Date: Wed, 14 Aug 2002 16:03:08 +0800 From: Huang wen hui <hwh@mail.gddsn.org.cn> To: "Bill Huey (Hui)" <billh@gnuppy.monkey.org> Cc: java <java@FreeBSD.ORG> Subject: Re: Hotspot vm is extremely slower than nojit vm on current ? Message-ID: <3D5A0EBC.9060706@mail.gddsn.org.cn> References: <3D59C6A4.5020708@mail.gddsn.org.cn> <20020814030231.GA4285@gnuppy.monkey.org>
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Bill Huey (Hui) :
>On Wed, Aug 14, 2002 at 10:55:32AM +0800, Huang wen hui wrote:
>
>
>>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.
>>
>>
>...
>
>
>>^^^^^^
>>%~hwh/jre/bin/java -jar TestTimer.jar ; java -jar TestTimer.jar
>>query elapse time: 1354
>>query elapse time: 140221
>>^^^^^^
>>
>>
>
>I could have blown it with the sleep math. Previously I multiplied the
>value of nanosleep by a 1000x more than it should be. ;)
>
>bill
>
>
>
>
>
Do you mean you have fixed this bug? Would you mind send the patch to me ?
More info of this bug, if this is no sense, I'll apologize.
This bug occured in hotspot compiler[1 2] vm, not core vm. and I
simplify the test case:
The main thread elapse time is exactly as same as the timer sleep time.
%~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)
Java HotSpot(TM) Core VM (build 1.3.1-internal, interpreted mode)
%~hwh/jre/bin/java TestTimer
sleep time: 2006
%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)
%java TestTimer
sleep time: 100013
-----------------------------------------------------------------------------------------------------------------------
public class Timer extends Thread{
private static ThreadGroup tGroup = new ThreadGroup("Timer");
// Number of seconds in each timer cycle
int m_cycle;
private boolean bQuit = false;
public Timer(int cycle){
super(tGroup,"TimerThread");
m_cycle = cycle;
}
public void run(){
this.setName("TimerThread");
// Loop until stopped
while (!bQuit) {
try {
// Sleep for the clock cycle
sleep(m_cycle * 1000);
}
catch (InterruptedException ex) {
}
}
}
public void quit() {
bQuit = true;
}
}
import java.util.*;
/**
* Test freebsd Hotspot speed.
*/
public class TestTimer {
Timer timer = new Timer(100);
public TestTimer() {
timer.start();
}
public void destoryTimer() {
timer.quit();
}
public static void main(String[] args) throws Exception{
TestTimer tt =new TestTimer();
long now = new java.util.Date().getTime();
Thread.sleep(2*1000);
System.err.println("sleep time: "+ (new java.util.Date().getTime() -
now));
tt.destoryTimer();
}
}
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