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Re: Gcj binaries performance (arm-linux)
Andrew John Hughes wrote:
> 2008/5/9 Andrew Haley <aph@redhat.com>:
>> Andrew John Hughes wrote:
>> > 2008/4/29 ffileppo <ffileppo@libero.it>:
>> >> >
>> >> > aph@debian:~$ /home/aph/gcc-4.3.0-RC-20080301-install/bin/gcj MyPanel.class -O --main=MyPanel
>> >> > aph@debian:~$ ./a.out
>> >> > Test "Bubble Sort" (Num loop: 100)
>> >> > First loop time: 22
>> >> > Total time elapsed: 2197
>> >> >
>> >> > aph@debian:~$ /home/aph/gcc-4.3.0-RC-20080301-install/bin/gcj MyPanel.class -O2 --main=MyPanel
>> >> > aph@debian:~$ ./a.out
>> >> > Test "Bubble Sort" (Num loop: 100)
>> >> > First loop time: 20
>> >> > Total time elapsed: 1943
>>
>> >>
>>
>>>> Thanks for your help Andrew,
>> >> I'm getting good performance on target using -O / -O2
>>
>> >
>>
>>> So does gcj default to no optimisation? This is what these results
>> > suggest, as the -O version is about 18 times quicker.
>>
>> Yes, of course. That's standard for UNIX, as far as I'm aware: I don't
>> think I've ever come across a compiler that optimized unless it was
>> asked to.
>>
>> Andrew.
>>
>
> That makes sense, especially as something like -O2 will make debugging harder
> and ** probably has effect on some of the reflection properties of Java. **
I should bloody well hope not!
Andrew.