Is there any advantage in setting Xms and Xmx to the same value?

Question

Usually I set -Xms512m and -Xmx1g so that when JVM starts it allocates 512MB and gradually increases heap to 1GB as necessary. But I see these values s

Answer 1

There are some advantages.

• if you know the size is going to grow to the maximum, e.g. in a benchmark, you may as well start with the size you know you need.
• you can get better performance giving the program more memory that it might naturally give itself. YMWV

In general, I would make the Xms a value I am confident it will use, and the double this for head room for future use cases or situations we haven't tested for. i.e. a size we don't expect but it might use.

In short, the maximum is the point you would rather the program fail than use any more.