Date: Wed, 14 Aug 2002 10:55:32 +0800 From: Huang wen hui <hwh@mail.gddsn.org.cn> To: java <java@FreeBSD.ORG> Subject: Hotspot vm is extremely slower than nojit vm on current ? Message-ID: <3D59C6A4.5020708@mail.gddsn.org.cn>
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hi,
Mostly hotspot vm is stable and fast, but I got problem with Thread.sleep.
Look at the following simple program, on current hotspot vm is extreamly
slow.
%java -version
java version "1.3.1-p7"
Java(TM) 2 Runtime Environment, Standard Edition (build
1.3.1-p7-root-020727-22:30)
Java HotSpot(TM) Client VM (build 1.3.1-internal, mixed mode)
%~hwh/jre/bin/java -version
java version "1.3.1-p7"
Java(TM) 2 Runtime Environment, Standard Edition (build
1.3.1-p7-root-020727-22:30)
Classic VM (build 1.3.1-p7-root-020727-22:30, green threads, nojit)
%~hwh/jre/bin/java -jar TestTimer.jar ; java -jar TestTimer.jar
query elapse time: 1230
query elapse time: 160177
^^^^^^
%~hwh/jre/bin/java -jar TestTimer.jar ; java -jar TestTimer.jar
query elapse time: 1407
query elapse time: 160256
^^^^^^
%~hwh/jre/bin/java -jar TestTimer.jar ; java -jar TestTimer.jar
query elapse time: 1354
query elapse time: 140221
^^^^^^
---------------------------------------------------------------------------------------------------------
import java.util.*;
import cn.gd.util.Timer;
import cn.gd.util.TimerListener;
import java.sql.*;
public class TestTimer implements cn.gd.util.TimerListener {
Timer timer = new Timer(this,20);
public TestTimer() {
timer.start();
}
public synchronized void TimerEvent(Object object) {
}
public void destoryTimer() {
timer.quit();
}
public void query(){
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
Connection conn =
DriverManager.getConnection("jdbc:mysql://localhost/seismic?user=test&password=test");
String sql = "select * from station";
Statement st = conn.createStatement();
ResultSet rs = null;
for(int i=0;i<100;i++) {
rs = st.executeQuery(sql);
while(rs.next()) {
String sta = rs.getString("sta");
//System.out.println("sta is: "+sta);
}
rs.close();
}
st.close();
conn.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception{
TestTimer tt =new TestTimer();
long now = new java.util.Date().getTime();
//Thread.sleep(60*1000);
tt.query();
System.err.println("query elapse time: "+ (new
java.util.Date().getTime() - now));
tt.destoryTimer();
}
}
public class Timer extends Thread{
private static ThreadGroup tGroup = new ThreadGroup("Timer");
// TimerListener to receive TimerEvent notifications
TimerListener m_timerListener;
// Number of seconds in each timer cycle
int m_cycle;
// Object to be supplied with the TimerEvent notification
Object m_object;
private boolean bQuit = false;
public Timer(TimerListener timerListener, int cycle){
super(tGroup,"TimerThread");
m_timerListener = timerListener;
m_cycle = cycle;
m_object = null;
}
public Timer(TimerListener timerListener, int cycle,
Object object){
super(tGroup,"TimerThread");
m_timerListener = timerListener;
m_cycle = cycle;
m_object = object;
}
public void run(){
this.setName("TimerThread");
// Loop until stopped
while (!bQuit) {
try {
// Sleep for the clock cycle
sleep(m_cycle * 1000);
}
catch (InterruptedException ex) {
}
// Fire a TimerEvent
if (m_timerListener != null) {
m_timerListener.TimerEvent(m_object);
}
}
}
public void quit() {
bQuit = true;
}
}
public interface TimerListener
{
void TimerEvent(Object object);
}
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