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hot spot optimization techniques?

stephan schweitzer
Greenhorn

Joined: Oct 26, 2003
Posts: 9
Hi,
I am searching for some information about the techniques used
in the hotspot vm. No general informations. What I really
need are informations about the techniques used in the virtual
machine and which preconditions must be fulfilled so that the
techniques are applicable.
thanks stephan
Ilja Preuss
author
Sheriff

Joined: Jul 11, 2001
Posts: 14112
What do you need this for? I do ask because this is a quite general (and possibly hard to answer) question, so knowing more about your needs might help us helping you...


The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
Ernest Friedman-Hill
author and iconoclast
Marshal

Joined: Jul 08, 2003
Posts: 24187
    
  34

Note that if you license the Java source from Sun (you can do this at no cost), then you can see the HotSpot code for yourself.


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Howard Kushner
author
Ranch Hand

Joined: Sep 19, 2003
Posts: 361
Hello Stephan,
Do you google? A quick google turns up:
  • http://java.sun.com/products/hotspot/whitepaper.html
  • http://www.javaworld.com/javaworld/jw-03-1998/jw-03-hotspot.html


  • I came across a JavaOne presentation once, but I can't seem to find it right now.
    Hope this help.
    Regards,


    Howard Kushner<br />IBM Certified Enterprise Developer - WebSphere Studio Application Developer V5.0<br />IBM Certified Advanced System Administrator - WebSphere Application Server V5.0<br />IBM Certified Solution Developer - Web Services with WebSphere Studio V5.1<br /><a href="http://www.amazon.com/exec/obidos/tg/detail/-/1931182108/" target="_blank" rel="nofollow">Developing J2EE Applications with WebSphere Studio</a> my Certification Study Guide for IBM Test 287
    stephan schweitzer
    Greenhorn

    Joined: Oct 26, 2003
    Posts: 9
    Originally posted by Ilja Preuss:
    What do you need this for? I do ask because this is a quite general (and possibly hard to answer) question, so knowing more about your needs might help us helping you...

    Thanks for your reply. Here are my questions about the optimization techniques:
    [list]First Problem:
    It seems to me that at least in the client version of the VM the following two source codes have a different performance (Source 2 seems to be better).
    Source 1:

    Source 2:

    Am I right or completely wrong? If I am right does this depend on the
    method inlining technique used in the VM?
    Anyway: Which methods are inlined and when are they inlined?
  • Second Problem:
    I have read that it is not advicable to use object pools with the

  • Java Hotspot VM. But I have used an iterator pool in my application
    and the performance has increased by 10 percent. To be more precise the
    code looks like this:

    and the classes which uses this iterator looks like this:

    Question: Is the increased performance dued to the not local life-time of the iterator objects or is this iterator pool also applicable to normal
    for-loops?
  • Third problem:

  • Because the cast-operators and the instanceof-operator may also
    decrease the performance I was wondering if there exists an optimization
    technique to optimistically eliminate these operators?

    Thanks Stephan
    [ October 27, 2003: Message edited by: stephan schweitzer ]
     
    I agree. Here's the link: http://aspose.com/file-tools
     
    subject: hot spot optimization techniques?