Speed Impact experiment on GCJ

Andrew Haley aph@redhat.com
Wed Feb 15 16:23:00 GMT 2006


Thomas Hallgren writes:
 > Andrew Haley wrote:
 > 
 > [thhal@localhost gcjtest]$ time java -server Client task.test servers.d result.d
 > 
 > real    0m0.510s
 > user    0m0.073s
 > sys     0m0.393s
 > 
 > 200.0   39
 > 300.0   1
 > 400.0   0
 > 500.0   1
 > 
 > REMARK: Obviously, the JIT discovers that the loop is not really a loop sometime
 > during the first iterations and decides to optimize pretty hard...

Indeed.  :-)

One thing we've all laearned about benchmarks: for a test to be in any
way meaningful it has to actually *do* something.

For what it's worth, I was quite suprised that gcj didn't spot the
same opportunity.  Maybe this is part of the value range propagation
optimizations that aren't yet in core gcc.

Andrew.



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