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/*
* @test
* @bug 4892507
* @summary Basic Test for MemoryPool.resetPeakUsage()
* @author Mandy Chung
*
* @build ResetPeakMemoryUsage MemoryUtil
* @run main/othervm ResetPeakMemoryUsage
*/
import java.lang.management.*;
import java.util.*;
public class ResetPeakMemoryUsage {
private static MemoryMXBean mbean = ManagementFactory.getMemoryMXBean();
private static List pools = ManagementFactory.getMemoryPoolMXBeans();
private static MemoryPoolMXBean mpool = null;
public static void main(String[] argv) {
ListIterator iter = pools.listIterator();
while (iter.hasNext()) {
MemoryPoolMXBean p = (MemoryPoolMXBean) iter.next();
if (p.getType() == MemoryType.HEAP &&
p.isUsageThresholdSupported()) {
mpool = p;
System.out.println("Selected memory pool: ");
MemoryUtil.printMemoryPool(mpool);
break;
}
}
if (mpool == null) {
throw new RuntimeException("No heap pool found with threshold != -1");
}
MemoryUsage usage0 = mpool.getUsage();
MemoryUsage peak0 = mpool.getPeakUsage();
final long largeArraySize = (usage0.getMax() - usage0.getUsed()) / 10;
System.out.println("Before big object is allocated: ");
printMemoryUsage();
// Allocate a big array - need to allocate from the old gen
Object[][][] obj = new Object[1][1][(int) largeArraySize];
System.out.println("After the object is allocated: ");
printMemoryUsage();
MemoryUsage usage1 = mpool.getUsage();
MemoryUsage peak1 = mpool.getPeakUsage();
if (usage1.getUsed() <= usage0.getUsed()) {
throw new RuntimeException(
formatSize("Before allocation: used", usage0.getUsed()) +
" expected to be > " +
formatSize("After allocation: used", usage1.getUsed()));
}
if (peak1.getUsed() <= peak0.getUsed()) {
throw new RuntimeException(
formatSize("Before allocation: peak", peak0.getUsed()) +
" expected to be > " +
formatSize("After allocation: peak", peak1.getUsed()));
}
// The object is now garbage and do a GC
// memory usage should drop
obj = null;
mbean.gc();
System.out.println("After GC: ");
printMemoryUsage();
MemoryUsage usage2 = mpool.getUsage();
MemoryUsage peak2 = mpool.getPeakUsage();
if (usage2.getUsed() >= usage1.getUsed()) {
throw new RuntimeException(
formatSize("Before GC: used", usage1.getUsed()) + " " +
" expected to be > " +
formatSize("After GC: used", usage2.getUsed()));
}
if (peak2.getUsed() != peak1.getUsed()) {
throw new RuntimeException(
formatSize("Before GC: peak", peak1.getUsed()) + " " +
" expected to be equal to " +
formatSize("After GC: peak", peak2.getUsed()));
}
mpool.resetPeakUsage();
System.out.println("After resetPeakUsage: ");
printMemoryUsage();
MemoryUsage usage3 = mpool.getUsage();
MemoryUsage peak3 = mpool.getPeakUsage();
if (peak3.getUsed() != usage3.getUsed()) {
throw new RuntimeException(
formatSize("After resetting peak: peak", peak3.getUsed()) + " " +
" expected to be equal to " +
formatSize("current used", usage3.getUsed()));
}
if (peak3.getUsed() >= peak2.getUsed()) {
throw new RuntimeException(
formatSize("After resetting peak: peak", peak3.getUsed()) + " " +
" expected to be < " +
formatSize("previous peak", peak2.getUsed()));
}
System.out.println("Test passed.");
}
private static String INDENT = " ";
private static void printMemoryUsage() {
MemoryUsage current = mpool.getUsage();
MemoryUsage peak = mpool.getPeakUsage();
System.out.println("Current Usage: ");
MemoryUtil.printMemoryUsage(current);
System.out.println("Peak Usage: ");
MemoryUtil.printMemoryUsage(peak);
}
private static String formatSize(String name, long value) {
StringBuffer buf = new StringBuffer(name + " = " + value);
if (value > 0) {
buf.append(" (" + (value >> 10) + "K)");
}
return buf.toString();
}
}