JDK-8357245 : [lworld] Potential performance regression of Unsafe::getAndSet after JDK-8351569
  • Type: Enhancement
  • Component: core-libs
  • Sub-Component: java.lang.invoke
  • Affected Version: repo-valhalla
  • Priority: P4
  • Status: New
  • Resolution: Unresolved
  • Submitted: 2025-05-19
  • Updated: 2025-05-19
Related Reports
Relates :  
JDK-8351569 - [lworld] Revisit atomic access modes in flat var handles
Relates :  
JDK-8343420 - [lworld] compiler/gcbarriers/TestG1BarrierGeneration.java after merging JDK-8334060 in jdk-24+18
Description
This issue's purpose is to keep track of a potential performance regression introduced with JDK-8351569 (and discovered while investigating JDK-8343420). JDK-8351569 introduced a new overloaded version of Unsafe::getAndSet that is not intrinsified (which is used by e.g. VarHandle::getAndSet). We should evaluate how much of a performance impact this can have and potentially intrinsify it or make it call the intrinsified version.
Comments
I think this is more of a compiler-side responsibility to add intrinsics for new unsafe operations, isn't it?
19-05-2025