Finally hunted down the Parallel deadlock. Packets were being handled asynchronously (filling up the threadpool with handlers), which would turn around and try to do parallel operations on the starved threadpool. The solution for now is to disable Parallel.cs operations until we can gracefully handle parallel operations with a potentially starved threadpool

2 files changed, 10 insertions, 7 deletions

diff --git a/OpenSim/Region/Framework/Scenes/Scene.cs b/OpenSim/Region/Framework/Scenes/Scene.cs
index 6c34056..42051d0 100644
--- a/OpenSim/Region/Framework/Scenes/Scene.cs
+++ b/OpenSim/Region/Framework/Scenes/Scene.cs
@@ -120,7 +120,7 @@ namespace OpenSim.Region.Framework.Scenes
         private readonly Timer m_restartTimer = new Timer(15000); // Wait before firing
         private int m_incrementsof15seconds;
         private volatile bool m_backingup;
-        private bool m_useAsyncWhenPossible = true;
+        private bool m_useAsyncWhenPossible;
 
         private Dictionary<UUID, ReturnInfo> m_returns = new Dictionary<UUID, ReturnInfo>();
         private Dictionary<UUID, SceneObjectGroup> m_groupsWithTargets = new Dictionary<UUID, SceneObjectGroup>();
@@ -480,7 +480,7 @@ namespace OpenSim.Region.Framework.Scenes
                 IConfig startupConfig = m_config.Configs["Startup"];
 
                 // Should we try to run loops synchronously or asynchronously?
-                m_useAsyncWhenPossible = startupConfig.GetBoolean("use_async_when_possible", true);
+                m_useAsyncWhenPossible = startupConfig.GetBoolean("use_async_when_possible", false);
 
                 //Animation states
                 m_useFlySlow = startupConfig.GetBoolean("enableflyslow", false);
@@ -4261,10 +4261,13 @@ namespace OpenSim.Region.Framework.Scenes
 
         public void ForEachClient(Action<IClientAPI> action, bool doAsynchronous)
         {
-            if (doAsynchronous)
-                m_clientManager.ForEach(action);
-            else
-                m_clientManager.ForEachSync(action);
+            // FIXME: Asynchronous iteration is disabled until we have a threading model that
+            // can support calling this function from an async packet handler without
+            // potentially deadlocking
+            //if (doAsynchronous)
+            //    m_clientManager.ForEach(action);
+            //else
+            //    m_clientManager.ForEachSync(action);
         }
 
         public bool TryGetClient(UUID avatarID, out IClientAPI client)
diff --git a/bin/OpenSim.ini.example b/bin/OpenSim.ini.example
index 2adc87f..4f1799e 100644
--- a/bin/OpenSim.ini.example
+++ b/bin/OpenSim.ini.example
@@ -49,7 +49,7 @@
     ; in parallel. Running in parallel should increase performance
     ; on a multi-core system, but will make debugging more
     ; difficult if something deadlocks or times out
-    use_async_when_possible = true
+    use_async_when_possible = false
     
     ; Max threads to allocate on the FireAndForget thread pool
     ; when running with the SmartThreadPool option above