Re:Java BitSet performance-flicker mystery
by cospaia on Sunday February 06, 2022 @06:49PM
(#30238363)
I had this issue using JDK17 and 18 as well, so at least by default things are not better. =)
I wonder if there is a way that does not involve using `numactl`. It needs the container to run in privileged mode and that is not how the containers are run in the drag-racing benchmark...
Re:Java BitSet performance-flicker mystery
by CraigJPerry on Sunday February 06, 2022 @07:52PM
(#30238790)
Can you use the jvm’s -xx:+UseNUMA option instead?
Re:Java BitSet performance-flicker mystery
by cospaia on Tuesday February 08, 2022 @04:08PM
(#30264730)
Thanks! It does and it does not. Here's 100 rounds where it does: https://github.com/PEZ/ghost-chase-condition/tree/master/tes...
But in other cases I have it seems to not help that much. Not sure how to minimize those, but will try figure it out.
The thing that blew my mind when i ran into this was that the jvm had actually been NUMA aware for many years at that point but it was all turned off by default. This was jdk8 days so things are probably better now.
After i figured the root cause, I spent about a day logging results in excel as i tested various GC options, the only saving grace was i recall the Oracle documentation for GC options and their NUMA effects was pretty good. That optimisation time was really well spent though, i got meaningful improvements in both service latency and throughput.