If, then, it turned out that changing the gc algorithm alone really solved a problem, that would indeed be very interesting to hear. That could help one know if they have any gc problem to begin with (in terms of unexpected pauses), and if addressing the real root cause of any gc problem helped or not. So I was very glad to see you mention doing logging and analysis. Rather, high heap use is usually solved by addressing whatever is using it unexpectedly (or raising the max, but not too high to cause long pauses).Īnd on a related but separate matter, high metaspace/permgen use is most often solved by proper sizing of the CF admin template cache size (or, again, simply raising that memory space’s max–or outright removing maxmetaspacesize in Java 8 and up, as then it is unrestricted in size). In my experience, gc choices and even gc “tuning” (other than heap or metaspace/permgen max sizes) are not the cause or even the best solution for most performance problems. I will be very interested to hear if it truly makes an observable difference for most over how g1 worked before, or even indeed over the parallel gc. Thanks for pointing out for folks the change in java 10’s g1gc, Carl. The memory foot print was smaller with G1.įor those that have applied G1 before it has a new parallel phase released in Java 10 speeding up performance (over that what you would notice for CF11 or CF2016 with Java 8) doing GC’s on multiple threads refer:Īs always do your own debugging and logging to know what outcomes are being achieved. Part of young collection is a pause however it is 100’s of milliseconds so other than being in the log is not felt by application load.Ĭoncurrently happening with the load is marking of dead objects taking place helping to limit the time of clearing up non referenced objects from memory. Perform same load and logging as before then again take notice of time spent in garbage collection. Perform one change to CF Java by either removing UseParallelGC (G1 is default so it will apply) or replace UseParallelGC with UseG1GC (sometimes it is better to read JVM arguments and know what values you are using). XX:+PrintGCDetails -verbose:gc -Xloggc:cfjvmGC.log #Garbage day game demo download free full#Suggest folks could do well to enable some Java logging and examine log file for performance related information like how long and when memory is in full garbage collection (java reminder full GC is a stop the world interval). When CF2018 installs it sets Parallel garbage collector. Of interest Java 11 is due for release in September (in a few days as I write). Java 9 and 10 offer G1 as default collector. Garbage first UseG1GC (G1) has been present for a while as an experimental option in Java 7 and released in Java 8.
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