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From Anthony Green <gr...@redhat.com>
Subject Re: I hope the JVM implements most using Java itself
Date Wed, 11 May 2005 18:34:21 GMT
On Wed, 2005-05-11 at 13:10 -0500, Archie Cobbs wrote:
> Those are good points.. I'm not saying JIT is bad, I'm just saying
> WAT has a place and can sometimes do things that JITs cannot because
> of time constraints.

Yes - in the real world, JITs don't always necessarily win.

Here's an example.  Wikipedia is currently using a gcj-built version of
Lucene to power their search feature.  Here's some text describing a
benchmark that help them make this decision:

----- cut here ------------------------------------------------
Crude, simple benchmark; does single-word fulltext search for “pope” 100
times sequentially. This is a fairly popular word, and returns 6890
results from the test database used (English Wikipedia, 2005-03-09
dump). Time returned is the average time spent for a request on the
client, over the second set of 100 runs.
                 GCJ 4.0 -O2: 588.3437 ms (fastest)
        Sun Java 1.5 -server: 636.9209 ms
                Sun Java 1.5: 695.5374 ms
                     GCJ 4.0: 707.2302 ms
                  Mono 1.1.6: 894.4488 ms (slowest)
Each version of the daemon read from the same index set, which I had
generated with the Mono-based version. (dotlucene 1.4 is index-
compatible with the Java Lucene 1.4.)
----- cut here ------------------------------------------------

I'm fairly certain we can do much better with additional compiler
options (-march=pentium4 and the like).

In any case, this is a showcase app for Apache + FSF technology working
together in an important real-world application.


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