[GCJ] Performance of GUI applications on embedded systems

Fri Nov 7 18:56:00 GMT 2008

ffileppo wrote:
>>>> Here's one improvement. If you can get rid of the places in the GTK peers
>>>> where class and method lookups are performed at runtime you'll probably
>>>> have a fix. This shouldn't be a massive amount of work, just rather
>>>> boring.
>>>>>>>> In gcj,
>>>>>>>> * Compiled java code is quite fast.
>>>> * Class lookup by name is slow.
>>>> * Calling JNI code from compiled java code is quite fast.
>>>> * Calling compiled java code from JNI code is slow.
>>>> * Exceptions are slow.
>>> I'm testing your patch on my embedded system and now I can see that GUI performance are very much better (particularly during application startup).
>>>>>> Thank you so much!
>>>>>> However running my test case (please see my first post) I see that CPU usage is always at 100% (after the application is running),
>>> so the responsiveness is still not very good.
>> What do you expect? You're setting up a Timer with a delay of
>> 0 milliseconds between events, and it's running continuously.
>>>> Andrew.
>>>> You're right.
> However I'm experiencing slowness when testing some other GUI sample application (e.g. the test case attached at the end).
>> In this particular test case, the application takes a lot of time to startup (compared to the same device, running WinCE and CrEme JVM) and during start up the CPU usage is always at 100%.
>> After startup, I'v also noticed that highlighting and/or clicking a certain number of times on buttons cause the application to hang and after that the CPU usage is always 100%.

I've identified some serious GTK locking problems with this version of gcj.
I'm investigating.
Andrew.