send load information periodically even if not currently solicited. (#187)

src/DurableTask.Netherite/PartitionState/ActivitiesState.cs

@@ -40,6 +40,9 @@ namespace DurableTask.Netherite
         [DataMember]
         public DateTime[] TransferCommandsReceived { get; set; }
 
+        [IgnoreDataMember]
+        DateTime LastSentToLoadMonitor = DateTime.MinValue;
+
         [IgnoreDataMember]
         public override TrackedObjectKey Key => new TrackedObjectKey(TrackedObjectKey.TrackedObjectType.Activities);
 
@@ -107,13 +110,14 @@ namespace DurableTask.Netherite
         }
 
         // called frequently, directly from the StoreWorker. Must not modify any [DataMember] fields.
-        public void CollectLoadMonitorInformation()
+        public void CollectLoadMonitorInformation(DateTime now)
         {
             // send load information if there is a backlog of if it was solicited recently
             if (this.LocalBacklog.Count > 0  
                 || this.QueuedRemotes.Count > 0
+                || (now - this.LastSentToLoadMonitor) > TimeSpan.FromSeconds(10)
                 || (this.LastSolicitation.HasValue 
-                    && (DateTime.UtcNow - this.LastSolicitation.Value) < LoadMonitor.SOLICITATION_VALIDITY))
+                    && (now - this.LastSolicitation.Value) < LoadMonitor.SOLICITATION_VALIDITY))
             {          
                 this.Partition.Send(new LoadInformationReceived()
                 {
@@ -124,6 +128,7 @@ namespace DurableTask.Netherite
                     AverageActCompletionTime = this.AverageActivityCompletionTime,
                     TransfersReceived = (DateTime[]) this.TransferCommandsReceived.Clone()
                 });
+                this.LastSentToLoadMonitor = now;
             }
         }
 

src/DurableTask.Netherite/StorageProviders/Faster/StoreWorker.cs

@@ -487,7 +487,7 @@ namespace DurableTask.Netherite.Faster
                 if (this.partition.NumberPartitions() > 1 && this.partition.Settings.ActivityScheduler == ActivitySchedulerOptions.Locavore)
                 {
                     var activitiesState = (await this.store.ReadAsync(TrackedObjectKey.Activities, this.effectTracker)) as ActivitiesState;
-                    activitiesState.CollectLoadMonitorInformation();
+                    activitiesState.CollectLoadMonitorInformation(DateTime.UtcNow);
                 }
 
                 if (this.loadInfo.IsBusy() != null)