Author: sco...@google.com
Date: Tue Mar 31 13:55:44 2009
New Revision: 5139
Modified:
changes/scottb/memory/dev/core/src/com/google/gwt/dev/util/Memory.java
Log:
SQUASH into initial infrastructure; make this compile against Java 5 SDK.
Suggested by: spoon
Modified:
changes/scottb/memory/dev/core/src/com/google/gwt/dev/util/Memory.java
==============================================================================
--- changes/scottb/memory/dev/core/src/com/google/gwt/dev/util/Memory.java
(original)
+++ changes/scottb/memory/dev/core/src/com/google/gwt/dev/util/Memory.java
Tue Mar 31 13:55:44 2009
@@ -15,19 +15,38 @@
*/
package com.google.gwt.dev.util;
-import com.sun.management.HotSpotDiagnosticMXBean;
-
import java.io.File;
-import java.io.IOException;
import java.lang.management.ManagementFactory;
+import java.lang.reflect.Method;
/**
* Utility methods for dealing with VM memory.
*/
public class Memory {
+ /**
+ * Number of times to call System.gc() before measuring the memory
+ * usage/dumping the heap. This value was arrived at through
trial-and-error
+ * on the Sun JVM; memory usage seems to stabilize after 3 to 4 runs. We
think
+ * the reason it requires multiple runs is due to the generational
aspect of
+ * garbage collection.
+ */
+ private static final int NUM_GC_COLLECTIONS = 4;
+
+ /**
+ * Set this system property to a filename suffix to dump heaps into.
+ */
private static final String PROPERTY_DUMP_HEAP = "gwt.memory.dumpHeap";
+
+ /**
+ * Set this system property to dump memory usage at various points.
+ */
private static final String PROPERTY_DUMP_MEMORY = "gwt.memory.usage";
+
+ /**
+ * Time to start measuring since the last memory measurement/dump, or
+ * application startup.
+ */
private static long startTime;
public static void initialize() {
@@ -50,7 +69,7 @@
public static void maybeDumpMemory(String info) {
long elapsed = System.currentTimeMillis() - startTime;
if (System.getProperty(PROPERTY_DUMP_MEMORY) != null) {
- for (int i = 0; i < 10; ++i) {
+ for (int i = 0; i < NUM_GC_COLLECTIONS; ++i) {
System.gc();
}
long heap =
ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
@@ -65,14 +84,15 @@
dumpFile = info + "-" + dumpFile;
new File(dumpFile).delete();
try {
- HotSpotDiagnosticMXBean bean;
- bean = ManagementFactory.newPlatformMXBeanProxy(
+ Class<?> beanClass =
Class.forName("com.sun.management.HotSpotDiagnosticMXBean");
+ Object bean = ManagementFactory.newPlatformMXBeanProxy(
ManagementFactory.getPlatformMBeanServer(),
- "com.sun.management:type=HotSpotDiagnostic",
- HotSpotDiagnosticMXBean.class);
- bean.dumpHeap(dumpFile, true);
+ "com.sun.management:type=HotSpotDiagnostic", beanClass);
+ Method dumpHeapMethod = beanClass.getDeclaredMethod("dumpHeap",
+ String.class, Boolean.TYPE);
+ dumpHeapMethod.invoke(bean, dumpFile, true);
System.out.println("(" + info + ") dumped heap into: " + dumpFile);
- } catch (IOException e) {
+ } catch (Throwable e) {
System.err.println("Unable to dump heap");
e.printStackTrace();
}
--~--~---------~--~----~------------~-------~--~----~
http://groups.google.com/group/Google-Web-Toolkit-Contributors
-~----------~----~----~----~------~----~------~--~---
