Hi there,
I'm working with a big project that usually takes 45 min to compile which is a long time. I've noticed that the processor load most of the times is only at 50%. So it should be possible to speed this up, right? Does someone have some hints?
thanks in advance,
Jan
java 1.4.2
win xp
3ghz intel cpu with hyperthreading 1 gb ram
It's disk access.
Check your import statements. If there are unused ones, remove them. That should reduce disk access (as the compiler checks if the classes are there even if they're not used). Don't know if that will give a substantial performance improvement but it should do something if there's tons of them.
Apart from that, all I can suggest is you try to increase harddisk performance. Try defragmenting, if you're running a slow harddisk and/or controller upgrade those, etc..
There's little else you can do without rearchitecturing to reduce the number of dependencies.
Playing with the heap value didn't have an significant effect.
Unfortunately I cannot reengineer the whole project but I'll keep the import statements in mind when changing or creating classes. The number of classes exceeds 10k but still it seems kind of slow. I'll propose to split the project up and create jars for the stable parts.
I call an ant script that does all the work. I am a little busy right now but thats what I found out :
compiling the JDK didn't work 100% because of some errors I didn't have time to resolve, however it created some thousand class files pretty fast so I think it should finish in the region of 5 min +-.
Assuming there is nothing wrong with my PC I took a look into the ant file where it seemed that not the actual compiling takes so long but the parsing and compiling of some scripts. At least thats what I think, is there an ant profiling tool ? ;)
I thought there might be some compiler setting that improves the java compile speed, however hearing your compile times it indicates that the problem lies somewhere else.
thanks for your efforts
jan
> Ehemm (hesitating ..., but) you are not by any chance
> using a built system dating back to the good old
> C/C++ times where each source file is compiled by an
> individual invocation of the compiler (i.e. javac)?
>
With C/C++ you can very well invoke the compiler on several sources.
posman@proli:/tmp/efe> cat x.c
void foo() { }
posman@proli:/tmp/efe> cat y.c
int main () {
foo();
return 0;
}
posman@proli:/tmp/efe> gcc x.c y.c -o z
posman@proli:/tmp/efe> ./z
posman@proli:/tmp/efe> echo $?
0
