New Write Barriers for G1

Posted on April 2, 2025

The Garbage First (G1) collector’s throughput sometimes trails that of other HotSpot VM collectors. The difference is caused by G1’s principle to be a garbage collector that balances latency and throughput and tries to meet a pause time goal. A large part of that can be attributed to the synchronization of the garbage collector with the application necessary for correct operation. With JDK-8340827 we substantially redesign how this synchronization works for much less impact on throughput. This post explains these fairly fundamental changes.

More at http://tschatzl.github.io/2025/02/21/new-write-barriers.html