GC Bomb - CMS GC starves high priority system threads

Performance Tuning
#41

It is fixed in 1.5.0_06 :slight_smile:

#42

I reckon that counts as a ā€œreliable rumourā€ :wink:

Cas :slight_smile:

#43

Necro!

This bug has returned with a vengeance in JRE6ā€¦ and needs to be un-regressed! There are TIME_CRITICAL threads all over the place once more.

Cas :slight_smile:

#44

No wait! I tell a lie. Itā€™s different this timeā€¦ hereā€™s the symptoms:

Run Ultratron in Eclipse (java6ea) - game runs smoothly.
Run Ultratron as standalone executable, no Eclipse running in background - game runs smoothly.
Run Ultratron as standalone executable, Eclipse minimised in background - occasional, regular, 1 second pauses. Grr.

Any ideas on this particularly odd interaction? I feel that itā€™s something similar to what it was before.

Cas :slight_smile:

#45

Iā€™m not sure if itā€™s related, but Iā€™m noticing some strange behaviour of java6 at work:
Sometimes the whole OS (still running Win2000 here) almost freezes completely! When that happens (sometimes 5 times a day, sometimes 2 times a week), trying to kill all java processes solves the problem (that is, if the OS isnā€™t frozen too much).
The problem seems to be triggered by running java6 and a java 1.4.2 version at the same time, as axing Lotus Notesā€™ JRE (1.4.2) and replacing it with a java6 JRE seems to make the problem almost go away (making all applications use the same java6). Weird but true :-. Thereā€™s still the occasional short, system-wide pauses thoughā€¦

Cas, does Ultratron still have the same problem if you run Eclipse with the same JRE version as Ultratron?

#46

Yes.

The plot thickensā€¦ turns out all games are afflicted with 1-second pauses when Eclipse is running. It might just be a daft Eclipse thread doing it.

Cas :slight_smile:

#47

But then, are things any different between 1.4 and 1.6?

#48

This is probably due to the idle GC feature in Eclipse. When the IDE detects itself as ā€œidleā€, it periodically runs System.GC() to reduce perceived memory footprint. This however causes its CPU usage to spike and pauses games and other CPU intensive apps.

Itā€™s discussed in this bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=118335

You can run eclipse with: eclipse -vmargs -Dide.gc=false, as described in the post #8. This disables the idle GC and fixes the pauses, at least for me.

And oh, hi. First post, long time lurker. :slight_smile:

#49

And what an excellent first post :slight_smile: Most welcome.

Cas :slight_smile: