Give more CPU time to GC in java?

Question

I have an java application that uses as much CPU as it can and, with it, a lot of memory (up to 80Gb).

I am optimizing the GC for that app and I want to tell the JVM to use a given percentage of time (60%) to the GC, else the amount of time the machine is not in GC is processing and allocating more memory.

I wanted to confirm that the -XX:CMSIncrementalDutyCycle=60 parameter is the thing I'm looking for and if there is any other parameters to give more power to the GC (I've already seen the CMSIncrementalPacing and CMSIncrementalDutyCycleMin)

Thanks a bunch!

Answer 1

You cannot set a ceiling for the CPU usage during the GC collections.

The CMSIncrementalDutyCycle is used to set the time between minor collections (see [1]), so you can control how often the GC runs and thus indirectly the CPU usage. But, there is no parameter that would allow you to control the CPU usage directly.