C# Compiler Holy moly! Alloc appreciation thread

Code (csharp):

1. using UnityEngine;
2. using System.Collections.Generic;
3.  
4. public class Test : MonoBehaviour {
5.  
6.     public int[] ints = {1, 2, 3};
7.     public List<int> instList = new List<int> {1, 2, 3};
8.     public int sum;
9.  
10.     private void Update() {
11.         //5.3.6.p1:                         0 alloc
12.         //5.3.5.p8-csharp-compiler-upgrade: 0 alloc
13.         foreach (var i in ints) {
14.             sum += i;
15.         }
16.  
17.         //5.3.6.p1:                         40B alloc
18.         //5.3.5.p8-csharp-compiler-upgrade: 0   alloc!
19.         foreach (var i in instList) {
20.             sum += i;
21.         }
22.     }
23. }

Welcome to the future!

 

ABOUT FRICKIN' TIME!

Meanwhile, in a secret Unity Technologies lab, they can now allocate their resources to easier things - like making pigs fly.

 

It's the future, only on a different timeline, the 5.3 timeline that is.

 

Will this be part of the 5.5 beta from the start then?

 

Thank you!

 

Orb, your profile pic is most disturbing I've ever seen.

That is all.

 

@JoshPeterson, I just ran a test build of World To The West with the 5.3.8 version. It's about 1-2 hour worth of gameplay in about 30ish scenes, and everything worked perfectly. No bugs! Or, well, no bugs that wasn't already there.

 

Great news!

 

Does anyone know if this stops the Dictionary GC alloc with an enum TKey? I would guess not, since it still needs to be boxed for IsEquals, but I'd love to be wrong.

 

Thanks for your interest @JoshPeterson

Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4. using System.Collections.Generic;
5.  
6. public class DictionaryAlloc : MonoBehaviour
7. {
8.     public enum TimeZones
9.     {
10.         EST,
11.         EDT
12.     }
13.  
14.     private Dictionary<TimeZones, float> m_allocDictionary = new Dictionary<TimeZones, float>();
15.  
16.     private Dictionary<TimeZones, float> m_noAllocDictionary = new Dictionary<TimeZones, float>(new TimeZoneEnumCompare());
17.     private class TimeZoneEnumCompare : IEqualityComparer<TimeZones>
18.     {
19.         public bool Equals(TimeZones a, TimeZones b)
20.         {
21.             return (int)a == (int)b;
22.         }
23.  
24.         public int GetHashCode(TimeZones a)
25.         {
26.             return (int)a;
27.         }
28.     }
29.  
30.     private float m_dummyMath = 0;
31.     private float m_curVal = 0;
32.     private bool m_allocMode = true;
33.  
34.     void Start ()
35.     {
36.         m_allocDictionary.Add(TimeZones.EST, 1);
37.         m_allocDictionary.Add(TimeZones.EDT, 2);
38.         m_noAllocDictionary.Add(TimeZones.EST, 1);
39.         m_noAllocDictionary.Add(TimeZones.EDT, 2);
40.     }
41.  
42.     void Update ()
43.     {
44.         if(Input.GetKeyDown(KeyCode.Space))
45.         {
46.             m_allocMode = !m_allocMode;
47.         }
48.  
49.         if(m_allocMode)
50.         {
51.             AccessAllocDictionary();
52.         }
53.         else
54.         {
55.             AccessNoAllocDictionary();
56.         }
57.     }
58.  
59.     private void AccessAllocDictionary()
60.     {
61.         // ContainsKey is 60B Editor/Standalone GCAlloc
62.         if (m_allocDictionary.ContainsKey(TimeZones.EST))
63.         {
64.             m_dummyMath += 1;
65.         }
66.  
67.         // Direct access is 60B Editor/Standalone GC Alloc
68.         m_dummyMath += m_allocDictionary[TimeZones.EDT];
69.  
70.         // TryGetValue is 60B Editor/Standalone GC Alloc
71.         if (m_allocDictionary.TryGetValue(TimeZones.EDT, out m_curVal))
72.         {
73.             m_dummyMath += m_curVal;
74.         }
75.     }
76.  
77.     // After writing a comparator dictionary they no longer alloc
78.     private void AccessNoAllocDictionary()
79.     {
80.         if (m_noAllocDictionary.ContainsKey(TimeZones.EST))
81.         {
82.             m_dummyMath += 1;
83.         }
84.  
85.         m_dummyMath += m_noAllocDictionary[TimeZones.EDT];
86.  
87.         if (m_noAllocDictionary.TryGetValue(TimeZones.EDT, out m_curVal))
88.         {
89.             m_dummyMath += m_curVal;
90.         }
91.     }
92. }
93.  

I'd really like to not be penalized for every enum dictionary/hash by needing to write an IEqualityComparer class object. If this could be done auto-magically it would be super.

 

@JoshPeterson I ran the Unity profiler on both editor and standalone with this script attached to the main camera I didn't look at the IL. Thank you very much for testing it though. I still look forward to being able to use foreach again.