first test

Wed Jul 14 21:51:00 GMT 2004

Am 14.07.2004 um 23:28 schrieb Bryce McKinlay:
> Alessandro Di Maria wrote:
>>> running it on Mac OS X 10.3.4 1.33 GHz G4:
>>>> java Loop
>> time: 2269
>>>> gcj --main=Loop -o Loop Loop.java
>> ./Loop
>> time: 4369
>>>> ??? the app compiled with gcj is twice as much slow as the one 
>> running through the VM ???
>> Redoing the test doesn't change much.
>>>> Have I done something wrong?
>>> You didn't say what version of gcj you are using, but until very 
> recently, gcj on Darwin (aka OS X) was very slow because it lacked 
> support for converting signals into NullPointerExceptions. This meant 
> that it had to insert an explicit check for null pointers every time 
> an object is accessed. You need to use the latest gcc from CVS to get 
> the new code, I don't think it has been added to the GCC 3.4 branch 
> (yet?).
>> Also, you should compile your code with -O2 to get the best 
> performance, however in this case it probably doesn't make much 
> difference because the vast majority of runtime is spent in the 
> various library calls.
>
Configured with: /Volumes/Work/gcc/src/gcc-3.4.1/configure 
--prefix=/usr/local/gcc-3.4.1 --enable-shared --disable-checking 
--enable-languages=c,c++,java --enable-debug
Thread model: posix
gcc version 3.4.1
I'm new to GCJ, normally I develop only on Java and wanted to test GCJ.
So just for curiosity, what does -O0 and -O2 mean?
I tried to compile and link in two seperate steps and get different 
times, but quite the same as with -O2:
time: 3410
Regards
Alessandro