3 ms·

C# uses a generational gc iirc so it may be better suited for a system where you have a relativly stable collection that does not need to be fully garbage colle

by erk__ 7y ago

C# uses a generational gc iirc so it may be better suited for a system where you have a relativly stable collection that does not need to be fully garbage collected all the time and have a smaller and more volitile set of objects that will be gc'ed more often. I don't think the current garbage collector in go does anything similar to that.

danbolt 7y ago
This might have changed with more recent updates, but I was under the impression that the Mono garbage collector in Unity was a bit dated and not as up-to-date as a C# one today.
- martindevans 7y ago
  Unity has recently added the "incremental GC" [1] which spreads the work of the GC over multiple frames. As I understand it this has a lower overall throughput, but _much_ better worst case latency. [1] https://blogs.unity3d.com/2018/11/26/feature-preview-incremental-garbage-collection/ https://blogs.unity3d.com/2018/11/26/feature-preview-increme...
to11mtm 7y ago
Yeah, that's the ideal pattern in C#. You have to be smart-ish about it, but writing low GC pressure code can be easier than you think. Keep your call stacks shallow, avoid certain language constructs (i.e. LINQ) or at least know when they really make sense for the cost (async). IDK if this is true for earlier versions, but as of today C# has pretty clear rules: 16MB in desktop or 64MB in server (which type is used can be set via config) will trigger a full GC [1]. Note that less than that may trigger a lower level GC, but those are usually not the ones that are noticed. I'm guessing at least some of that is because of memory locality as well as the small sizes. On the other hand, in a lot of the Unity related C# posts I see on forums/etc, passing structs around is considered the 'performant' way to do things to minimize GC pressure. [1] https://docs.microsoft.com/en-us/dotnet/standard/garbage-collection/fundamentals#conditions_for_a_garbage_collection https://docs.microsoft.com/en-us/dotnet/standard/garbage-col... [2] https://blog.golang.org/ismmkeynote https://blog.golang.org/ismmkeynote

by erk__ 7y ago

danbolt 7y ago

This might have changed with more recent updates, but I was under the impression that the Mono garbage collector in Unity was a bit dated and not as up-to-date as a C# one today.

martindevans 7y ago
Unity has recently added the "incremental GC" [1] which spreads the work of the GC over multiple frames. As I understand it this has a lower overall throughput, but _much_ better worst case latency. [1] https://blogs.unity3d.com/2018/11/26/feature-preview-incremental-garbage-collection/ https://blogs.unity3d.com/2018/11/26/feature-preview-increme...

to11mtm 7y ago

Yeah, that's the ideal pattern in C#. You have to be smart-ish about it, but writing low GC pressure code can be easier than you think. Keep your call stacks shallow, avoid certain language constructs (i.e. LINQ) or at least know when they really make sense for the cost (async). IDK if this is true for earlier versions, but as of today C# has pretty clear rules: 16MB in desktop or 64MB in server (which type is used can be set via config) will trigger a full GC [1]. Note that less than that may trigger a lower level GC, but those are usually not the ones that are noticed. I'm guessing at least some of that is because of memory locality as well as the small sizes. On the other hand, in a lot of the Unity related C# posts I see on forums/etc, passing structs around is considered the 'performant' way to do things to minimize GC pressure. [1] https://docs.microsoft.com/en-us/dotnet/standard/garbage-collection/fundamentals#conditions_for_a_garbage_collection https://docs.microsoft.com/en-us/dotnet/standard/garbage-col... [2] https://blog.golang.org/ismmkeynote https://blog.golang.org/ismmkeynote