Photon Realtime Extensions: StripKeysWithNullValues and GC Alloc

Hi everyone,
In our current project, we use Photon room properties to sync entities. and i noticed some heavy GC Allocs while deep profiling the game and it always ends down to this Method.


Have anyone faced this issue before ? or attempted to fix it ?


  • Changed the implementation to reduce GC.
    /// <summary>
            /// This removes all key-value pairs that have a null-reference as value.
            /// Photon properties are removed by setting their value to null.
            /// Changes the original passed IDictionary!
            /// </summary>
            /// <param name="original">The IDictionary to strip of keys with null-values.</param>
            public static List<object> keysToRemove = new List<object>(); 
            public static void StripKeysWithNullValues(this IDictionary original)
                 * by making keysToRemove a static variable that you clear before using. It will trigger allocations only during the warm-up phase
                 * as the list needs to grow. Once it's hit the high water mark for keys you need to remove. it will not allocate further during steady-state operation.
                foreach (DictionaryEntry entry in original)
                    if (entry.Value == null)
                foreach (var key in keysToRemove)
                //object[] keys = new object[original.Count];
                //original.Keys.CopyTo(keys, 0);
                //for (int index = 0; index < keys.Length; index++)
                //    object key = keys[index];
                //    if (original[key] == null)
                //    {
                //        original.Remove(key);
                //    }
  • Yes, this should be better to use.
    I guess you would be fine with this being used for Photon / PUN?
  • Sure
  • The downside of this implementation is that it's not thread safe.
    I guess we'll have to pool this.