Hi Steve,
Thanks for answer.
Following is the code I used.
I created a dump by running GenHeap and invoking dumpHeap(..) from jconsole.
I wrote, that my dump was around ~370MB, but today when I regenerate it
it has ~440MB (maybe last time I took dump before all instances where
created).
Yesterday I tried to take a look into parser code, but I haven't yet
good image of what (and way) is going on there.
Regards,
Lukasz
--------------------------- Heap generator
------------------------------------------
import java.util.concurrent.ConcurrentLinkedQueue;
public class GenHeap {
private ConcurrentLinkedQueue<Data> queue;
public GenHeap(int size) {
queue = new ConcurrentLinkedQueue<Data>();
for (int i=0; i<size; ++i) {
queue.add(new Data());
}
}
private static GenHeap root;
public static void main(String[] args) throws Exception {
root = new GenHeap(Integer.parseInt(args[0]));
System.out.println("Ready for taking a dump.");
Thread.sleep(1000000);
System.out.println("root: "+root);
}
}
public class Data {
private static int counter = 0;
public int myid = ++counter;
}
---------------------------------------------------------------------------------------------------
------------------------ Analyzer
----------------------------------------------------------
package mykato;
import java.io.File;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryPoolMXBean;
import javax.tools.diagnostics.FactoryRegistry;
import javax.tools.diagnostics.image.Image;
import org.apache.kato.hprof.datalayer.HProfFactory;
import org.apache.kato.hprof.datalayer.HProfFile;
import org.apache.kato.hprof.datalayer.IHProfRecord;
import org.apache.kato.hprof.datalayer.IHeapDumpHProfRecord;
public class App {
public static void main(String[] args) throws Exception {
System.out.println("Hello World!");
String pathToDump = "/tmp/kato.hprof";
File dump = new File(pathToDump);
// defaultApproach(dump);
hprofReaderApproach(dump);
System.out.println("TaDa!");
}
private static void defaultApproach(File dump) throws Exception {
Image image = FactoryRegistry.getDefaultRegistry().getImage(dump);
}
private static void hprofReaderApproach(File dump) throws Exception {
HProfFile hprofFile = HProfFactory.createReader(dump);
// HProfFile hprofFile = new HProfFile(new
RandomAccesDataProvider(dump));
hprofFile.open();
int r = 0;
IHProfRecord record;
while ((record = hprofFile.getRecord(r)) != null) {
if (record instanceof IHeapDumpHProfRecord) {
processHeapDump((IHeapDumpHProfRecord)record);
}
++r;
}
}
private static void processHeapDump(IHeapDumpHProfRecord heapDump) {
System.out.println("heapDump: "+heapDump);
int r = 0;
long lastTimestamp = System.currentTimeMillis();
IHProfRecord record;
while ((record = heapDump.getSubRecord(r)) != null) {
if (++r % 100000 == 0) {
long timestamp = System.currentTimeMillis();
System.out.println("HeapSubRecord: "+r+"
("+(timestamp-lastTimestamp)+"ms, "+getMemoryUsed()+"kB)");
lastTimestamp = timestamp;
}
}
}
private static MemoryPoolMXBean oldGenPool;
static {
for (MemoryPoolMXBean pool :
ManagementFactory.getMemoryPoolMXBeans()) {
if (pool.getName().toLowerCase().contains("old")) {
oldGenPool = pool;
break;
}
}
System.out.println("MemoryPool: "+oldGenPool.getName());
}
private static long getMemoryUsed() {
return (int)(oldGenPool.getUsage().getUsed() / 1024);
}
}
--------------------------------------------------------------------------------------------------------------
Steve Poole wrote:
Thanks for this Luksz - you are probably the first person to use this
code other than the developers and its great to get some feedback. Can you
share the code you used to create the dump and to visit the HPROF records?
Stuart has made some performance adjustments to the hprof code and we'll see
if we can do better.
On the spec list we're discussing the basics of a "snapshot" dump concept
where only what you need gets dumped. I wonder if the same idea could be
applied to opening a dump. It would be great to know when reading a dump
that certain information is not required - that should improve
performance.
