Java G1 GC Processing Reference objects works slow

Question

I have hit counter running on Java. It works 24 hours and hits pass at about 100 times per second. During the day GC processing time slowly rises from 20-60 ms till 10000-60000

Answer 1

Its important that all my runs were with Yourkit profiler. I installed fastdebug build of OpenJDK7. At this version there is a parameter -XX:+TraceReferenceGC. After running with this parameter gc log shown about 5000 some finalizers. This problem was resolved by turning off socket probes of Yourkit.

Answer 2

As a first step you can use VisualVM or any tool to analyze your heap usage pattern. You might have a solution by optimising your code, by checking hotspots of object creation and that should be a permanant solution.

If that is not possible you have to find the optimal heap size and a GC algorithm suiting your applications behaviour. This is going to be a trial and error method. You will definitly have to go through tuning doc. The tuning you do now might again become inefficient later when your application behaviour changes or load pattern changes.

Try and find the suitable collector for you. You will be tweaking some parameters like

    -XX:+UseConcMarkSweepGC        
    -XX:SurvivorRatio=10 
    -XX:TargetSurvivorRatio=90 
    -XX:MaxTenuringThreshold=30

by trial and error.