java - NewRatio parameter not working with CMS garbage collector

Question

I switched to CMS collector for my application and throughput of application decreased by half. From GC logs, I see a high frequency of minor GCs happening (aroung 10 per second ). I have allocated a heap size of 4G. The JVM be default is using very small size for young gen (less than 40MB ). I want to try out CMS via increasing the size of young gen. Can you point me to right JVM parameter for this.

• I tried -XX:NewRatio but JVM ignored this parameter and there was no change in young gen sizes
• My java version is java version "1.6.0_14"

Answer 1

How did you set -XX:NewRatio, and on which JVM version?

Anyway. It could be ignored if you are also setting -XX:MaxNewSize=size, which is a feature, or if you are also setting -XX:+UseConcMarkSweepGC which is a known bug.