Hello, There is an opportunity to spill/load fewer registers in ZGC barriers. This is targetting JDK 16 jdk/jdk. JIRA: https://bugs.openjdk.java.net/browse/JDK-8246373 Webrev: http://cr.openjdk.java.net/~smonteith/8246373/webrev.0/ Tested with JTReg, SPECjbb2015, and other workloads. Thanks, Stuart