From 227126adb784ed70739f42aec0072bdd8f06de9a Mon Sep 17 00:00:00 2001
From: "Justin Clark-Casey (justincc)" <jjustincc@googlemail.com>
Date: Wed, 25 Jul 2012 22:38:28 +0100
Subject: [PATCH] Add MemoryWatchdog class missing from git master a1e9964

---
 OpenSim/Framework/MemoryWatchdog.cs | 129 ++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 OpenSim/Framework/MemoryWatchdog.cs

diff --git a/OpenSim/Framework/MemoryWatchdog.cs b/OpenSim/Framework/MemoryWatchdog.cs
new file mode 100644
index 0000000000..1e93077ac5
--- /dev/null
+++ b/OpenSim/Framework/MemoryWatchdog.cs
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using log4net;
+
+namespace OpenSim.Framework
+{
+    /// <summary>
+    /// Experimental watchdog for memory usage.
+    /// </summary>
+    public static class MemoryWatchdog
+    {
+//        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+        /// <summary>
+        /// Is this watchdog active?
+        /// </summary>
+        public static bool Enabled
+        {
+            get { return m_enabled; }
+            set
+            {
+//                m_log.DebugFormat("[MEMORY WATCHDOG]: Setting MemoryWatchdog.Enabled to {0}", value);
+
+                if (value && !m_enabled)
+                    UpdateLastRecord(GC.GetTotalMemory(false), Util.EnvironmentTickCount());
+
+                m_enabled = value;
+            }
+        }
+        private static bool m_enabled;
+
+        /// <summary>
+        /// Average memory churn in bytes per millisecond.
+        /// </summary>
+        public static double AverageMemoryChurn
+        {
+            get { if (m_samples.Count > 0) return m_samples.Average(); else return 0; }
+        }
+
+        /// <summary>
+        /// Maximum number of statistical samples.
+        /// </summary>
+        /// <remarks>
+        /// At the moment this corresponds to 1 minute since the sampling rate is every 2.5 seconds as triggered from
+        /// the main Watchdog.
+        /// </remarks>
+        private static int m_maxSamples = 24;
+
+        /// <summary>
+        /// Time when the watchdog was last updated.
+        /// </summary>
+        private static int m_lastUpdateTick;
+
+        /// <summary>
+        /// Memory used at time of last watchdog update.
+        /// </summary>
+        private static long m_lastUpdateMemory;
+
+        /// <summary>
+        /// Memory churn rate per millisecond.
+        /// </summary>
+        private static double m_churnRatePerMillisecond;
+
+        /// <summary>
+        /// Historical samples for calculating moving average.
+        /// </summary>
+        private static Queue<double> m_samples = new Queue<double>(m_maxSamples);
+
+        public static void Update()
+        {
+            int now = Util.EnvironmentTickCount();
+            long memoryNow = GC.GetTotalMemory(false);
+            long memoryDiff = memoryNow - m_lastUpdateMemory;
+
+            if (memoryDiff >= 0)
+            {
+                if (m_samples.Count >= m_maxSamples)
+                    m_samples.Dequeue();
+
+                double elapsed = Util.EnvironmentTickCountSubtract(now, m_lastUpdateTick);
+
+                // This should never happen since it's not useful for updates to occur with no time elapsed, but
+                // protect ourselves from a divide-by-zero just in case.
+                if (elapsed == 0)
+                    return;
+
+                m_samples.Enqueue(memoryDiff / (double)elapsed);
+            }
+
+            UpdateLastRecord(memoryNow, now);
+        }
+
+        private static void UpdateLastRecord(long memoryNow, int timeNow)
+        {
+            m_lastUpdateMemory = memoryNow;
+            m_lastUpdateTick = timeNow;
+        }
+    }
+}
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