Does tuning the GC help? [duplicate]

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Has anyone found Garbage Collection tuning to be useful?

Does it really help? Isn't the jvm written by much smarter people? What will be case to tune it manually?

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The JVM is well written, but no universal GC policy exists for every situation. Check this:

http://www.oracle.com/technetwork/java/gc-tuning-5-138395.html

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Tuning garbage collection will help your application performance when garbage collection is the bottle neck for your application. You can use the JVM command line argument -verbose:gc to help diagnose the issue.

For most applications, I would say that out of the box garbage collection should be sufficient. If you are having performance problems I would reevaluate your code.

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Until dynamically ergonomic systems and instrumentation APIs exist (hello IBM & Oracle? you know my email, let's talk), the JVM is still limited as a machine to a set amount of size at startup. A 64 mebibyte heap won't work for a large JBoss application, and there's no reason to have an 8 gibibyte heap for a calculation.

Additionally, JVMs offer a few different GC schemes as to not have one-size-fits-all.

I tune all of my operational JVMs by analyzing the GC logs. You tune your Linux kernels yes?