JDK-8337657 : AArch64: No need for acquire fence in safepoint poll during JNI calls
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 21,23,24
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • CPU: aarch64
  • Submitted: 2024-08-01
  • Updated: 2024-08-19
  • Resolved: 2024-08-09
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JDK 24
24 b11Fixed
Related Reports
Relates :  
JDK-8292591 - Experimentally add back barrier-less Java thread transitions
Relates :  
JDK-8189596 - AArch64: implementation for Thread-local handshakes
Description
There is call overhead in which LDAR, issued by the original implementation of JDK-8189596, plays a significant role. (more details in https://mail.openjdk.org/pipermail/hotspot-compiler-dev/2024-July/078698.html ) According to the later discussion https://mail.openjdk.org/pipermail/hotspot-compiler-dev/2024-July/078715.html it is no longer needed.

There are 2 places to change: SharedRuntime::generate_native_wrapper() and TemplateInterpreterGenerator::generate_native_entry().

The same approach is used in RISC-V port but this RFE is for AArch64 only.
Comments
Changeset: 358d77da Branch: master Author: Dmitry Chuyko <dchuyko@openjdk.org> Date: 2024-08-09 17:56:37 +0000 URL: https://git.openjdk.org/jdk/commit/358d77dafbe0e35d5b20340fccddc0fb8f3db82a
09-08-2024
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/20420 Date: 2024-08-01 13:36:26 +0000
01-08-2024