Provide documentation for setting up reasonable jvmopts settings

[ceedubs]

See gitter conversation.

[ceedubs]

@non would you be willing to paste any settings you would recommend? I can write up a little documentation that refers to them.

[non]

Sure, with the caveat that the release isn't done yet, here is what I'm currently using for Java 8:

-Dfile.encoding=UTF8
-Xms1G
-Xmx4G
-XX:+UseG1GC

(EDIT: oops, failed to include the G1GC option.)

[non]

I am also using GC debugging options just to get a sense of how memory usage is going (but I wouldn't recommend this for most folks since it ruins output):

-verbose:gc
-XX:+PrintGCTimeStamps
-XX:+PrintGCDetails

[dchenbecker]

You could always log the GC output to a file if you don't want it in your console. Personally I like having the logs there to look back to if I notice strange behavior that I think might be GC-related.

[ghost]

There is the .jvmopts file in the root dir, and in the README.md "We suggest you use Paul Philips's sbt script that will use the settings from Cats."

Is that enough?

[ghost]

Forgot to add that I have tried running with GC1 and saw a negative improvement. I think one issue could be that the provided .jvmopts will not be picked up sbt. So if you start playing with the settings, you will no doubt see an improvement, but only because they will improve the default sbt settings.

To use .jvmopts, you have to use PP's sbt script or similar