Comment by esaym

Comment by esaym 10 months ago

These modern garbage collectors are not simply free though. I got bored last year and went on a deep dive with GC params for Minecraft. For my needs I ended up with: -XX:+UseParallelGC -XX:MaxGCPauseMillis=300 -Xmx2G -Xms768M

When flying around in spectator mode, you'd see 3 to 4 processes using 100%. Changing to more modern collectors just added more load to the system. ZGC was the worst, with 16+ processes all using 100% cpu. With the ParallelGC, yes you'll get the occasional pause but at least my laptop is not burning hot fire.

plandis 10 months ago

Yes no GC is free (well perhaps Epsilon comes close :)

It’s a low pause GC so latencies, particularly tail latencies, can be more predictable and bounded. The tradeoff you make is that it uses more CPU time and memory in order to operate.

Reply View 0 replies

mike_hearn 10 months ago

Minecraft really needs generational ZGC (totally brand new) because Minecraft generates garbage at prodigious rates and non-generational GC collects less garbage per unit time.

Reply View 0 replies

namibj 10 months ago

You'll need more spare heap for ZGC.

Reply View 1 reply

ackfoobar 10 months ago

And using generational ZGC will probably lower CPU usage a lot.

Reply View | 0 replies

tuna74 10 months ago

Yes, this is why GCs work so bad for 3D games since you are usually limited by memory bandwidth and latency, especially on systems with unified RAM (no seperate GPU RAM).

Reply View 0 replies