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From "Joshua O'Madadhain" <>
Subject Re: Lucene Speed under diff JVMs
Date Thu, 05 Dec 2002 23:49:32 GMT
On Thu, 5 Dec 2002, Armbrust, Daniel C. wrote:

> I'm using the class that Otis wrote (see message from about 3 weeks ago)
> for testing the scalability of lucene (more results on that later) and I
> first tried running it under different versions of Java, to see where it
> runs the fastest.  The class simply creates an index out of randomly
> generated documents.
> All of the following were running on a dual CPU 1 GHz PIII Windows 2000
> machine that wasn't doing much else during the benchmark.  The indexing
> program was single threaded, so it only used one of the processors of
> the machine.

[snip specific measurements]

> As you can see, the IBM jvm pretty much smoked Suns.  And beat out
> JRockit as well.  Just a hunch, but it wouldn't surprise me if search
> times were also faster under the IBM jdk.  Has anyone else come to this
> conclusion?

Just a brief note on performance measurements and statistical sampling: no
offense, but if these are measurements of a single trial of 1000 documents
for each JVM, they're not so different that I'd be willing to conclude
that one JVM is notably faster for this task than another.  The problem is
compounded by the fact that it can be hard to tell just how much CPU is
being taken up by OS tasks (and this can fluctuate quite a lot).  If you
really want to quote statistics like this, using 5 or 10 trials would give
a more accurate notion of the real performance differences (if any).

Casuistically :),

Joshua O'Madadhain Per
   Joshua O'Madadhain: Information Scientist, Musician, Philosopher-At-Tall
It's that moment of dawning comprehension that I live for.  -- Bill Watterson
 My opinions are too rational and insightful to be those of any organization.

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