Re: Gcj binaries performance (arm-linux)
"Andrew John Hughes" <[email protected]>
| Newsgroups | gmane.comp.gcc.java.devel |
|---|---|
| Message-ID | <[email protected]> |
2008/5/9 Andrew Haley <[email protected]>: > Andrew John Hughes wrote: > > 2008/4/29 ffileppo <[email protected]>: > >> > > >> > 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 guess this is what you get from Java people who tend to expect everything to work best with no options... ;) I always pass plenty when hacking C or C++ code. -- Andrew :-) Support Free Java! Contribute to GNU Classpath and the OpenJDK http://www.gnu.org/software/classpath http://openjdk.java.net PGP Key: 94EFD9D8 (http://subkeys.pgp.net) Fingerprint: F8EF F1EA 401E 2E60 15FA 7927 142C 2591 94EF D9D8