Author: timfox Date: 2009-12-02 15:51:57 -0500 (Wed, 02 Dec 2009) New Revision: 8508 Added: trunk/src/main/org/hornetq/utils/MemorySize.java Log: added missing class Added: trunk/src/main/org/hornetq/utils/MemorySize.java =================================================================== --- trunk/src/main/org/hornetq/utils/MemorySize.java (rev 0) +++ trunk/src/main/org/hornetq/utils/MemorySize.java 2009-12-02 20:51:57 UTC (rev 8508) @@ -0,0 +1,143 @@ +/* + * Copyright 2009 Red Hat, Inc. + * Red Hat licenses this file to you under the Apache License, version + * 2.0 (the "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * http://www.apache.org/licenses/LICENSE-2.0 + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or + * implied. See the License for the specific language governing + * permissions and limitations under the License. + */ + +package org.hornetq.utils; + +import java.lang.ref.WeakReference; + +import org.hornetq.core.logging.Logger; + +/** + * A MemorySize + * + * @author Clebert Suconic + * @author Tim Fox + * + * + */ +public class MemorySize +{ + private static final Logger log = Logger.getLogger(MemorySize.class); + + private static final int numberOfObjects = 10000; + + private static Object newObject(final ObjectFactory factory) throws Exception + { + return factory.createObject(); + } + + public static boolean is64bitArch() + { + boolean is64bit = true; //Default to 64 e.g. if can't retrieve property + + try + { + String arch = System.getProperty("os.arch"); + + if (arch != null) + { + is64bit = arch.contains("64"); + } + } + catch (Exception e) + { + //Ignore + } + + return is64bit; + } + + public interface ObjectFactory + { + Object createObject(); + } + + public static int calculateSize(final ObjectFactory factory) throws Exception + { + final Runtime runtime = Runtime.getRuntime(); + + getMemorySize(runtime); + + newObject(factory); + + int i = 0; + long heap1 = 0; + long heap2 = 0; + long totalMemory1 = 0; + long totalMemory2 = 0; + + //First we do a dry run with twice as many then throw away the results + + Object[] obj = new Object[numberOfObjects * 2]; + + for (i = 0; i < numberOfObjects * 2; i++) + { + obj[i] = newObject(factory); + } + + obj = new Object[numberOfObjects * 2]; + + heap1 = getMemorySize(runtime); + + totalMemory1 = runtime.totalMemory(); + + for (i = 0; i < numberOfObjects; i++) + { + obj[i] = newObject(factory); + } + + heap2 = getMemorySize(runtime); + + totalMemory2 = runtime.totalMemory(); + + final int size = Math.round(((float)(heap2 - heap1)) / numberOfObjects); + + if (totalMemory1 != totalMemory2) + { + //throw new IllegalStateException("Warning: JVM allocated more data what would make results invalid " + + // totalMemory1 + ":" + totalMemory2); + + log.warn("Warning: JVM allocated more data what would make results invalid " + + totalMemory1 + ":" + totalMemory2); + } + + return size; + } + + private static long getMemorySize(final Runtime runtime) + { + for (int i = 0; i < 5; i++) + { + forceGC(); + } + return runtime.totalMemory() - runtime.freeMemory(); + } + + private static void forceGC() + { + WeakReference<Object> dumbReference = new WeakReference<Object>(new Object()); + // A loop that will wait GC, using the minimal time as possible + while (dumbReference.get() != null) + { + System.gc(); + try + { + Thread.sleep(500); + } + catch (InterruptedException e) + { + } + } + } + +}