Strange Performance Tests

Lars Andersen lars@rimfaxe.com
Wed Jul 10 11:57:00 GMT 2002



I have been running extensive tests comparing gcj vs Sun jdk1.4

The results are truly strange (to me) :

These measurements originates from benchmarking a real life java
program.

The first few runs on the Sun jdk is really slow, as would be expected
from the hotspot jit.

As you can see, GCJ starts out terrific, better than the Sun jdk ever
gets. But then it degenerates to about half the performance of the Sun
jdk. Clearly something is terribly wrong here?

Btw, i have had these tests running for hours the trend stays the same.
But it doesn't get worse either.


=============================================

GCJ - cvs snapshot

Total time -> 10ms     
Total time -> 4ms      
Total time -> 3ms     
Total time -> 3ms     
Total time -> 12ms     
Total time -> 2ms      
Total time -> 2ms    
Total time -> 2ms      
Total time -> 3ms      
Total time -> 3ms     
Total time -> 2ms      
Total time -> 2ms     
Total time -> 2ms     
Total time -> 3ms      
Total time -> 7ms      
Total time -> 9ms      
Total time -> 10ms     
Total time -> 7ms      
Total time -> 9ms      
Total time -> 10ms      
Total time -> 7ms      
Total time -> 8ms     
Total time -> 8ms     
Total time -> 23ms     
Total time -> 8ms      
Total time -> 8ms     
Total time -> 8ms      
Total time -> 8ms      
Total time -> 8ms      
Total time -> 10ms     
Total time -> 16ms      
Total time -> 10ms     
Total time -> 10ms     

==============================================
==============================================

SUN JDK 1.4

Total time -> 58ms     
Total time -> 84ms    
Total time -> 145ms    
Total time -> 8ms    
Total time -> 4ms     
Total time -> 8ms     
Total time -> 7ms     
Total time -> 3ms    
Total time -> 2ms     
Total time -> 5ms     
Total time -> 4ms    
Total time -> 2ms     
Total time -> 4ms    
Total time -> 20ms     
Total time -> 3ms     
Total time -> 4ms     
Total time -> 3ms     
Total time -> 2ms      
Total time -> 4ms      
Total time -> 2ms     
Total time -> 3ms    
Total time -> 3ms     
Total time -> 3ms    
Total time -> 14ms    
Total time -> 3ms    
Total time -> 4ms      
Total time -> 8ms     
Total time -> 4ms     
Total time -> 8ms     
Total time -> 4ms    

==============================================


/Lars Andersen



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