perf: NetworkIdentity dirty masks via callbacks instead of iteration

Assets/Mirror/Core/NetworkBehaviour.cs

@@ -150,10 +150,21 @@ protected void SetSyncVarHookGuard(ulong dirtyBit, bool value)
                 syncVarHookGuard &= ~dirtyBit;
         }
 
+        // callback for both SyncObject and SyncVar dirty bit setters.
+        // called once it becomes dirty, not called again while already dirty.
+        // -> we only want to follow the .netIdentity memory indirection once
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        void OnBecameDirty()
+        {
+            netIdentity.OnBecameDirty(this);
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         void SetSyncObjectDirtyBit(ulong dirtyBit)
         {
+            bool clean = syncObjectDirtyBits == 0;
             syncObjectDirtyBits |= dirtyBit;
+            if (clean) OnBecameDirty();
         }
 
         /// <summary>Set as dirty so that it's synced to clients again.</summary>
@@ -161,7 +172,9 @@ void SetSyncObjectDirtyBit(ulong dirtyBit)
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SetSyncVarDirtyBit(ulong dirtyBit)
         {
+            bool clean = syncVarDirtyBits == 0;
             syncVarDirtyBits |= dirtyBit;
+            if (clean) OnBecameDirty();
         }
 
         /// <summary>Set as dirty to trigger OnSerialize & send. Dirty bits are cleared after the send.</summary>

Assets/Mirror/Core/NetworkIdentity.cs

@@ -218,6 +218,14 @@ public static Dictionary<uint, NetworkIdentity> spawned
         // which means we can't allow > 64 components (it's enough).
         const int MaxNetworkBehaviours = 64;
 
+        // NetworkBehaviour's dirty masks.
+        // set from NetworkBehaviour.OnBecameDirty callback.
+        ulong serverOwnerInitialMask;     // all initial components' bits are set
+        ulong serverOwnerDirtyMask;       // only dirty  components' bits are set
+        ulong serverObserversDirtyMask;   // all initial components' bits are set
+        ulong serverObserversInitialMask; // only dirty  components' bits are set
+        ulong clientDirtyMask;            // only dirty components. client doesn't send initial.
+
         // current visibility
         //
         // Default = use interest management
@@ -313,12 +321,30 @@ internal void InitializeNetworkBehaviours()
             NetworkBehaviours = GetComponents<NetworkBehaviour>();
             ValidateComponents();
 
+            // reset the masks before initializing them.
+            // during tests, we may create an identity, then change sync mode,
+            // then call Awake() to initialize the masks properly.
+            // if we don't reset them first, then we OR into the first state.
+            serverOwnerInitialMask = serverObserversInitialMask = 0;
+
             // initialize each one
             for (int i = 0; i < NetworkBehaviours.Length; ++i)
             {
                 NetworkBehaviour component = NetworkBehaviours[i];
                 component.netIdentity = this;
                 component.ComponentIndex = (byte)i;
+
+                ulong nthBit = (1u << component.ComponentIndex);
+
+                // build a mask with all owner components' bits set for initialState
+                // -> for initial, all components are synced to owner no matter what.
+                // -> so simply set a bit for every component index
+                serverOwnerInitialMask |= nthBit;
+
+                // build a mask with all observer components' bits set initialState
+                // -> for initial, only SyncMode.Observers components are synced
+                if (component.syncMode == SyncMode.Observers)
+                    serverObserversInitialMask |= nthBit;
             }
         }
 
@@ -833,29 +859,28 @@ internal void OnStopAuthority()
             }
         }
 
-        // build dirty mask for server owner & observers (= all dirty components).
+        // NetworkBehaviour OnBecameDirty calls NetworkIdentity callback with index
-        // faster to do it in one iteration instead of iterating separately.
+        internal void OnBecameDirty(NetworkBehaviour component)
-        (ulong, ulong) ServerDirtyMasks(bool initialState)
         {
-            ulong ownerMask    = 0;
+            ulong nthBit = (1u << component.ComponentIndex);
-            ulong observerMask = 0;
 
-            NetworkBehaviour[] components = NetworkBehaviours;
+            // ensure either isServer or isClient are set.
-            for (int i = 0; i < components.Length; ++i)
+            // ensures tests are obvious. without proper setup, it should throw.
+            if (!isClient && !isServer)
+                Debug.LogWarning("NetworkIdentity.OnBecameDirty(): neither isClient nor isServer are true. Improper setup?");
+
+            // set for server & client both.
+            // OnSerialize will decide how to use them.
+            if (isServer)
             {
-                NetworkBehaviour component = components[i];
-
-                bool dirty = component.IsDirty();
-                ulong nthBit = (1u << i);
-
                 // owner needs to be considered for both SyncModes, because
                 // Observers mode always includes the Owner.
                 //
                 // for initial, it should always sync owner.
                 // for delta, only for ServerToClient and only if dirty.
                 //     ClientToServer comes from the owner client.
-                if (initialState || (component.syncDirection == SyncDirection.ServerToClient && dirty))
+                if (component.syncDirection == SyncDirection.ServerToClient)
-                    ownerMask |= nthBit;
+                    serverOwnerDirtyMask |= nthBit;
 
                 // observers need to be considered only in Observers mode
                 //
@@ -863,21 +888,10 @@ internal void OnStopAuthority()
                 // for delta, only if dirty.
                 // SyncDirection is irrelevant, as both are broadcast to
                 // observers which aren't the owner.
-                if (component.syncMode == SyncMode.Observers && (initialState || dirty))
+                if (component.syncMode == SyncMode.Observers)
-                    observerMask |= nthBit;
+                    serverObserversDirtyMask |= nthBit;
             }
-
+            if (isClient)
-            return (ownerMask, observerMask);
-        }
-
-        // build dirty mask for client.
-        // server always knows initialState, so we don't need it here.
-        ulong ClientDirtyMask()
-        {
-            ulong mask = 0;
-
-            NetworkBehaviour[] components = NetworkBehaviours;
-            for (int i = 0; i < components.Length; ++i)
             {
                 // on the client, we need to consider different sync scenarios:
                 //
@@ -887,16 +901,13 @@ ulong ClientDirtyMask()
                 //     serialize only if owned.
 
                 // on client, only consider owned components with SyncDirection to server
-                NetworkBehaviour component = components[i];
                 if (isOwned && component.syncDirection == SyncDirection.ClientToServer)
                 {
                     // set the n-th bit if dirty
                     // shifting from small to large numbers is varint-efficient.
-                    if (component.IsDirty()) mask |= (1u << i);
+                    clientDirtyMask |= (1u << component.ComponentIndex);
                 }
             }
-
-            return mask;
         }
 
         // check if n-th component is dirty.
@@ -920,12 +931,9 @@ internal void SerializeServer(bool initialState, NetworkWriter ownerWriter, Netw
 
             // check which components are dirty for owner / observers.
             // this is quite complicated with SyncMode + SyncDirection.
-            // see the function for explanation.
+            // see InitializeNetworkBehaviours and OnBecameDirty for explanations.
-            //
+            ulong ownerMask    = initialState ? serverOwnerInitialMask     : serverOwnerDirtyMask;
-            // instead of writing a 1 byte index per component,
+            ulong observerMask = initialState ? serverObserversInitialMask : serverObserversDirtyMask;
-            // we limit components to 64 bits and write one ulong instead.
-            // the ulong is also varint compressed for minimum bandwidth.
-            (ulong ownerMask, ulong observerMask) = ServerDirtyMasks(initialState);
 
             // if nothing dirty, then don't even write the mask.
             // otherwise, every unchanged object would send a 1 byte dirty mask!
@@ -985,7 +993,7 @@ internal void SerializeClient(NetworkWriter writer)
             // instead of writing a 1 byte index per component,
             // we limit components to 64 bits and write one ulong instead.
             // the ulong is also varint compressed for minimum bandwidth.
-            ulong dirtyMask = ClientDirtyMask();
+            ulong dirtyMask = clientDirtyMask;
 
             // varint compresses the mask to 1 byte in most cases.
             // instead of writing an 8 byte ulong.
@@ -1325,6 +1333,10 @@ internal void Reset()
         // clear all component's dirty bits no matter what
         internal void ClearAllComponentsDirtyBits()
         {
+            serverOwnerDirtyMask     = 0;
+            serverObserversDirtyMask = 0;
+            clientDirtyMask          = 0;
+
             foreach (NetworkBehaviour comp in NetworkBehaviours)
             {
                 comp.ClearAllDirtyBits();

Assets/Mirror/Tests/Editor/NetworkIdentitySerializationTests.cs

@@ -44,10 +44,18 @@ public void SerializeAndDeserializeAll()
             serverOwnerComp.syncMode     = clientOwnerComp.syncMode     = SyncMode.Owner;
             serverObserversComp.syncMode = clientObserversComp.syncMode = SyncMode.Observers;
 
+            // syncMode was changed after spawning.
+            // need to reinitialize the initial masks.
+            serverIdentity.InitializeNetworkBehaviours();
+
             // set unique values on server components
             serverOwnerComp.value = "42";
             serverObserversComp.value = 42;
 
+            // TODO FIX
+            // ownerWriter: has owner comp and observers comp (since it's for owner)
+            // observers writer: only has the comp for observers
+
             // serialize server object
             serverIdentity.SerializeServer(true, ownerWriter, observersWriter);
 
@@ -87,7 +95,11 @@ public void SerializationException()
 
             // set sync modes
             serverCompExc.syncMode = clientCompExc.syncMode = SyncMode.Observers;
-            serverComp2.syncMode = clientComp2.syncMode = SyncMode.Owner;
+            serverComp2.syncMode   = clientComp2.syncMode   = SyncMode.Owner;
+
+            // syncMode was changed after spawning.
+            // need to reinitialize the initial masks.
+            serverIdentity.InitializeNetworkBehaviours();
 
             // set unique values on server components
             serverComp2.value = "42";
@@ -270,30 +282,35 @@ public void SerializeAndDeserialize_ClientToServer_NOT_OWNED()
         [Test]
         public void SerializeServer_OwnerMode_ClientToServer()
         {
-            CreateNetworked(out GameObject _, out NetworkIdentity identity,
+            CreateNetworkedAndSpawn(
-                out SyncVarTest1NetworkBehaviour comp);
+                out _, out NetworkIdentity serverIdentity, out SyncVarTest1NetworkBehaviour serverComp,
+                out _, out NetworkIdentity clientIdentity, out SyncVarTest1NetworkBehaviour clientComp);
 
             // pretend to be owned
-            identity.isOwned = true;
+            serverIdentity.isOwned = true;
-            comp.syncMode = SyncMode.Owner;
+            serverComp.syncMode = SyncMode.Owner;
 
             // set to CLIENT with some unique values
             // and set connection to server to pretend we are the owner.
-            comp.syncDirection = SyncDirection.ClientToServer;
+            serverComp.syncDirection = SyncDirection.ClientToServer;
-            comp.value = 12345;
+            serverComp.value = 12345;
+
+            // syncMode was changed after spawning.
+            // need to reinitialize the initial masks.
+            serverIdentity.InitializeNetworkBehaviours();
 
             // initial: should still write for owner
-            identity.SerializeServer(true, ownerWriter, observersWriter);
+            serverIdentity.SerializeServer(true, ownerWriter, observersWriter);
             Debug.Log("initial ownerWriter: " + ownerWriter);
             Debug.Log("initial observerWriter: " + observersWriter);
             Assert.That(ownerWriter.Position, Is.GreaterThan(0));
             Assert.That(observersWriter.Position, Is.EqualTo(0));
 
             // delta: ClientToServer comes from the client
-            ++comp.value; // change something
+            ++serverComp.value; // change something
             ownerWriter.Position = 0;
             observersWriter.Position = 0;
-            identity.SerializeServer(false, ownerWriter, observersWriter);
+            serverIdentity.SerializeServer(false, ownerWriter, observersWriter);
             Debug.Log("delta ownerWriter: " + ownerWriter);
             Debug.Log("delta observersWriter: " + observersWriter);
             Assert.That(ownerWriter.Position, Is.EqualTo(0));
@@ -309,6 +326,7 @@ public void SerializeServer_ObserversMode_ClientToServer()
                 out SyncVarTest1NetworkBehaviour comp);
 
             // pretend to be owned
+            identity.isServer = true;
             identity.isOwned = true;
             comp.syncMode = SyncMode.Observers;
 
@@ -317,6 +335,10 @@ public void SerializeServer_ObserversMode_ClientToServer()
             comp.syncDirection = SyncDirection.ClientToServer;
             comp.value = 12345;
 
+            // syncMode was changed after spawning.
+            // need to reinitialize the initial masks.
+            identity.InitializeNetworkBehaviours();
+
             // initial: should write something for owner and observers
             identity.SerializeServer(true, ownerWriter, observersWriter);
             Debug.Log("initial ownerWriter: " + ownerWriter);
@@ -324,6 +346,9 @@ public void SerializeServer_ObserversMode_ClientToServer()
             Assert.That(ownerWriter.Position, Is.GreaterThan(0));
             Assert.That(observersWriter.Position, Is.GreaterThan(0));
 
+            // reset dirty bits after serializing
+            identity.ClearAllComponentsDirtyBits();
+
             // delta: should only write for observers
             ++comp.value; // change something
             ownerWriter.Position = 0;