Shawn Curry

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since Dec 18, 2003
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Recent posts by Shawn Curry

Guess I'm a johnny come lately to this discussion, but I have some interesting retorts to some of the performace topics that were discussed on this thread.
Basically, I have an XML parser I've been trying to squeeze a couple milliseconds out of; so I've rolled my own stack and hashmap data structures. Both grow by powers of 2.
The results I obtained were using a P4 @ 1.8GHz, J2SE 1.4.1, and J2EE 1.4.2.
As suggested by Josh Bloch here I built my testing framework to run n timed runs, and take an average of all the runs. Also, I'm running the JVM with the -Xnoclassgc option. Also, I wrote 2 init functions, one to build a sequential list, and one to build a random list.
  • Accessing with a single thread, the synchronized keyword did not affect my performace.
  • Sequentially numbered keys are faster in all cases.
  • HashMap suffers a penalty of approximately 5% on random lists.
  • Hashtable suffers nearly a 40% penatly.
  • HashMap is approximately 5% faster than Hashtable on random lists.
  • Hashtable is about 35% faster than HashMap on sequential lists.
  • In all cases MY implemention was faster


  • 32768 items, 30 runs, put(), remove():

    If anyone's still interested, I could post the testing framework.

    [ December 19, 2003: Message edited by: Shawn Curry ]
    17 years ago