FtB Alpha 3 002: Tinkering with Java memory settings (TECHNICAL) (KmOCD)
Today on Feed the Beast testing, I am looking at the effect of Java memory settings on Minecraft performance. There is very little game play -- primarily a tour of our testing base -- the focus is on the memory consumption of Minecraft, and getting a baseline value for memory usage.
(Responses to your comments at the end; I cannot even comment on my own videos right now)
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Minecraft played in an overkill style by OCD players
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Memory and garbage collection flag information:
First, there are two different goals that need to be addressed.
Very often, FtB recommends 2 GB for it's packs. That's a lot of memory, and frankly, I don't think that you need that much. Certainly not for a client. So part of my goal is to reduce memory usage. On my personal machine, I run client, server, voice chat, and recorder program -- so I need to keep memory down.
And, one of my players has a system with plenty of memory, but an older CPU -- so for them, using less CPU and more memory is an acceptable tradeoff.
That's two different sets of goals, two different target sets of flags.
Step one is to get baseline information; step two is to improve that.
Now, for specifics:
Could you post the settings in the comments or description please?
I realize it might not be the final settings but from what i gather they seem good enough to use?
I thought I had that in the video?
Yes, right around 6:00 minutes.
-XX:SurvivorRatio=4 -XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses -XX:MaxHeapFreeRatio=25 -XX:MinHeapFreeRatio=20 -XX:CMSInitiatingOccupancyFraction=75
-XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintCommandLineFlags -XX:+PrintGCDetails -Xloggc:GC.log
There is a lot more detail available than that.
An older set of flags, stressing memory, targeted at java 6 on macs:
www.minecraftforum.net/topic/1541173-java-memory-and-minecraft/
Eyamaz's current recommendations for Java 7, focusing on run-time compiler settings :
forum.feed-the-beast.com/threads/jvm-arguments-for-modded-minecraft-updated-11-11-13.28994/