like dynamically updating textures and vertex data, you're pretty much stuck with GC.
  - obsurveyor 11y ago
    You "disable" the GC in Unity by never allocating anything new after initializing the game. It's a great learning experience to update code to this and it's practically required for mobile.
- vvanders 11y ago
  I've got a little secret: We do the same thing in native code. malloc() and free() can be almost as expensive as a GC in aggregate(it's a matter of paying the cost at creation vs GC time). Pooling is a really nice performance tool, just requires a bit of hand tuning to the scenario.
  - iamcreasy 11y ago
    So Pooling is a performance tool for both cases? Native and GC.
    - pmalynin 11y ago
      Pooling has a lot of nice properties, like data locality that games can benefit from greatly especially in situations relying on tight loop like calling update on every game component or particle.
      - vvanders 11y ago
        Yup, sadly that's something you lose in GC'd languages.
- stcredzero 11y ago
  There was a Squeak based game emulator/debugger shown at one Smalltalk Solutions. The developer talked about doing tricks, like turning off the GC. You'd know which objects were persistent, and which weren't, and at the beginning of the game tick, everything that wasn't persistent was assumed to go away. No scanning the heap at all.
- blaisio 11y ago
  It's really not that different from how games written in languages like C++ are implemented though. It's impossible to avoid the object pooling idea if you want maximum performance.